MFRC53101T/0FE,112_技术文档

MFRC531

Standard ISO/IEC 14443 A/B reader solution

Rev. 3.6 — 27 February 2014

056636

Product data sheet

COMPANY PUBLIC

1. Introduction

This data sheet describes the functionality of the MFRC531 Integrated Circuit (IC). It

includes the functional and electrical specifications and from a system and hardware

viewpoint gives detailed information on how to design-in the device.

Remark: The MFRC531 supports all variants of the MIFARE Mini, MIFARE 1K,

MIFARE 4K, MIFARE Ultralight, MIFARE DESFire EV1 and MIFARE Plus RF

identification protocols. To aid readability throughout this data sheet, the MIFARE Mini,

MIFARE 1K, MIFARE 4K, MIFARE Ultralight, MIFARE DESFire EV1 and MIFARE Plus

products and protocols have the generic name MIFARE.

2. General description

The MFRC531 is a highly integrated reader IC for contactless communication at

13.56 MHz. The MFRC531 reader IC provides:

• outstanding modulation and demodulation for passive contactless communication

• a wide range of methods and protocols

• a small, fully integrated package

• pin compatibility with the MFRC500, MFRC530 and SLRC400

All protocol layers of the ISO/IEC 14443 A and ISO/IEC 14443 B communication

standards are supported provided:

• additional components, such as the oscillator, power supply, coil etc. are correctly

applied.

• standardized protocols, such as ISO/IEC 14443-4 and/or ISO/IEC 14443 B

anticollision are correctly implemented

The MFRC531 supports contactless communication using MIFARE higher baud rates

(see Section 9.12 on page 38). The receiver module provides a robust and efficient

demodulation/decoding circuitry implementation for compatible transponder signals (see

Section 9.10 on page 32).

The digital module, manages the complete ISO/IEC 14443 standard framing and error

detection (parity and CRC). In addition, it supports the fast MIFARE security algorithm for

authenticating the MIFARE products (see Section 9.14 on page 40).

The internal transmitter module (Section 9.9 on page 29) can directly drive an antenna

designed for a proximity operating distance up to 100 mm without any additional active

circuitry.

MFRC531

NXP Semiconductors

Standard ISO/IEC 14443 A/B reader solution

A parallel interface can be directly connected to any 8-bit microprocessor to ensure

reader/terminal design flexibility. In addition, Serial Peripheral Interface (SPI) compatibility

is supported (see Section 9.1.4 on page 9).

3. Features and benefits

3.1 General

 Highly integrated analog circuitry for demodulating and decoding card/label response

 Buffered output drivers enable antenna connection using the minimum of external

components

 Proximity operating distance up to 100 mm

 Supports both ISO/IEC 14443 A and ISO/IEC 14443 B standards

 Supports the MIFARE Mini, MIFARE 1K, MIFARE 4K protocols

 Contactless communication at MIFARE higher baud rates (up to 424 kBd)

 Crypto1 and secure non-volatile internal key memory

 Pin-compatible with the MFRC500, MFRC530 and the SLRC400

 Parallel microprocessor interface with internal address latch and IRQ line

 SPI compatibility

 Flexible interrupt handling

 Automatic detection of parallel microprocessor interface type

 64-byte send and receive FIFO buffer

 Hard reset with low power function

 Software controlled Power-down mode

 Programmable timer

 Unique serial number

 User programmable start-up configuration

 Bit-oriented and byte oriented framing

 Independent power supply pins for analog, digital and transmitter modules

 Internal oscillator buffer optimized for low phase jitter enables 13.56 MHz quartz

connection

 Clock frequency filtering

 3.3 V to 5 V operation for transmitter in short range and proximity applications

 3.3 V or 5 V operation for the digital module

MFRC531

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4. Applications

 Electronic payment systems

 Identification systems

 Access control systems

 Subscriber services

 Banking systems

 Digital content systems

5. Quick reference data

Table 1.

Symbol

T_amb

Quick reference data

Parameter

Conditions

Min

40

0.5

1.0

-

Typ

Max

Unit

C

V

ambient temperature

storage temperature

digital supply voltage

analog supply voltage

TVDD supply voltage

-

+150

T_stg

-

+150

V_DDD

5

-

6

V_DDA

6

V

V_DD(TVDD)

V_i

6

V

input voltage (absolute

value)

on any digital pin to DVSS

on pin RX to AVSS

V_DDD+ 0.5

V_DDA+ 0.5

1.0

V

-

V

I_LI

input leakage current

TVDD supply current

-

mA

I_DD(TVDD)

continuous wave

-

150

6. Ordering information

Table 2.

Ordering information

Type number

Package

Name

Description

Version

SOT287-1

MFRC53101T/0FE SO32

plastic small outline package; 32 leads; body width 7.5 mm

MFRC531

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7. Block diagram

NWR NRD NCS

ALE

21

A0 A1 A2

22 23 24

AD0 to AD7/D0 to D7

13 14 15 16 17 18 19 20

10

11

9

VOLTAGE

MONITOR

AND

POWER ON

DETECT

25

12

PARALLEL INTERFACE CONTROL

(INCLUDING AUTOMATIC INTERFACE DETECTION AND SYNCHRONISATION)

DVDD

DVSS

STATE MACHINE

FIFO CONTROL

64-BYTE FIFO

COMMAND REGISTER

RESET

CONTROL

PROGRAMMABLE TIMER

INTERRUPT CONTROL

POWER DOWN 31

CONTROL

CONTROL REGISTER

BANK

RSTPD

IRQ

2

CRC16/CRC8

GENERATION AND CHECK

EEPROM

ACCESS

32 × 16-BYTE

EEPROM

CONTROL

PARALLEL/SERIAL CONVERTER

BIT COUNTER

MASTER KEY BUFFER

CYRPTO1 UNIT

PARITY GENERATION AND CHECK

FRAME GENERATION AND CHECK

BIT DECODING

BIT ENCODING

32-BIT PSEUDO

RANDOM GENERATOR

3

4

MFIN

SERIAL DATA SWITCH

MFOUT

LEVEL SHIFTERS

1

CLOCK

AMPLITUDE

RATING

OSCIN

CORRELATION

AND

BIT DECODING

GENERATION,

FILTERING AND

DISTRIBUTION

OSCILLATOR

32

REFERENCE

VOLTAGE

OSCOUT

26

AVDD

AVSS

Q-CLOCK

GENERATION

POWER ON

DETECT

28

I-CHANNEL

Q-CHANNEL

ANALOG

TEST

MULTIPLEXER

AMPLIFIER

I-CHANNEL

Q-CHANNEL

TRANSMITTER CONTROL

DEMODULATOR

GND

V

MFRC531

GND

8

V

30

27

29

RX

5

7

6

VMID

AUX

TVSS

TX1

TX2

TVDD

001aal218

Fig 1. MFRC531 block diagram

MFRC531

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8. Pinning information

1

2

32

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

OSCIN

IRQ

OSCOUT

RSTPD

VMID

3

MFIN

4

MFOUT

TX1

RX

5

AVSS

6

TVDD

AUX

7

TX2

AVDD

8

TVSS

DVDD

MFRC531

9

NCS

A2/SCK

A1

10

11

12

13

14

15

16

NWR/R/NW/nWrite

NRD/NDS/nDStrb

DVSS

A0/nWait/MOSI

ALE/AS/nAStrb/NSS

D7/AD7

D6/AD6

D5/AD5

D4/AD4

AD0/D0

AD1/D1

AD2/D2

AD3/D3

001aal219

Fig 2. MFRC531 pin configuration

8.1 Pin description

Table 3.

Pin description

Symbol

Type^[1]

Description

1

OSCIN

I

oscillator/clock inputs:

crystal oscillator input to the oscillator’s inverting amplifier

externally generated clock input; f_osc= 13.56 MHz

2

IRQ

O

I

interrupt request generates an output signaling an interrupt event

ISO/IEC 14443 A MIFARE serial data interface input

ISO/IEC 14443 A MIFARE serial data interface output

transmitter 1 modulated carrier output; 13.56 MHz

3

4^[2]

MFIN

MFOUT

TX1

O

P

O

G

I

5

6

TVDD

TX2

transmitter power supply for the TX1 and TX2 output stages

transmitter 2 modulated carrier output; 13.56 MHz

7

8

TVSS

NCS

transmitter ground for the TX1 and TX2 output stages

not chip select input: selects and activates the microprocessor interface

9

10^[3]

NWR

I

not write input: generates the strobe signal for writing data to the registers when

applied to pins D0 to D7

R/NW

nWrite

NRD

I

read not write input: switches between read or write cycles

not write input: selects the read or write cycle to be performed

11^[3]

not read input: generates the strobe signal for reading data from the registers

when applied to pins D0 to D7

NDS

I

not data strobe input: generates the strobe signal for the read and write cycles

digital ground

nDStrb

DVSS

I

12

G

MFRC531

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Table 3.

Pin description …continued

Symbol

Type^[1]

Description

13

D0

O

SPI master in, slave out output

13 to 20^[3]D0 to D7

AD0 to AD7

ALE

I/O

8-bit bidirectional data bus input/output on pins D0 to D7

8-bit bidirectional address and data bus input/output on pins AD0 to AD7

address latch enable input for pins AD0 to AD5; HIGH latches the internal address

address strobe input for pins AD0 to AD5; HIGH latches the internal address

not address strobe input for pins AD0 to AD5; LOW latches the internal address

not slave select strobe input for SPI communication

address line 0 is the address register bit 0 input

not wait output:

I/O

21^[3]

I

AS

I

nAStrb

NSS

A0

I

22^[3]

I

nWait

O

LOW starts an access cycle

HIGH ends an access cycle

MOSI

A1

I

SPI master out, slave in

23

24^[3]

I

address line 1 is the address register bit 1 input

address line 2 is the address register bit 2 input

SPI serial clock input

A2

I

SCK

DVDD

AVDD

AUX

I

25

26

27

P

O

digital power supply

analog power supply for pins OSCIN, OSCOUT, RX, VMID and AUX

auxiliary output is used to generate analog test signals. The output signal is

selected using the TestAnaSelect register’s TestAnaOutSel[4:0] bits

28

29

AVSS

RX

G

I

analog ground

receiver input: used as the card response input. The carrier is load modulated at

13.56 MHz, drawn from the antenna circuit

30

31

VMID

P

I

internal reference voltage pin provides the internal reference voltage as a supply

Remark: It must be connected to a 100 nF block capacitor connected between pin

VMID and ground

RSTPD

reset and power-down input:

HIGH: the internal current sinks are switched off, the oscillator is inhibited and

the input pads are disconnected

LOW (negative edge): start internal reset phase

32

OSCOUT

O

crystal oscillator output for the oscillator’s inverting amplifier

[1] Pin types: I = Input, O = Output, I/O = Input/Output, P = Power and G = Ground.

[2] The SLRC400 uses pin name SIGOUT for pin MFOUT. The MFRC531 functionality includes test functions for the SLRC400 using pin

MFOUT.

[3] These pins provide different functionality depending on the selected microprocessor interface type (see Section 9.1 on page 7 for

detailed information).

MFRC531

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9. Functional description

9.1 Digital interface

9.1.1 Overview of supported microprocessor interfaces

The MFRC531 supports direct interfacing to various 8-bit microprocessors. Alternatively,

the MFRC531 can be connected to a PC’s Enhanced Parallel Port (EPP). Table 4 shows

the parallel interface signals supported by the MFRC531.

Table 4.

Supported microprocessor and EPP interface signals

Bus control signals

Bus

Separated address

and data bus

Multiplexed address and data bus

Separated read and

write strobes

control

NRD, NWR, NCS

NRD, NWR, NCS, ALE

AD0, AD1, AD2, AD3, AD4, AD5

AD0 to AD7

address A0, A1, A2

data

D0 to D7

Common read and write control

strobe

R/NW, NDS, NCS

R/NW, NDS, NCS, AS

AD0, AD1, AD2, AD3, AD4, AD5

AD0 to AD7

address A0, A1, A2

data

D0 to D7

Common read and write control

strobe with handshake

-

nWrite, nDStrb, nAStrb, nWait

AD0, AD1, AD2, AD3, AD4, AD5

AD0 to AD7

(EPP)

address

data

9.1.2 Automatic microprocessor interface detection

After a Power-On or Hard reset, the MFRC531 resets parallel microprocessor interface

mode and detects the microprocessor interface type.

The MFRC531 identifies the microprocessor interface using the logic levels on the control

pins. This is performed using a combination of fixed pin connections and the dedicated

Initialization routine (see Section 9.7.4 on page 28).

MFRC531

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9.1.3 Connection to different microprocessor types

The connection to various microprocessor types is shown in Table 5.

Table 5.

Connection scheme for detecting the parallel interface type

Parallel interface type and signals

MFRC531

pins

Separated read/write strobe Common read/write strobe

Dedicated

Multiplexed Dedicated

Multiplexed Multiplexed

address bus

address

bus

address bus address bus address bus with

handshake

ALE

A2

HIGH

A2

ALE

HIGH

A2

AS

nAStrb

HIGH

LOW

HIGH

NRD

NWR

NCS

LOW

A1

HIGH

LOW

HIGH

A0

nWait

NRD

NWR

NCS

D7 to D0

NRD

NWR

NCS

D7 to D0

NDS

R/NW

NCS

NDS

nDStrb

nWrite

LOW

R/NW

NCS

AD7 to AD0 D7 to D0

AD7 to AD0

9.1.3.1 Separate read and write strobe

MFRC531

NCS

MFRC531

NCS

address bus (A3 to An)

non-multiplexed address

ADDRESS

DECODER

ADDRESS

DECODER

LOW

HIGH

A2

A1

A0

address bus (A0 to A2)

data bus (D0 to D7)

A0 to A2

D0 to D7

multiplexed address/data (AD0 to AD7)

AD0 to AD7

HIGH

address latch enable (ALE)

Read strobe (NRD)

ALE

Read strobe (NRD)

Write strobe (NWR)

NRD

NWR

NRD

NWR

Write strobe (NWR)

001aal220

Fig 3. Connection to microprocessor: separate read and write strobes

Refer to Section 13.4.1 on page 93 for timing specification.

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9.1.3.2 Common read and write strobe

MFRC531

NCS

MFRC531

NCS

address bus (A3 to An)

non-multiplexed address

ADDRESS

DECODER

ADDRESS

DECODER

LOW

HIGH

LOW

A2

A1

A0

address bus (A0 to A2)

data bus (D0 to D7)

A0 to A2

D0 to D7

multiplexed address/data (AD0 to AD7)

AD0 to AD7

HIGH

Address strobe (AS)

Data strobe (NDS)

Read/Write (R/NW)

ALE

Data strobe (NDS)

Read/Write (R/NW)

NRD

NWR

NRD

NWR

001aal221

Fig 4. Connection to microprocessor: common read and write strobes

Refer to Section 13.4.2 on page 94 for timing specification.

9.1.3.3 Common read and write strobe: EPP with handshake

MFRC531

NCS

LOW

HIGH

A2

A1

A0

HIGH

nWait

multiplexed address/data (AD1 to AD8)

AD0 to AD7

Address strobe (nAStrb)

Data strobe (nDStrb)

Read/Write (nWrite)

ALE

NRD

NWR

001aal222

Fig 5. Connection to microprocessor: EPP common read/write strobes and handshake

Refer to Section 13.4.3 on page 95 for timing specification.

Remark: In the EPP standard, a chip select signal is not defined. To cover this situation,

the status of the NCS pin can be used to inhibit the nDStrb signal. If this inhibitor is not

used, it is mandatory that pin NCS is connected to pin DVSS.

Remark: After each Power-On or Hard reset, the nWait signal on pin A0 is

high-impedance. nWait is defined as the first negative edge applied to the nAStrb pin after

the reset phase. The MFRC531 does not support the Read Address Cycle.

9.1.4 Serial Peripheral Interface

The MFRC531 provides compatibility with the 5-wire Serial Peripheral Interface (SPI)

standard and acts as a slave during SPI communication. The SPI clock signal SCK must

be generated by the master. Data communication from the master to the slave uses the

MOSI line. The MISO line sends data from the MFRC531 to the master.

MFRC531

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Table 6.

SPI compatibility

MFRC531 pins

SPI pins

NSS

ALE

A2

SCK

A1

LOW

A0

MOSI

NRD

NWR

NCS

D7 to D1

D0

HIGH

LOW

do not connect

MISO

Figure 6 shows the microprocessor connection to the MFRC531 using SPI.

MFRC531

LOW

NCS

SCK

LOW

A2

A1

MOSI

A0

MISO

D0

NSS

ALE

001aal223

Fig 6. Connection to microprocessor: SPI

Remark: The SPI implementation for MFRC531 conforms to the SPI standard and

ensures that the MFRC531 can only be addressed as a slave.

9.1.4.1 SPI read data

The structure shown in Table 7 must be used to read data using SPI. It is possible to read

up to n-data bytes. The first byte sent defines both, the mode and the address.

Table 7.

SPI read data

Byte 0

Byte 1

address 1 address 2 ... address n

data 0 data 1 ... data n  1

Byte 2

... Byte n

Byte n + 1

00

MOSI

MISO

address 0

XX

data n

The address byte must meet the following criteria:

• the Most Significant Bit (MSB) of the first byte sets the mode. To read data from the

MFRC531 the MSB is set to logic 1

• bits [6:1] define the address

• the Least Significant Bit (LSB) should be set to logic 0.

As shown in Table 8, all the bits of the last byte sent are set to logic 0.

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Table 8.

SPI read address

Address

(MOSI)

Bit 7

(MSB)

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

(LSB)

byte 0

1

address address address address address address reserved

byte 1 to byte n reserved address address address address address address reserved

byte n + 1

0

[1] All reserved bits must be set to logic 0.

9.1.4.2 SPI write data

The structure shown in Table 9 must be used to write data using SPI. It is possible to write

up to n-data bytes. The first byte sent defines both the mode and the address.

Table 9.

SPI write data

Byte 0

Byte 1

data 0

XX

Byte 2

data 1

XX

...

Byte n

data n  1

XX

Byte n + 1

data n

XX

MOSI

MISO

address

XX

The address byte must meet the following criteria:

• the MSB of the first byte sets the mode. To write data to the MFRC531, the MSB is set

to logic 0

• bits [6:1] define the address

• the LSB should be set to logic 0.

SPI write mode writes all data to the address defined in byte 0 enabling effective write

cycles to the FIFO buffer.

Table 10. SPI write address

Address line

(MOSI)

Bit 7

(MSB)

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

(LSB)

byte 0

0

address address address address address address reserved

data data data data data data data

byte 1 to byte

n + 1

data

[1] All reserved bits must be set to logic 0.

Remark: The data bus pins D7 to D1 must be disconnected.

Refer to Section 13.4.4 on page 97 for the timing specification.

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9.2 Memory organization of the EEPROM

Table 11. EEPROM memory organization diagram

Block

Byte address Access Memory content Refer to

Position Address

0

00h to 0Fh

R

product

information field

Section 9.2.1 on page 13

Section 9.2.2.1 on page 14

1

10h to 1Fh

R/W

W

StartUp register

initialization file

2

20h to 2Fh

3

30h to 3Fh

register

initialization file

Section 9.2.2.3 “Register

initialization file

(read/write)” on page 16

4

40h to 4Fh

user data or

second

initialization

5

50h to 5Fh

6

60h to 6Fh

7

70h to 7Fh

8

80h to 8Fh

keys for Crypto1

Section 9.2.3 on page 16

9

90h to 9Fh

W

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

A

A0h to AFh

B0h to BFh

C0h to CFh

D0h to DFh

E0h to EFh

F0h to FFh

W

B

W

C

W

D

W

E

W

F

W

10

11

12

13

14

15

16

17

18

19

1A

1B

1C

1D

1E

1F

100h to 10Fh

110h to 11Fh

120h to 12Fh

130h to 13Fh

140h to 14Fh

150h to 15Fh

160h to 16Fh

170h to 17Fh

180h to 18Fh

190h to 19Fh

1A0h to 1AFh

1B0h to 1BFh

1C0h to 1CFh

1D0h to 1DFh

1E0h to 1EFh

1F0h to 1FFh

W

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9.2.1 Product information field (read only)

Table 12. Product information field

Byte

Symbol

Access Value Description

15

CRC

R

-

the content of the product information field

is secured using a CRC byte which is

checked during start-up

14

RsMaxP

R

-

maximum source resistance for the

p-channel driver transistor on pins TX1 and

TX2

The source resistance of the p-channel

driver transistors of pin TX1 and TX2 can be

adjusted using the value GsCfgCW[5:0] in

the CwConductance register (see

Section 9.9.3 on page 30). The mean value

of the maximum adjustable source

resistance for pins TX1 and TX2 is stored

as an integer value in  in this byte. Typical

values for RsMaxP are between 60  to

140 . This value is denoted as maximum

adjustable source resistance R_S(ref)maxPand

is measured by setting the CwConductance

register’s GsCfgCW[5:0] bits to 01h.

13 to 12 Internal

R

-

two bytes for internal trimming parameters

11 to 8 Product Serial Number

a unique four byte serial number for the

device

7 to 5

4 to 0

reserved

R

-

Product Type

Identification

the MFRC531 is a member of a new family

of highly integrated reader ICs. Each

member of the product family has a unique

product type identification. The value of the

product type identification is shown in

Table 13.

Table 13. Product type identification definition

Definition

Byte

Product type identification bytes

0

1

2

3

4^[1]

Value

30h

FFh

0Fh

XXh

[1] Byte 4 contains the current version number.

9.2.2 Register initialization files (read/write)

Register initialization from address 10h to address 2Fh is performed automatically during

the initializing phase (see Section 9.7.3 on page 28) using the StartUp register

initialization file.

In addition, the MFRC531 registers can be initialized using values from the register

initialization file when the LoadConfig command is executed (see Section 11.4.1 on

page 86).

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Remark: The following points apply to initialization:

• the Page register (addressed using 10h, 18h, 20h, 28h) is skipped and not initialized.

• make sure that all PreSetxx registers are not changed.

• make sure that all register bits that are reserved are set to logic 0.

9.2.2.1 StartUp register initialization file (read/write)

The EEPROM memory block address 1 and 2 contents are used to automatically set the

register subaddresses 10h to 2Fh during the initialization phase. The default values stored

in the EEPROM during production are shown in Section 9.2.2.2 “Factory default StartUp

register initialization file”.

The byte assignment is shown in Table 14.

Table 14. Byte assignment for register initialization at start-up

EEPROM byte address

Register address

Remark

skipped

copied

…

10h (block 1, byte 0)

10h

11h

…

11h

…

2Fh (block 2, byte 15)

2Fh

copied

9.2.2.2 Factory default StartUp register initialization file

During the production tests, the StartUp register initialization file is initialized using the

default values shown in Table 15. During each power-up and initialization phase, these

values are written to the MFRC531’s registers.

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Table 15. Shipment content of StartUp configuration file

EEPROM Register Value Symbol

Description

byte

address

10h

11h

10h

11h

00h

58h

Page

free for user

TxControl

transmitter pins TX1 and TX2 are switched off, bridge driver

configuration, modulator driven from internal digital circuitry

12h

13h

14h

15h

16h

17h

18h

19h

1Ah

1Bh

1Ch

1Dh

1Eh

12h

13h

14h

15h

16h

17h

18h

19h

1Ah

1Bh

1Ch

1Dh

1Eh

3Fh

19h

13h

3Fh

3Bh

00h

73h

08h

ADh

FFh

1Eh

41h

CwConductance

ModConductance

CoderControl

ModWidth

source resistance of TX1 and TX2 is set to minimum

defines the output conductance

ISO/IEC 14443 A coding is set

pulse width for Miller pulse coding is set to standard configuration

pulse width of Start Of Frame (SOF)

ModWidthSOF

TypeFraming

Page

ISO/IEC 14443 A framing is set

free for user

RxControl1

ISO/IEC 14443 A is set and internal amplifier gain is maximum

bit-collisions always evaluate to HIGH in the data bit stream

BitPhase[7:0] is set to standard configuration

MinLevel[3:0] and CollLevel[3:0] are set to maximum

ISO/IEC 14443 A is set

DecoderControl

BitPhase

RxThreshold

BPSKDemControl

RxControl2

use Q-clock for the receiver, automatic receiver off is switched on,

decoder is driven from internal analog circuitry

1Fh

20h

21h

22h

23h

24h

25h

26h

27h

28h

29h

1Fh

20h

21h

22h

23h

24h

25h

26h

27h

28h

29h

00h

06h

03h

63h

00h

08h

ClockQControl

Page

automatic Q-clock calibration is switched on

free for user

RxWait

frame guard time is set to six bit-clocks

ChannelRedundancy channel redundancy is set using ISO/IEC 14443 A

CRCPresetLSB

CRCPresetMSB

PreSet25

CRC preset value is set using ISO/IEC 14443 A

MFOUTSelect

PreSet27

pin MFOUT is set LOW

-

Page

free for user

FIFOLevel

WaterLevel[5:0] FIFO buffer warning level is set to standard

configuration

2Ah

2Bh

2Ch

2Ah

2Bh

2Ch

07h

06h

0Ah

TimerClock

TimerControl

TimerReload

TPreScaler[4:0] is set to standard configuration, timer unit restart

function is switched off

Timer is started at the end of transmission, stopped at the beginning

of reception

TReloadValue[7:0]: the timer unit preset value is set to standard

configuration

2Dh

2Eh

2Fh

2Dh

2Eh

2Fh

02h

00h

IRQPinConfig

PreSet2E

pin IRQ is set to high-impedance

-

PreSet2F

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9.2.2.3 Register initialization file (read/write)

The EEPROM memory content from block address 3 to 7 can initialize register sub

addresses 10h to 2Fh when the LoadConfig command is executed (see Section 11.4.1 on

page 86). This command requires the EEPROM starting byte address as a two byte

argument for the initialization procedure.

The byte assignment is shown in Table 16.

Table 16. Byte assignment for register initialization at startup

EEPROM byte address

EEPROM starting byte address

EEPROM + 1 starting byte address

...

Register address

Remark

skipped

copied

…

10h

11h

…

EEPROM + 31 starting byte address

2Fh

copied

The register initialization file is large enough to hold values for two initialization sets and

up to one block (16-byte) of user data.

Remark: The register initialization file can be read/written by users and these bytes can

be used to store other user data.

After each power-up, the default configuration enables the MIFARE and ISO/IEC 14443 A

protocol.

9.2.3 Crypto1 keys (write only)

MIFARE security requires specific cryptographic keys to encrypt data stream

communication on the contactless interface. These keys are called Crypto1 keys.

9.2.3.1 Key format

Keys stored in the EEPROM are written in a specific format. Each key byte must be split

into lower four bits k0 to k3 (lower nibble) and the higher four bits k4 to k7 (higher nibble).

Each nibble is stored twice in one byte and one of the two nibbles is bit-wise inverted. This

format is a precondition for successful execution of the LoadKeyE2 (see Section 11.6.1 on

page 88) and LoadKey commands (see Section 11.6.2 on page 88).

Using this format, 12 bytes of EEPROM memory are needed to store a 6-byte key. This is

shown in Figure 7.

Master key byte

0 (LSB)

1

5 (MSB)

Master key bits k7 k6 k5 k4 k7 k6 k5 k4 k3 k2 k1 k0 k3 k2 k1 k0 k7 k6 k5 k4 k7 k6 k5 k4 k3 k2 k1 k0 k3 k2 k1 k0

EEPROM byte

k7 k6 k5 k4 k7 k6 k5 k4 k3 k2 k1 k0 k3 k2 k1 k0

n

n + 1

n + 2

n + 3

n + 10

5Ah

n + 11

A5h

address

5Ah

F0h

5Ah

E1h

Example

001aak640

Fig 7. Key storage format

Example: The value for the key must be written to the EEPROM.

• If the key was: A0h A1h A2h A3h A4h A5h then:

• 5Ah F0h 5Ah E1h 5Ah D2h 5Ah C3h 5Ah B4h 5Ah A5h would be written.

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Remark: It is possible to load data for other key formats into the EEPROM key storage

location. However, it is not possible to validate card authentication with data which will

cause the LoadKeyE2 command (see Section 11.6.1 on page 88) to fail.

9.2.3.2 Storage of keys in the EEPROM

The MFRC531 reserves 384 bytes of memory in the EEPROM for the Crypto1 keys. No

memory segmentation is used to mirror the 12-byte structure of key storage. Thus, every

byte of the dedicated memory area can be the start of a key.

Example: If the key loading cycle starts at the last byte address of an EEPROM block, (for

example, key byte 0 is stored at 12Fh), the next bytes are stored in the next EEPROM

block, for example, key byte 1 is stored at 130h, byte 2 at 131h up to byte 11 at 13Ah.

Based on the 384 bytes of memory and a single key needing 12 bytes, then up to 32

different keys can be stored in the EEPROM.

Remark: It is not possible to load a key exceeding the EEPROM byte location 1FFh.

9.3 FIFO buffer

An 8  64 bit FIFO buffer is used in the MFRC531 to act as a parallel-to-parallel converter.

It buffers both the input and output data streams between the microprocessor and the

internal circuitry of the MFRC531. This makes it possible to manage data streams up to

64 bytes long without needing to take timing constraints into account.

9.3.1 Accessing the FIFO buffer

9.3.1.1 Access rules

The FIFO buffer input and output data bus is connected to the FIFOData register. Writing

to this register stores one byte in the FIFO buffer and increments the FIFO buffer write

pointer. Reading from this register shows the FIFO buffer contents stored at the FIFO

buffer read pointer and increments the FIFO buffer read pointer. The distance between the

write and read pointer can be obtained by reading the FIFOLength register.

When the microprocessor starts a command, the MFRC531 can still access the FIFO

buffer while the command is running. Only one FIFO buffer has been implemented which

is used for input and output. Therefore, the microprocessor must ensure that there are no

inadvertent FIFO buffer accesses. Table 17 gives an overview of FIFO buffer access

during command processing.

Table 17. FIFO buffer access

Active

FIFO buffer

Remark

command

p Write

p Read

StartUp

Idle

-

Transmit

Receive

Transceive

yes

-

yes

the microprocessor has to know the state of the

command (transmitting or receiving)

WriteE2

yes

-

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Table 17. FIFO buffer access …continued

Active

command

FIFO buffer

p Write

yes

Remark

p Read

ReadE2

yes

the microprocessor has to prepare the arguments,

afterwards only reading is allowed

LoadKeyE2

LoadKey

yes

-

Authent1

Authent2

LoadConfig

CalcCRC

yes

9.3.2 Controlling the FIFO buffer

In addition to writing to and reading from the FIFO buffer, the FIFO buffer pointers can be

reset using the FlushFIFO bit. This changes the FIFOLength[6:0] value to zero, bit

FIFOOvfl is cleared and the stored bytes are no longer accessible. This enables the FIFO

buffer to be written with another 64 bytes of data.

9.3.3 FIFO buffer status information

The microprocessor can get the following FIFO buffer status data:

• the number of bytes stored in the FIFO buffer: bits FIFOLength[6:0]

• the FIFO buffer full warning: bit HiAlert

• the FIFO buffer empty warning: bit LoAlert

• the FIFO buffer overflow warning: bit FIFOOvfl.

Remark: Setting the FlushFIFO bit clears the FIFOOvfl bit.

The MFRC531 can generate an interrupt signal when:

• bit LoAlertIRq is set to logic 1 and bit LoAlert = logic 1, pin IRQ is activated.

• bit HiAlertIRq is set to logic 1 and bit HiAlert = logic 1, pin IRQ activated.

The HiAlert flag bit is set to logic 1 only when the WaterLevel[5:0] bits or less can be

stored in the FIFO buffer. The trigger is generated by Equation 1:

HiAlert = 64 – FIFOLength  WaterLevel

(1)

The LoAlert flag bit is set to logic 1 when the FIFOLevel register’s WaterLevel[5:0] bits or

less are stored in the FIFO buffer. The trigger is generated by Equation 2:

LoAlert = FIFOLength  WaterLevel

(2)

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9.3.4 FIFO buffer registers and flags

Table 17 shows the related FIFO buffer flags in alphabetic order.

Table 18. Associated FIFO buffer registers and flags

Flags

Register name

FIFOLength

ErrorFlag

Bit

Register address

FIFOLength[6:0]

FIFOOvfl

6 to 0

04h

0Ah

09h

03h

06h

07h

03h

06h

07h

29h

4

FlushFIFO

HiAlert

Control

0

PrimaryStatus

InterruptEn

InterruptRq

PrimaryStatus

InterruptEn

InterruptRq

FIFOLevel

1

HiAlertIEn

HiAlertIRq

LoAlert

1

0

LoAlertIEn

LoAlertIRq

WaterLevel[5:0]

0

5 to 0

9.4 Interrupt request system

The MFRC531 indicates interrupt events by setting the PrimaryStatus register bit IRq (see

Section 10.5.1.4 “PrimaryStatus register” on page 49) and activating pin IRQ. The signal

on pin IRQ can be used to interrupt the microprocessor using its interrupt handling

capabilities ensuring efficient microprocessor software.

9.4.1 Interrupt sources overview

Table 19 shows the integrated interrupt flags, related source and setting condition. The

interrupt TimerIRq flag bit indicates an interrupt set by the timer unit. Bit TimerIRq is set

when the timer decrements from one down to zero (bit TAutoRestart disabled) or from one

to the TReLoadValue[7:0] with bit TAutoRestart enabled.

Bit TxIRq indicates interrupts from different sources and is set as follows:

• the transmitter automatically sets the bit TxIRq interrupt when it is active and its state

changes from sending data to transmitting the end of frame pattern

• the CRC coprocessor sets the bit TxIRq after all data from the FIFO buffer has been

processed indicated by bit CRCReady = logic 1

• when EEPROM programming is finished, the bit TxIRq is set and is indicated by bit

E2Ready = logic 1

The RxIRq flag bit indicates an interrupt when the end of the received data is detected.

The IdleIRq flag bit is set when a command finishes and the content of the Command

register changes to Idle.

When the FIFO buffer reaches the HIGH-level indicated by the WaterLevel[5:0] value (see

Section 9.3.3 on page 18) and bit HiAlert = logic 1, then the HiAlertIRq flag bit is set to

logic 1.

When the FIFO buffer reaches the LOW-level indicated by the WaterLevel[5:0] value (see

Section 9.3.3 on page 18) and bit LoAlert = logic 1, then LoAlertIRq flag bit is set to

logic 1.

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Table 19. Interrupt sources

Interrupt flag

TimerIRq

TxIRq

Interrupt source

timer unit

Trigger action

timer counts from 1 to 0

transmitter

a data stream, transmitted to the card, ends

all data from the FIFO buffer has been processed

CRC coprocessor

EEPROM

all data from the FIFO buffer has been

programmed

RxIRq

receiver

a data stream, received from the card, ends

command execution finishes

FIFO buffer is full

IdleIRq

Command register

FIFO buffer

HiAlertIRq

LoAlertIRq

FIFO buffer is empty

9.4.2 Interrupt request handling

9.4.2.1 Controlling interrupts and getting their status

The MFRC531 informs the microprocessor about the interrupt request source by setting

the relevant bit in the InterruptRq register. The relevance of each interrupt request bit as

source for an interrupt can be masked by the InterruptEn register interrupt enable bits.

Table 20. Interrupt control registers

Register

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

InterruptEn

InterruptRq

SetIEn

SetIRq

reserved

TimerIEn

TimerIRq

TxIEn

TxIRq

RxIEn

RxIRq

IdleIEn

IdleIRq

HiAlertIEn LoAlertIEn

HiAlertIRq LoAlertIRq

If any interrupt request flag is set to logic 1 (showing that an interrupt request is pending)

and the corresponding interrupt enable flag is set, the PrimaryStatus register IRq flag bit is

set to logic 1. Different interrupt sources can activate simultaneously because all interrupt

request bits are OR’ed, coupled to the IRq flag and then forwarded to pin IRQ.

9.4.2.2 Accessing the interrupt registers

The interrupt request bits are automatically set by the MFRC531’s internal state

machines. In addition, the microprocessor can also set or clear the interrupt request bits

as required.

A special implementation of the InterruptRq and InterruptEn registers enables changing

an individual bit status without influencing any other bits. If an interrupt register is set to

logic 1, bit SetIxx and the specific bit must both be set to logic 1 at the same time. If a

specific interrupt flag is cleared, zero must be written to the SetIxx and the interrupt

register address must be set to logic 1 at the same time.

If a content bit is not changed during the setting or clearing phase, zero must be written to

the specific bit location.

Example: Writing 3Fh to the InterruptRq register clears all bits. SetIRq is set to logic 0

while all other bits are set to logic 1. Writing 81h to the InterruptRq register sets LoAlertIRq

to logic 1 and leaves all other bits unchanged.

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9.4.3 Configuration of pin IRQ

The logic level of the IRq flag bit is visible on pin IRQ. The signal on pin IRQ can also be

controlled using the following IRQPinConfig register bits.

• bit IRQInv: the signal on pin IRQ is equal to the logic level of bit IRq when this bit is set

to logic 0. When set to logic 1, the signal on pin IRQ is inverted with respect to bit IRq.

• bit IRQPushPull: when set to logic 1, pin IRQ has CMOS output characteristics. When

it is set to logic 0, it is an open-drain output which requires an external resistor to

achieve a HIGH-level at pin IRQ.

Remark: During the reset phase (see Section 9.7.2 on page 28) bit IRQInv is set to

logic 1 and bit IRQPushPull is set to logic 0. This results in a high-impedance on pin IRQ.

9.4.4 Register overview interrupt request system

Table 21 shows the related interrupt request system flags in alphabetical order.

Table 21. Associated Interrupt request system registers and flags

Flags

Register name

InterruptEn

InterruptRq

InterruptEn

InterruptRq

PrimaryStatus

IRQPinConfig

InterruptEn

InterruptRq

InterruptEn

InterruptRq

InterruptEn

InterruptRq

InterruptEn

InterruptRq

InterruptEn

InterruptRq

Bit

1

2

3

1

0

3

7

5

4

Register address

HiAlertIEn

HiAlertIRq

IdleIEn

06h

07h

06h

07h

03h

07h

06h

07h

06h

07h

06h

07h

06h

07h

06h

07h

IdleIRq

IRq

IRQInv

IRQPushPull

LoAlertIEn

LoAlertIRq

RxIEn

RxIRq

SetIEn

SetIRq

TimerIEn

TimerIRq

TxIEn

TxIRq

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9.5 Timer unit

The timer derives its clock signal from the 13.56 MHz on-board chip clock. The

microprocessor can use this timer to manage timing-relevant tasks.

The timer unit can be used in one of the following configurations:

• Timeout counter

• WatchDog counter

• Stopwatch

• Programmable one shot

• Periodical trigger

The timer unit can be used to measure the time interval between two events or to indicate

that a specific timed event occurred. The timer is triggered by events but does not

influence any event (e.g. a time-out during data receiving does not automatically influence

the receiving process). Several timer related flags can be set and these flags can be used

to generate an interrupt.

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9.5.1 Timer unit implementation

9.5.1.1 Timer unit block diagram

Figure 8 shows the block diagram of the timer module.

TStartTxBegin

TxBegin Event

TStartTxEnd

TxEnd Event

TReloadValue[7:0]

PARALLEL IN

START COUNTER/

PARALLEL LOAD

TAutoRestart

TStartNow

TStopNow

Q

S

R

COUNTER MODULE

(x ≤ x − 1)

TRunning

STOP COUNTER

RxEnd Event

TStopRxEnd

RxBegin Event

TStopRxBegin

TPreScaler[4:0]

TimerValue[7:0]

CLOCK

DIVIDER

13.56 MHz

PARALLEL OUT

Counter = 0 ?

to parallel interface

to interrupt logic: TimerIRq

001aak611

Fig 8. Timer module block diagram

The timer unit is designed, so that events when combined with enabling flags start or stop

the counter. For example, setting bit TStartTxBegin = logic 1 enables control of received

data with the timer unit. In addition, the first received bit is indicated by the TxBegin event.

This combination starts the counter at the defined TReloadValue[7:0].

The timer stops automatically when the counter value is equal to zero or if a defined stop

event happens.

9.5.1.2 Controlling the timer unit

The main part of the timer unit is a down-counter. As long as the down-counter value is

not zero, it decrements its value with each timer clock cycle.

If the TAutoRestart flag is enabled, the timer does not decrement down to zero. On

reaching value 1, the timer reloads the next clock function with the TReloadValue[7:0].

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The timer is started immediately by loading a value from the TimerReload register into the

counter module.

This is activated by one of the following events:

• transmission of the first bit to the card (TxBegin event) with bit TStartTxBegin = logic 1

• transmission of the last bit to the card (TxEnd event) with bit TStartTxEnd = logic 1

• bit TStartNow is set to logic 1 by the microprocessor

Remark: Every start event reloads the timer from the TimerReload register. Thus, the

timer unit is re-triggered.

The timer can be configured to stop on one of the following events:

• receipt of the first valid bit from the card (RxBegin event) with bit

TStopRxBegin = logic 1

• receipt of the last bit from the card (RxEnd event) with bit TStopRxEnd = logic 1

• the counter module has decremented down to zero and bit TAutoRestart = logic 0

• bit TStopNow is set to logic 1 by the microprocessor.

Loading a new value, e.g. zero, into the TimerReload register or changing the timer unit

while it is counting will not immediately influence the counter. This is because this register

only affects the counter content after a start event.

If the counter is stopped when bit TStopNow is set, no TimerIRq is flagged.

9.5.1.3 Timer unit clock and period

The timer unit clock is derived from the 13.56 MHz on-board chip clock using the

programmable divider. Clock selection is made using the TimerClock register

TPreScaler[4:0] bits based on Equation 3:

2^TPreScaler

--------------------------

1

---------------------------

f_TimerClock

=

MHz

(3)

13.56

T_TimerClock

The values for the TPreScaler[4:0] bits are between 0 and 21 which results in a minimum

periodic time (T_TimerClock) of between 74 ns and 150 ms.

The time period elapsed since the last start event is calculated using Equation 4:

TReLoadValue – TimerValue

----------------------------------------------------------------------------

t_Timer

=

s

(4)

f_TimerClock

This results in a minimum time period (t_Timer) of between 74 ns and 40 s.

9.5.1.4 Timer unit status

The SecondaryStatus register’s TRunning bit shows the timer’s status. Configured start

events start the timer at the TReloadValue[7:0] and changes the status flag TRunning to

logic 1. Conversely, configured stop events stop the timer and set the TRunning status

flag to logic 0. As long as status flag TRunning is set to logic 1, the TimerValue register

changes on the next timer unit clock cycle.

The TimerValue[7:0] bits can be read directly from the TimerValue register.

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9.5.2 Using the timer unit functions

9.5.2.1 Time-out and WatchDog counters

After starting the timer using TReloadValue[7:0], the timer unit decrements the TimerValue

register beginning with a given start event. If a given stop event occurs, such as a bit

being received from the card, the timer unit stops without generating an interrupt.

If a stop event does not occur, such as the card not answering within the expected time,

the timer unit decrements down to zero and generates a timer interrupt request. This

signals to the microprocessor the expected event has not occurred within the given time

(t_Timer).

9.5.2.2 Stopwatch

The time (t_Timer) between a start and stop event is measured by the microprocessor using

the timer unit. Setting the TReloadValue register triggers the timer which in turn, starts to

decrement. If the defined stop event occurs, the timer stops. The time between start and

stop is calculated by the microprocessor using Equation 5, when the timer does not

decrement down to zero.

t = TReLoad_value– TimerValue  t_Timer

(5)

9.5.2.3 Programmable one shot timer and periodic trigger

Programmable one shot timer: The microprocessor starts the timer unit and waits for

the timer interrupt. The interrupt occurs after the time specified by t_Timer

.

Periodic trigger: If the microprocessor sets the TAutoRestart bit, it generates an interrupt

request after every t_Timercycle.

9.5.3 Timer unit registers

Table 22 shows the related flags of the timer unit in alphabetical order.

Table 22. Associated timer unit registers and flags

Flags

Register name

TimerClock

TimerValue

TimerReload

TimerClock

SecondaryStatus

Control

Bit

Register address

TAutoRestart

TimerValue[7:0]

TReloadValue[7:0]

TPreScaler[4:0]

TRunning

5

2Ah

0Ch

2Ch

2Ah

05h

09h

2Bh

09h

2Bh

7 to 0

4 to 0

7

1

0

1

2

3

TStartNow

TStartTxBegin

TStartTxEnd

TStopNow

TimerControl

Control

TStopRxBegin

TStopRxEnd

TimerControl

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9.6 Power reduction modes

9.6.1 Hard power-down

Hard power-down is enabled when pin RSTPD is HIGH. This turns off all internal current

sinks including the oscillator. All digital input buffers are separated from the input pads and

defined internally (except pin RSTPD itself). The output pins are frozen at a given value.

The status of all pins during a hard power-down is shown in Table 23.

Table 23. Signal on pins during Hard power-down

Symbol

OSCIN

IRQ

1

Type

Description

I

not separated from input, pulled to AVSS

high-impedance

2

O

I

MFIN

3

separated from input

LOW

MFOUT

TX1

4

O

5

HIGH, if bit TX1RFEn = logic 1

LOW, if bit TX1RFEn = logic 0

TX2

7

O

HIGH, only if bit TX2RFEn = logic 1 and bit

TX2Inv = logic 0

otherwise LOW

NCS

NWR

NRD

D0 to D7

ALE

9

I

separated from input

high-impedance

not changed

10

I

11

I

13 to 20

21

I/O

I

A0

22

I/O

I

A1

23

A2

24

I

AUX

27

O

I

RX

29

VMID

RSTPD

OSCOUT

30

A

I

pulled to V_DDA

31

not changed

32

O

HIGH

9.6.2 Soft power-down mode

Soft power-down mode is entered immediately using the Control register bit PowerDown.

All internal current sinks, including the oscillator buffer, are switched off. The digital input

buffers are not separated from the input pads and keep their functionality. In addition, the

digital output pins do not change their state.

After resetting the Control register bit PowerDown, the bit indicating Soft power-down

mode is only cleared after 512 clock cycles. Resetting it does not immediately clear it. The

PowerDown bit is automatically cleared when the Soft power-down mode is exited.

Remark: When the internal oscillator is used, time (t_osc) is required for the oscillator to

become stable. This is because the internal oscillator is supplied by V_DDAand any clock

cycles will not be detected by the internal logic until V_DDAis stable.

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9.6.3 Standby mode

The Standby mode is immediately entered when the Control register StandBy bit is set. All

internal current sinks, including the internal digital clock buffer are switched off. However,

the oscillator buffer is not switched off.

The digital input buffers are not separated by the input pads, keeping their functionality

and the digital output pins do not change their state. In addition, the oscillator does not

need time to wake-up.

After resetting the Control register StandBy bit, it takes four clock cycles on pin OSCIN for

Standby mode to exit. Resetting bit StandBy does not immediately clear it. It is

automatically cleared when the Standby mode is exited.

9.6.4 Automatic receiver power-down

It is a power saving feature to switch off the receiver circuit when it is not needed. Setting

bit RxAutoPD = logic 1, automatically powers down the receiver when it is not in use.

Setting bit RxAutoPD = logic 0, keeps the receiver continuously powered up.

9.7 StartUp phase

The events executed during the StartUp phase are shown in Figure 9.

StartUp phase

t

init

RSTPD

reset

Hard power-

down phase

Initialising

phase

states

Reset phase

ready

001aak613

Fig 9. The StartUp procedure

9.7.1 Hard power-down phase

The hard power-down phase is active during the following cases:

• a Power-On Reset (POR) caused by power-up on pins DVDD or AVDD activated

when V_DDDor V_DDAis below the digital reset threshold.

• a HIGH-level on pin RSTPD which is active while pin RSTPD is HIGH. The HIGH level

period on pin RSTPD must be at least 100 s (t_PD 100 s). Shorter phases will not

necessarily result in the reset phase (t_reset). The rising or falling edge slew rate on pin

RSTPD is not critical because pin RSTPD is a Schmitt trigger input.

Remark: In case two, HIGH level on pin RSTPD, has to be at least 100 s long (t_PD 100

s). Shorter phases will not necessarily result in the reset phase t_reset. The slew rate of

rising/falling edge on pin RSTPD is not critical because pin RSTPD is a Schmitt trigger

input.

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9.7.2 Reset phase

The reset phase automatically follows the Hard power-down. Once the oscillator is

running stably, the reset phase takes 512 clock cycles. During the reset phase, some

register bits are preset by hardware. The respective reset values are given in the

description of each register (see Section 10.5 on page 48).

Remark: When the internal oscillator is used, time (t_osc) is required for the oscillator to

become stable. This is because the internal oscillator is supplied by V_DDAand any clock

cycles will not be detected by the internal logic until V_DDAis stable.

9.7.3 Initialization phase

The initialization phase automatically follows the reset phase and takes 128 clock cycles.

During the initializing phase the content of the EEPROM blocks 1 and 2 is copied into the

register subaddresses 10h to 2Fh (see Section 9.2.2 on page 13).

Remark: During the production test, the MFRC531 is initialized with default configuration

values. This reduces the microprocessor’s configuration time to a minimum.

9.7.4 Initializing the parallel interface type

A different initialization sequence is used for each microprocessor. This enables detection

of the correct microprocessor interface type and synchronization of the microprocessor’s

and the MFRC531’s start-up. See Section 9.1.3 on page 8 for detailed information on the

different connections for each microprocessor interface type.

During StartUp phase, the command value is set to 3Fh once the oscillator attains clock

frequency stability at an amplitude of > 90 % of the nominal 13.56 MHz clock frequency. At

the end of the initialization phase, the MFRC531 automatically switches to idle and the

command value changes to 00h.

To ensure correct detection of the microprocessor interface, the following sequence is

executed:

• the Command register is read until the 6-bit register value is 00h. On reading the 00h

value, the internal initialization phase is complete and the MFRC531 is ready to be

controlled

• write 80h to the Page register to initialize the microprocessor interface

• read the Command register. If it returns a value of 00h, the microprocessor interface

was successfully initialized

• write 00h to the Page registers to activate linear addressing mode.

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9.8 Oscillator circuit

MFRC531

OSCOUT

OSCIN

13.56 MHz

15 pF

001aal224

Fig 10. Quartz clock connection

The clock applied to the MFRC531 acts as a time basis for the synchronous system

encoder and decoder. The stability of the clock frequency is an important factor for correct

operation. To obtain highest performance, clock jitter must be as small as possible. This is

best achieved by using the internal oscillator buffer with the recommended circuitry.

If an external clock source is used, the clock signal must be applied to pin OSCIN. In this

case, be very careful in optimizing clock duty cycle and clock jitter. Ensure the clock

quality has been verified. It must meet the specifications described in Section 13.4.5 on

page 97.

Remark: We do not recommend using an external clock source.

9.9 Transmitter pins TX1 and TX2

The signal on pins TX1 and TX2 is the 13.56 MHz energy carrier modulated by an

envelope signal. It can be used to drive an antenna directly, using minimal passive

components for matching and filtering (see Section 15.1 on page 98). To enable this, the

output circuitry is designed with a very low-impedance source resistance. The TxControl

register is used to control the TX1 and TX2 signals.

9.9.1 Configuring pins TX1 and TX2

TX1 pin configurations are described in Table 24.

Table 24. Pin TX1 configurations

TxControl register configuration

Envelope TX1 signal

TX1RFEn

FORCE100ASK

0

1

X

0

1

X

0

1

0

1

LOW (GND)

13.56 MHz carrier frequency modulated

13.56 MHz carrier frequency

LOW

13.56 MHz energy carrier

TX2 pin configurations are described in Table 25.

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Table 25. Pin TX2 configurations

TxControl register configuration

TX2RFEn FORCE100ASK TX2CW TX2Inv

Envelope TX2 signal

0

1

X

0

X

0

X

0

X

0

LOW

13.56 MHz carrier frequency

modulated

1

0

1

0

13.56 MHz carrier frequency

modulated, 180 phase-shift

relative to TX1

1

0

1

13.56 MHz carrier frequency,

180 phase-shift relative to TX1

1

0

1

0

1

X

13.56 MHz carrier frequency

13.56 MHz carrier frequency,

180 phase-shift relative to TX1

1

0

1

0

1

0

1

LOW

13.56 MHz carrier frequency

HIGH

13.56 MHz carrier frequency,

180 phase-shift relative to TX1

1

0

1

X

13.56 MHz carrier frequency

13.56 MHz carrier frequency,

180 phase-shift relative to TX1

9.9.2 Antenna operating distance versus power consumption

Using different antenna matching circuits (by varying the supply voltage on the antenna

driver supply pin TVDD), it is possible to find the trade-off between maximum effective

operating distance and power consumption. Different antenna matching circuits are

described in the Application note “MIFARE Design of MFRC500 Matching Circuit and

Antennas”.

9.9.3 Antenna driver output source resistance

The output source conductance of pins TX1 and TX2 can be adjusted between 1  and

100  using the CwConductance register GsCfgCW[5:0] bits.

The output source conductance of pins TX1 and TX2 during the modulation phase can be

adjusted between 1  and 100  using the ModConductance register GsCfgMod[5:0] bits.

The values are relative to the reference resistance (R_S(ref)) which is measured during the

production test and stored in the MFRC531 EEPROM. It can be read from the product

information field (see Section 9.2.1 on page 13). The electrical specification can be found

in Section 13.3.3 on page 92.

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9.9.3.1 Source resistance table

Table 26. TX1 and TX2 source resistance of n-channel driver transistor against GsCfgCW or GsCfgMod

MANT = Mantissa; EXP = Exponent.

GsCfgCW, EXP_GsCfgCW

GsCfgMod EXP_GsCfgModMANT_GsCfgMod()

,

MANT_GsCfgCW, R_S(ref)

GsCfgCW,

GsCfgMod

(decimal)

EXP_GsCfgCW

EXP_GsCfgMod

(decimal)

,

MANT_GsCfgCW

MANT_GsCfgMod()

(decimal)

,

R_S(ref)

(decimal)

0

(decimal)

0

1

2

3

0

1

0

2

1

0

1

0

3

2

1

0

1

0

2

1

0

1

0

3

2

0

-

24

25

37

26

27

51

38

28

29

39

30

52

31

40

41

53

42

43

54

44

45

55

46

47

56

57

58

59

60

61

62

63

1

2

1

3

2

1

2

1

3

1

2

3

2

3

2

3

2

3

8

9

0.0652

16

32

48

1

-

0.0580

0.0541

0.0522

0.0474

0.0467

0.0450

0.0435

0.0401

0.0386

0.0373

0.0350

0.0348

0.0338

0.0300

0.0280

0.0270

0.0246

0.0234

0.0225

0.0208

0.0200

0.0193

0.0180

0.0175

0.0156

0.0140

0.0127

0.0117

0.0108

0.0100

0.0093

0

-

5

0

-

10

11

3

1

1.0000

0.5217

0.5000

0.3333

0.2703

0.2609

0.2500

0.2000

0.1739

0.1667

0.1429

0.1402

0.1351

0.1304

0.1250

0.1111

0.1043

0.1000

0.0909

0.0901

0.0870

0.0833

0.0769

0.0745

0.0714

0.0701

0.0676

0.0667

17

2

1

2

6

3

12

13

7

33

18

4

1

2

4

14

4

5

19

6

3

15

8

6

7

9

49

34

20

8

1

5

2

10

11

6

4

8

9

12

13

7

21

10

11

35

22

12

13

23

14

50

36

15

5

10

11

3

14

15

8

6

12

13

7

9

10

11

12

13

14

15

14

2

4

15

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9.9.3.2 Calculating the relative source resistance

The reference source resistance R_S(ref)can be calculated using Equation 6.

1

R_Sref

=

(6)

--------------------------------------------------------------------------------

EXP

GsCfgCW

77





-----

MANT_GsCfgCW







40

The reference source resistance (R_S(ref)) during the modulation phase can be calculated

using ModConductance register’s GsCfgMod[5:0].

9.9.3.3 Calculating the effective source resistance

Wiring resistance (R_S(wire)): Wiring and bonding add a constant offset to the driver

resistance that is relevant when pins TX1 and TX2 are switched to low-impedance. The

additional resistance for pin TX1 (R_S(wire)TX1) can be set approximately as shown in

Equation 7.

R_{SwireTX1} 500 m

(7)

Effective resistance (R_Sx): The source resistances of the driver transistors (RsMaxP

byte) read from the Product Information Field (see Section 9.2.1 on page 13) are

measured during the production test with CwConductance register’s

GsCfgCW[5:0] = 01h.

To calculate the driver resistance for a specific value set in GsCfgMod[5:0], use

Equation 8.

R_Sx= R_{SrefmaxP}– R_{SwireTX1}  R_Srel+ R_{SwireTX1}

(8)

9.9.4 Pulse width

The envelope carries the data signal information that is transmitted to the card. It is an

encoded data signal based on the Miller code. In addition, each pause of the Miller

encoded signal is again encoded as a pulse of a fixed width. The width of the pulse is

adjusted using the ModWidth register. The pulse width (t_w) is calculated using Equation 9

where the frequency constant (f_clk) = 13.56 MHz.

ModWidth + 1

------------------------------------

t_w= 2

(9)

f_c

9.10 Receiver circuitry

The MFRC531 uses an integrated quadrature demodulation circuit enabling it to detect an

ISO/IEC 14443 A or ISO/IEC 14443 B compliant subcarrier signal on pin RX.

• ISO/IEC 14443 A subcarrier signal: defined as a Manchester coded ASK modulated

signal

• ISO/IEC 14443 B subcarrier signal: defined as an NRZ-L coded BPSK modulated

ISO/IEC 14443 B subcarrier signal

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The quadrature demodulator uses two different clocks (Q-clock and I-clock) with a

phase-shift of 90 between them. Both resulting subcarrier signals are amplified, filtered

and forwarded to the correlation circuitry. The correlation results are evaluated, digitized

and then passed to the digital circuitry. Various adjustments can be made to obtain

optimum performance for all processing units.

9.10.1 Receiver circuit block diagram

Figure 11 shows the block diagram of the receiver circuit. The receiving process can be

broken down in to several steps. Quadrature demodulation of the 13.56 MHz carrier signal

is performed. To achieve the optimum performance, automatic Q-clock calibration is

recommended (see Section 9.10.2.1 on page 33).

The demodulated signal is amplified by an adjustable amplifier. A correlation circuit

calculates the degree of similarity between the expected and the received signal. The

BitPhase register enables correlation interval position alignment with the received signal’s

bit grid. In the evaluation and digitizer circuitry, the valid bits are detected and the digital

results are sent to the FIFO buffer. Several tuning steps are possible for this circuit.

ClkQ180Deg

ClkQDelay[4:0]

ClkQCalib

I TO Q

CONVERSION

Gain[1:0]

CollLevel[3:0] RcvClkSell

MinLevel[3:0] RxWait[7:0]

clock

BitPhase[7:0]

I-clock

Q-clock

s_valid

EVALUATION

AND

DIGITIZER

CIRCUITRY

s_data

s_coll

CORRELATION

CIRCUITRY

13.56 MHz

DEMODULATOR

RX

s_clock

VRxFollQ

VRxAmpQ

VRxAmpI

VCorrDI

VCorrDQ

VCorrNQ

VEvalR

VRxFollI

VCorrNI

VEvalL

to

TestAnaOutSel

001aak615

Fig 11. Receiver circuit block diagram

The signal can be observed on its way through the receiver as shown in Figure 11. One

signal at a time can be routed to pin AUX using the TestAnaSelect register as described in

Section 15.2.2 on page 103.

9.10.2 Receiver operation

In general, the default settings programmed in the StartUp initialization file are suitable for

device to MIFARE card data communication. However, in some environments specific

user settings will achieve better performance.

9.10.2.1 Automatic Q-clock calibration

The quadrature demodulation concept of the receiver generates a phase signal (I-clock)

and a 90 phase-shifted quadrature signal (Q-clock). To achieve the optimum

demodulator performance, the Q-clock and the I-clock must be phase-shifted by 90. After

the reset phase, a calibration procedure is automatically performed.

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Automatic calibration can be set-up to execute at the end of each Transceive command if

bit ClkQCalib = logic 0. Setting bit ClkQCalib = logic 1 disables all automatic calibrations

except after the reset sequence. Automatic calibration can also be triggered by the

software when bit ClkQCalib has a logic 0 to logic 1 transition.

calibration impulse

a rising edge initiates

from reset sequence

Q-clock calibration

calibration impulse

from end of

Transceive command

ClkQCalib bit

001aak616

Fig 12. Automatic Q-clock calibration

Remark: The duration of the automatic Q-clock calibration is 65 oscillator periods or

approximately 4.8 s.

The ClockQControl register’s ClkQDelay[4:0] value is proportional to the phase-shift

between the Q-clock and the I-clock. The ClkQ180Deg status flag bit is set when the

phase-shift between the Q-clock and the I-clock is greater than 180.

Remark:

• The StartUp configuration file enables automatic Q-clock calibration after a reset

• If bit ClkQCalib = logic 1, automatic calibration is not performed. Leaving this bit set to

logic 1 can be used to permanently disable automatic calibration.

• It is possible to write data to the ClkQDelay[4:0] bits using the microprocessor. The

aim could be to disable automatic calibration and set the delay using the software.

Configuring the delay value using the software requires bit ClkQCalib to have been

previously set to logic 1 and a time interval of at least 4.8 s has elapsed. Each delay

value must be written with bit ClkQCalib set to logic 1. If bit ClkQCalib is logic 0, the

configured delay value is overwritten by the next automatic calibration interval.

9.10.2.2 Amplifier

The demodulated signal must be amplified by the variable amplifier to achieve the best

performance. The gain of the amplifiers can be adjusted using the RxControl1 register

Gain[1:0] bits; see Table 27.

Table 27. Gain factors for the internal amplifier

See Table 83 “RxControl1 register bit descriptions” on page 61 for additional information.

Register setting

Gain factor [dB]

(simulation results)

00

01

10

11

20

24

31

35

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9.10.2.3 Correlation circuitry

The correlation circuitry calculates the degree of matching between the received and an

expected signal. The output is a measure of the amplitude of the expected signal in the

received signal. This is done for both, the Q and I-channels. The correlator provides two

outputs for each of the two input channels, resulting in a total of four output signals.

The correlation circuitry needs the phase information for the incoming card signal for

optimum performance. This information is defined for the microprocessor using the

BitPhase register. This value defines the phase relationship between the transmitter and

receiver clock in multiples of the BitPhase time (t_BitPhase) = 1 / 13.56 MHz.

9.10.2.4 Evaluation and digitizer circuitry

The correlation results are evaluated for each bit-half of the Manchester coded signal. The

evaluation and digitizer circuit decides from the signal strengths of both bit-halves, if the

current bit is valid

• If the bit is valid, its value is identified

• If the bit is not valid, it is checked to identify if it contains a bit-collision

Select the following levels for optimal using RxThreshold register bits:

• MinLevel[3:0]: defines the minimum signal strength of the stronger bit-halve’s signal

which is considered valid.

• CollLevel[3:0]: defines the minimum signal strength relative to the amplitude of the

stronger half-bit that has to be exceeded by the weaker half-bit of the Manchester

coded signal to generate a bit-collision. If the signal’s strength is below this value,

logic 1 and logic 0 can be determined unequivocally.

After data transmission, the card is not allowed to send its response before a preset time

period which is called the frame guard time in the ISO/IEC 14443 standard. The length of

this time period is set using the RxWait register’s RxWait[7:0] bits. The RxWait register

defines when the receiver is switched on after data transmission to the card in multiples of

one bit duration.

If bit RcvClkSelI is set to logic 1, the I-clock is used to clock the correlator and evaluation

circuits. If bit RcvClkSelI is set to logic 0, the Q-clock is used.

Remark: It is recommended to use the Q-clock.

9.11 Serial signal switch

The MFRC531 comprises two main blocks:

• digital circuitry: comprising the state machines, encoder and decoder logic etc.

• analog circuitry: comprising the modulator, antenna drivers, receiver and

amplification circuitry

The interface between these two blocks can be configured so that the interface signals

are routed to pins MFIN and MFOUT. This makes it possible to connect the analog part of

one MFRC531 to the digital part of another device.

The serial signal switch can be used to measure MIFARE and ISO/IEC 14443 A.

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Remark: Pin MFIN can only be accessed at 106 kBd based on ISO/IEC 14443 A. The

Manchester signal and the Manchester signal with subcarrier can only be accessed on pin

MFOUT at 106 kBd based on ISO/IEC 14443 A.

9.11.1 Serial signal switch block diagram

Figure 13 shows the serial signal switches. Three different switches are implemented in

the serial signal switch enabling the MFRC531 to be used in different configurations.

The serial signal switch can also be used to check the transmitted and received data

during the design-in phase or for test purposes. Section 15.2.1 on page 101 describes the

analog test signals and measurements at the serial signal switch.

Remark: The SLR400 uses pin name SIGOUT for pin MFOUT. The MFRC531

functionality includes the test modes for the SLRC400 using pin MFOUT.

0

1

0

1

2

3

MILLER CODER

1 OUT OF 256

NRZ OR

TX1

TX2

envelope

MFIN

MODULATOR

DRIVER

serial data out

1 OUT OF 4

2

(part of)

analog circuitry

(part of)

serial data processing

Modulator

Source[1:0]

0

1

2

3

0

internal

Manchester out

SUBCARRIER

DEMODULATOR

CARRIER

DEMODULATOR

RX

MANCHESTER

DECODER

Manchester with subcarrier

Manchester

serial data in

2

SUBCARRIER

Decoder

DEMODULATOR

Source[1:0]

3

SERIAL SIGNAL SWITCH

MFOUTSelect[2:0]

digital test signal

signal to MFOUT

0

1

MFIN

MFOUT

001aak617

Fig 13. Serial signal switch block diagram

Section 9.11.2, Section 9.11.2.1 and Section 9.11.2.2 describe the relevant registers and

settings used to configure and control the serial signal switch.

9.11.2 Serial signal switch registers

The RxControl2 register DecoderSource[1:0] bits define the input signal for the internal

Manchester decoder and are described in Table 28.

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Standard ISO/IEC 14443 A/B reader solution

Table 28. DecoderSource[1:0] values

See Table 93 on page 64 for additional information.

Number DecoderSource Input signal to decoder

[1:0]

0

1

2

00

01

10

constant 0

output of the analog part. This is the default configuration

direct connection to pin MFIN; expects an 847.5 kHz subcarrier

signal modulated by a Manchester encoded signal

3

11

direct connection to pin MFIN; expects a Manchester encoded

signal

The TxControl register ModulatorSource[1:0] bits define the signal used to modulate the

transmitted 13.56 MHz energy carrier. The modulated signal drives pins TX1 and TX2.

Table 29. ModulatorSource[1:0] values

See Table 93 on page 64 for additional information.

Number ModulatorSource Input signal to modulator

[1:0]

0

1

2

00

01

10

constant 0 (energy carrier off on pins TX1 and TX2)

constant 1 (continuous energy carrier on pins TX1 and TX2)

modulation signal (envelope) from the internal encoder. This is the

default configuration.

3

11

direct connection to MFIN; expects a Miller pulse coded signal

The MFOUTSelect register MFOUTSelect[2:0] bits select the output signal which is to be

routed to pin MFOUT.

Table 30. MFOUTSelect[2:0] values

See Table 106 on page 67 for additional information.

Number MFOUTSelect Signal routed to pin MFOUT

[2:0]

0

1

2

3

000

001

010

011

constant LOW

constant HIGH

modulation signal (envelope) from the internal encoder

serial data stream to be transmitted; the same as for

MFOUTSelect[2:0] = 001 but not encoded by the selected pulse

encoder

4

5

100

101

output signal of the receiver circuit; card modulation signal

regenerated and delayed

output signal of the subcarrier demodulator; Manchester coded card

signal

6

7

110

111

reserved

To use the MFOUTSelect[2:0] bits, the TestDigiSelect register SignalToMFOUT bit must

be logic 0.

9.11.2.1 Active antenna concept

The MFRC531 analog and digital circuitry is accessed using pins MFIN and MFOUT.

Table 31 lists the required settings.

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Table 31. Register settings to enable use of the analog circuitry

Register

Number^[1]Signal

Analog circuitry settings

MFRC531 pin

ModulatorSource

MFOUTSelect

3

4

X

Miller pulse encoded

MFIN

MFOUT

-

Manchester encoded with subcarrier

-

DecoderSource

Digital circuitry settings

ModulatorSource

MFOUTSelect

X

2

-

Miller pulse encoded

MFOUT

MFIN

DecoderSource

Manchester encoded with subcarrier

[1] The number column refers to the value in the number column of Table 28, Table 29 and Table 30.

Two MFRC531 devices configured as described in Table 31 can be connected to each

other using pins MFOUT and MFIN.

Remark: The active antenna concept can only be used at 106 kBd based on

ISO/IEC 14443 A.

9.11.2.2 Driving both RF parts

It is possible to connect both passive and active antennas to a single IC. The passive

antenna pins TX1, TX2 and RX are connected using the appropriate filter and matching

circuit. At the same time an active antenna is connected to pins MFOUT and MFIN. In this

configuration, two RF parts can be driven, one after another, by one microprocessor.

9.12 MIFARE higher baud rates

The MIFARE system is specified with a fixed baud rate of 106 kBd for communication on

the RF interface. The current version of ISO/IEC 14443 A also defines 106 kBd for the

initial phase of a communication between Proximity Integrated Circuit Cards (PICC) and

Proximity Coupling Devices (PCD).

To cover requirements of large data transmissions and to speed up terminal to card

communication, the MFRC531 supports communication at MIFARE higher baud rates in

combination with a microcontroller IC such as the MIFARE ProX.

Table 32. MIFARE higher baud rates

Communication direction

Baud rates (kBd)

MFRC531 based PCD  microcontroller PICC supporting higher baud rates 106, 212, 424

Microcontroller PICC supporting higher baud rates  MFRC531 based PCD 106, 212, 424

The MIFARE higher baud rates concept is described in the application note: MIFARE

Implementation of Higher Baud rates Ref. 5. This application note covers the integration

of the MIFARE higher baud rates communication concept in current applications.

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9.13 ISO/IEC 14443 B communication scheme

The international standard ISO/IEC 14443 covers two communication schemes;

ISO/IEC 14443 A and ISO/IEC 14443 B. The MFRC531 reader IC fully supports both

ISO/IEC 14443 variants.

Table 33 describes the registers and flags covered by the ISO/IEC 14443 B

communication protocol.

Table 33. ISO/IEC 14443 B registers and flags

Flag

Register

Bit

Register address

CharSpacing[2:0]

CoderRate[2:0]

EOFWidth

TypeBFraming

CoderControl

4 to 2

5 to 3

5

17h

14h

17h

1Dh

11h

12h

13h

1Ch

17h

1Dh

1Ah

17h

19h

1Dh

14h

TypeBFraming

BPSKDemControl

TxControl

FilterAmpDet

Force100ASK

GsCfgCW[5:0]

GsCfgMod[5:0]

MinLevel[3:0]

NoTxEOF

4

CwConductance

ModConductance

RxThreshold

5 to 0

7 to 4

6

TypeBFraming

BPSKDemControl

DecoderControl

TypeBFraming

RxControl1

NoTxSOF

7

NoRxEGT

6

NoRxEOF

5

NoRxSOF

7

RxCoding

0

RxFraming[1:0]

SOFWidth[1:0]

SubCPulses[2:0]

TauB[1:0]

4 to 3

1 to 0

7 to 5

1 to 0

3 to 2

2 to 0

BPSKDemControl

CoderControl

TauD[1:0]

TxCoding[2:0]

As reference documentation, the international standard ISO/IEC 14443 Identification

cards - Contactless integrated circuit(s) cards - Proximity cards, part 1-4 (Ref. 4) can be

used.

Remark: NXP Semiconductors does not offer a basic function library to design-in the

ISO/IEC 14443 B protocol.

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9.14 MIFARE authentication and Crypto1

The security algorithm used in the MIFARE products is called Crypto1. It is based on a

proprietary stream cipher with a 48-bit key length. To access data on MIFARE cards,

knowledge of the key format is needed. The correct key must be available in the

MFRC531 to enable successful card authentication and access to the card’s data stored

in the EEPROM.

After a card is selected as defined in ISO/IEC 14443 A standard, the user can continue

with the MIFARE protocol. It is mandatory that card authentication is performed.

Crypto1 authentication is a 3-pass authentication which is automatically performed when

the Authent1 and Authent2 commands are executed (see Section 11.6.3 on page 89 and

Section 11.6.4 on page 89).

During the card authentication procedure, the security algorithm is initialized. After a

successful authentication, communication with the MIFARE card is encrypted.

9.14.1 Crypto1 key handling

On execution of the authentication command, the MFRC531 reads the key from the key

buffer. The key is always read from the key buffer and ensures Crypto1 authentication

commands do not require addressing of a key. The user must ensure the correct key is

prepared in the key buffer before triggering card authentication.

The key buffer can be loaded from:

• the EEPROM using the LoadKeyE2 command (see Section 11.6.1 on page 88)

• the microprocessor’s FIFO buffer using the LoadKey command (see Section 11.6.2

on page 88). This is shown in Figure 14.

WriteE2

EEPROM

KEYS

from the microcontroller

FIFO BUFFER

LoadKey

LoadKeyE2

KEY BUFFER

during

Authent1

serial data stream in

(plain)

serial data stream out

CRYPTO1

MODULE

(encrypted)

001aak624

Fig 14. Crypto1 key handling block diagram

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9.14.2 Authentication procedure

The Crypto1 security algorithm enables authentication of MIFARE cards. To obtain valid

authentication, the correct key has to be available in the key buffer of the MFRC531. This

can be ensured as follows:

1. Load the internal key buffer by using the LoadKeyE2 (see Section 11.6.1 on page 88)

or the LoadKey (see Section 11.6.2 on page 88) commands.

2. Start the Authent1 command (see Section 11.6.3 on page 89). When finished, check

the error flags to obtain the command execution status.

3. Start the Authent2 command (see Section 11.6.4 on page 89). When finished, check

the error flags and bit Crypto1On to obtain the command execution status.

10. MFRC531 registers

10.1 Register addressing modes

Three methods can be used to operate the MFRC531:

• initiating functions and controlling data by executing commands

• configuring the functional operation using a set of configuration bits

• monitoring the state of the MFRC531 by reading status flags

The commands, configuration bits and flags are accessed using the microprocessor

interface. The MFRC531 can internally address 64 registers using six address lines.

10.1.1 Page registers

The MFRC531 register set is segmented into eight pages contain eight registers each. A

Page register can always be addressed, irrespective of which page is currently selected.

10.1.2 Dedicated address bus

When using the MFRC531 with the dedicated address bus, the microprocessor defines

three address lines using address pins A0, A1 and A2. This enables addressing within a

page. To switch between registers in different pages a paging mechanism needs to be

used.

Table 34 shows how the register address is assembled.

Table 34. Dedicated address bus: assembling the register address

Register bit: UsePageSelect

Register address

PageSelect2 PageSelect1

1

PageSelect0

A2 A1 A0

10.1.3 Multiplexed address bus

The microprocessor may define all six address lines at once using the MFRC531 with a

multiplexed address bus. In this case, either the paging mechanism or linear addressing

can be used.

Table 35 shows how the register address is assembled.

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Table 35. Multiplexed address bus: assembling the register address

Multiplexed UsePage Register address

address bus type

Select

Paging mode

1

0

PageSelect2 PageSelect1 PageSelect0 AD2 AD1 AD0

AD5 AD4 AD3 AD2 AD1 AD0

Linear addressing

10.2 Register bit behavior

Bits and flags for different registers behave differently, depending on their functions. In

principle, bits with same behavior are grouped in common registers. Table 36 describes

the function of the Access column in the register tables.

Table 36. Behavior and designation of register bits

Abbreviation Behavior

R/W read and write

Description

These bits can be read and written by the microprocessor.

Since they are only used for control, their content is not

influenced by internal state machines.

Example: TimerReload register may be read and written by

the microprocessor. It will also be read by internal state

machines but never changed by them.

D

dynamic

These bits can be read and written by the microprocessor.

Nevertheless, they may also be written automatically by

internal state machines.

Example: the Command register changes its value

automatically after the execution of the command.

R

read only

write only

These registers hold flags which have a value determined by

internal states only.

Example: the ErrorFlag register cannot be written externally

but shows internal states.

W

These registers are used for control only. They may be written

by the microprocessor but cannot be read. Reading these

registers returns an undefined value.

Example: The TestAnaSelect register is used to determine the

signal on pin AUX however, it is not possible to read its

content.

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10.3 Register overview

Table 37. MFRC531 register overview

Sub

Register name

Function

Refer to

address

(Hex)

Page 0: Command and status

00h

01h

02h

03h

04h

05h

06h

07h

Page

selects the page register

Table 39 on page 48

Table 41 on page 48

Command

FIFOData

starts and stops command execution

input and output for the 64-byte FIFO buffer

receiver, transmitter and FIFO buffer status flags

number of bytes buffered in the FIFO buffer

secondary status flags

Table 43 on page 49

Table 45 on page 49

Table 47 on page 50

Table 49 on page 51

Table 51 on page 51

Table 53 on page 52

PrimaryStatus

FIFOLength

SecondaryStatus

InterruptEn

InterruptRq

enable and disable interrupt request control bits

interrupt request flags

Page 1: Control and status

08h

09h

0Ah

0Bh

0Ch

0Dh

0Eh

0Fh

Page

selects the page register

Table 39 on page 48

Table 55 on page 53

Table 57 on page 53

Control

control flags for timer unit, power saving etc

show the error status of the last command executed

ErrorFlag

CollPos

bit position of the first bit-collision detected on the RF interface Table 59 on page 54

TimerValue

CRCResultLSB

CRCResultMSB

BitFraming

value of the timer

Table 61 on page 55

Table 63 on page 55

Table 65 on page 55

Table 67 on page 56

LSB of the CRC coprocessor register

MSB of the CRC coprocessor register

adjustments for bit oriented frames

Page 2: Transmitter and coder control

10h

11h

12h

13h

14h

15h

16h

17h

Page

selects the page register

Table 39 on page 48

Table 69 on page 57

TxControl

controls the operation of the antenna driver pins TX1 and TX2

CwConductance

ModConductance

CoderControl

ModWidth

selects the conductance of the antenna driver pins TX1 and TX2 Table 71 on page 58

defines the driver output conductance

Table 73 on page 58

Table 75 on page 59

Table 77 on page 59

Table 79 on page 59

Table 80 on page 60

sets the clock frequency and the encoding

selects the modulation pulse width

ModWidthSOF

TypeBFraming

selects the SOF pulse-width modulation

defines the framing for ISO/IEC 14443 B communication

Page 3: Receiver and decoder control

18

Page

selects the page register

Table 39 on page 48

Table 82 on page 61

Table 84 on page 62

Table 86 on page 62

Table 88 on page 63

Table 90 on page 63

Table 92 on page 64

Table 94 on page 64

19

RxControl1

DecoderControl

BitPhase

controls receiver behavior

1A

1B

1C

1D

1Eh

1Fh

controls decoder behavior

selects the bit-phase between transmitter and receiver clock

selects thresholds for the bit decoder

controls BPSK receiver behavior

RxThreshold

BPSKDemControl

RxControl2

ClockQControl

controls decoder and defines the receiver input source

clock control for the 90 phase-shifted Q-channel clock

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Table 37. MFRC531 register overview …continued

Sub

Register name

Function

Refer to

address

(Hex)

Page 4: RF Timing and channel redundancy

20h

21h

22h

Page

selects the page register

Table 39 on page 48

RxWait

selects the interval after transmission before the receiver starts Table 96 on page 65

ChannelRedundancy selects the method and mode used to check data integrity on

the RF channel

Table 98 on page 65

23h

24h

25h

26h

CRCPresetLSB

CRCPresetMSB

PreSet25

preset LSB value for the CRC register

preset MSB value for the CRC register

these values are not changed

Table 100 on page 66

Table 102 on page 66

MFOUTSelect

selects internal signal applied to pin MFOUT, includes the MSB Table 104 on page 66

of TimeSlotPeriod value; see Table 105 on page 67

27h

PreSet27

these values are not changed

Table 107 on page 67

Page 5: FIFO, timer and IRQ pin configuration

28h

29h

2Ah

2Bh

2Ch

2Dh

2Eh

2Fh

Page

selects the page register

Table 39 on page 48

FIFOLevel

TimerClock

TimerControl

TimerReload

IRQPinConfig

PreSet2E

defines the FIFO buffer overflow and underflow warning levels Table 47 on page 50

selects the timer clock divider

selects the timer start and stop conditions

defines the timer preset value

configures pin IRQ output stage

these values are not changed

Table 110 on page 68

Table 112 on page 69

Table 114 on page 69

Table 116 on page 70

Table 118 on page 70

Table 119 on page 70

PreSet2F

Page 6: reserved registers

30h

31h

32h

33h

34h

35h

36h

37h

Page

selects the page register

reserved

Table 39 on page 48

Table 120 on page 70

reserved

Page 7: Test control

38h

39h

3Ah

3Bh

3Ch

3Dh

3Eh

3Fh

Page

selects the page register

reserved

Table 39 on page 48

Table 121 on page 71

Table 122 on page 71

Table 124 on page 72

Table 125 on page 72

Table 126 on page 72

Table 128 on page 73

reserved

TestAnaSelect

reserved

selects analog test mode

reserved

TestDigiSelect

reserved

selects digital test mode

reserved

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10.4 MFRC531 register flags overview

Table 38. MFRC531 register flags overview

Flag(s)

Register

Bit

Address

AccessErr

ErrorFlag

5

0Ah

BitPhase[7:0]

CharSpacing[2:0]

ClkQ180Deg

ClkQCalib

BitPhase

7 to 0 1Bh

4 to 2 17h,

TypeBFraming

ClockQControl

CoderControl

ErrorFlag

7

6

1Fh

ClkQDelay[4:0]

CoderRate[2:0]

CollErr

4 to 0 1Fh

5 to 3 14h

0

0Ah

CollLevel[3:0]

CollPos[7:0]

Command[5:0]

CRC3309

RxThreshold

CollPos

3 to 0 1Ch

7 to 0 0Bh

5 to 0 01h

Command

ChannelRedundancy

ErrorFlag

5

4

3

22h

0Ah

CRC8

CRCErr

CRCPresetLSB[7:0]

CRCPresetMSB[7:0]

CRCReady

CRCResultMSB[7:0]

CRCResultLSB[7:0]

Crypto1On

CRCPresetLSB

CRCPresetMSB

SecondaryStatus

CRCResultMSB

CRCResultLSB

Control

7 to 0 23h

7 to 0 24h

5

05h

7 to 0 0Eh

7 to 0 0Dh

3

09h

DecoderSource[1:0]

E2Ready

RxControl2

1 to 0 1Eh

SecondaryStatus

TypeBFraming

PrimaryStatus

FIFOData

6

5

2

05h

17h

03h

EOFWidth

Err

FIFOData[7:0]

FIFOLength[6:0]

FIFOOvfl

7 to 0 02h

6 to 0 04h

FIFOLength

ErrorFlag

4

0

4

2

0Ah

1Dh

09h

11h

0Ah

FilterAmpDet

FlushFIFO

BPSKDemControl

Control

Force100ASK

FramingErr

Gain[1:0]

TxControl

ErrorFlag

RxControl1

1 to 0 19h

5 to 0 12h

5 to 0 13h

GsCfgCW[5:0]

GsCfgMod[5:0]

HiAlert

CwConductance

ModConductance

PrimaryStatus

InterruptEn

1

2

03h

06h

07h

06h

07h

HiAlertIEn

HiAlertIRq

InterruptRq

IdleIEn

InterruptEn

IdleIRq

InterruptRq

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Table 38. MFRC531 register flags overview …continued

Flag(s)

Register

Bit

7

Address

01h

IFDetectBusy

IRq

Command

PrimaryStatus

IRQPinConfig

RxControl1

3

03h

IRQInv

1

2Dh

IRQPushPull

ISO Selection[1:0]

KeyErr

0

2Dh

4 to 3 19h

ErrorFlag

6

0

2

0Ah

03h

06h

07h

19h

LoAlert

PrimaryStatus

InterruptEn

LoAlertIEn

LoAlertIRq

InterruptRq

LPOff

RxControl1

MFOUTSelect[2:0]

MinLevel[3:0]

ModemState[2:0]

ModulatorSource[1:0]

ModWidth[7:0]

NoRxEGT

MFOUTSelect

RxThreshold

PrimaryStatus

TxControl

2 to 0 26h

7 to 4 1Ch

6 to 4 03h

6 to 5 11h

7 to 0 15h

ModWidth

BPSKDemControl

TypeBFraming

Page

6

5

7

6

7

1Dh

17h

NoRxEOF

NoRxSOF

NoTxEOF

NoTxSOF

PageSelect[2:0]

2 to 0 00h, 08h, 10h, 18h, 20h, 28h, 30h

and 38h

ParityEn

ChannelRedundancy

ErrorFlag

0

1

4

7

22h

0Ah

22h

09h

1Eh

ParityErr

ParityOdd

PowerDown

RcvClkSelI

RxAlign[2:0]

RxAutoPD

RxCRCEn

RxCoding

RxFraming[1:0]

RxIEn

ChannelRedundancy

Control

RxControl2

BitFraming

6 to 4 0Fh

RxControl2

6

3

0

1Eh

22h

1Ah

ChannelRedundancy

DecoderControl

InterruptEn

4 to 3 1Ah

3

06h

07h

RxIRq

InterruptRq

RxLastBits[2:0]

RxMultiple

RxWait[7:0]

SetIEn

SecondaryStatus

DecoderControl

RxWait

2 to 0 05h

1Ah

7 to 0 21h

6

InterruptEn

7

06h

07h

3Dh

SetIRq

InterruptRq

SignalToMFOUT

SOFWidth[1:0]

TestDigiSelect

TypeBFraming

1 to 0 17h

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Table 38. MFRC531 register flags overview …continued

Flag(s)

Register

Bit

Address

StandBy

Control

5

09h

SubCPulses[2:0]

TauB[1:0]

RxControl1

BPSKDemControl

TimerClock

TestAnaSelect

TestDigiSelect

InterruptEn

InterruptRq

TimerValue

TimeSlotPeriod

MFOUTSelect

TimerClock

TimerReload

SecondaryStatus

TimerControl

Control

7 to 5 19h

1 to 0 1Dh

3 to 2 1Dh

TauD[1:0]

TAutoRestart

TestAnaOutSel[4:0]

TestDigiSignalSel[6:0]

TimerIEn

5

2Ah

3 to 0 3Ah

6 to 0 3Dh

5

06h

07h

TimerIRq

TimerValue[7:0]

TimeSlotPeriod[7:0]

TimeSlotPeriodMSB

TPreScaler[4:0]

TReloadValue[7:0]

TRunning

7 to 0 0Ch

7 to 0 25h

4

26h

4 to 0 2Ah

7 to 0 2Ch

7

0

1

2

3

2

0

3

1

05h

2Bh

09h

2Bh

09h

11h

TStartTxBegin

TStartTxEnd

TStartNow

TStopRxBegin

TStopRxEnd

TStopNow

TimerControl

Control

TX1RFEn

TxControl

TX2Cw

TxControl

TX2Inv

TxControl

TX2RFEn

TxControl

TxCoding[2:0]

TxCRCEn

CoderControl

ChannelRedundancy

InterruptEn

InterruptRq

BitFraming

2 to 0 14h

2

4

22h

06h

07h

TxIEn

TxIRq

TxLastBits[2:0]

UsePageSelect

2 to 0 0Fh

00h, 08h, 10h, 18h, 20h, 28h, 30h

and 38h

5 to 0 29h

1Ah, bit 5

Page

7

WaterLevel[5:0]

ZeroAfterColl

FIFOLevel

DecoderControl

7

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10.5 Register descriptions

10.5.1 Page 0: Command and status

10.5.1.1 Page register

Selects the page register.

Table 39. Page register (address: 00h, 08h, 10h, 18h, 20h, 28h, 30h, 38h)

reset value: 1000 0000b, 80h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

UsePageSelect

R/W

0000

R/W

PageSelect[2:0]

R/W

Table 40. Page register bit descriptions

Bit

Symbol

Value Description

7

UsePageSelect

1

the value of PageSelect[2:0] is used as the register address

A5, A4, and A3. The LSBs of the register address are

defined using the address pins or the internal address latch,

respectively.

0

-

the complete content of the internal address latch defines

the register address. The address pins are used as

described in Table 5 on page 8.

6 to 3

2 to 0

0000

reserved

PageSelect[2:0] -

when UsePageSelect = logic 1, the value of PageSelect is

used to specify the register page (A5, A4 and A3 of the

register address)

10.5.1.2 Command register

Starts and stops the command execution.

Table 41. Command register (address: 01h) reset value: x000 0000b, x0h bit allocation

Bit

7

IFDetectBusy

R

6

0

5

4

3

2

1

0

Symbol

Access

Command[5:0]

D

R

Table 42. Command register bit descriptions

Bit

Symbol

Value Description

7

IFDetectBusy

-

shows the status of interface detection logic

interface detection finished successfully

interface detection ongoing

reserved

0

1

-

6

0

5 to 0

Command[5:0]

-

activates a command based on the Command code.

Reading this register shows which command is being

executed.

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10.5.1.3 FIFOData register

Input and output of the 64 byte FIFO buffer.

Table 43. FIFOData register (address: 02h) reset value: xxxx xxxxb, 05h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

FIFOData[7:0]

D

Table 44. FIFOData register bit descriptions

Bit

Symbol

Description

7 to 0

FIFOData[7:0] data input and output port for the internal 64-byte FIFO buffer. The FIFO

buffer acts as a parallel in to parallel out converter for all data streams.

10.5.1.4 PrimaryStatus register

Bits relating to receiver, transmitter and FIFO buffer status flags.

Table 45. PrimaryStatus register (address: 03h) reset value: 0000 0101b, 05h bit allocation

Bit

7

0

6

5

4

3

IRq

R

2

Err

R

1

HiAlert

R

0

LoAlert

R

Symbol

Access

ModemState[2:0]

R

Table 46. PrimaryStatus register bit descriptions

Bit

Symbol

Value Status

Description

7

0

-

reserved

6 to 4 ModemState[2:0]

shows the state of the transmitter and receiver

state machines:

000

Idle

neither the transmitter or receiver are operating;

neither of them are started or have input data

001

010

TxSOF

TxData

transmit start of frame pattern

transmit data from the FIFO buffer (or

redundancy CRC check bits)

011

100

TxEOF

transmit End Of Frame (EOF) pattern

GoToRx1

GoToRx2

PrepareRx

intermediate state 1; receiver starts

intermediate state 2; receiver finishes

101

110

waiting until the RxWait register time period

expires

AwaitingRx

Receiving

receiver activated; waiting for an input signal on

pin RX

111

-

receiving data

3

IRq

shows any interrupt source requesting attention

based on the InterruptEn register flag settings

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Table 46. PrimaryStatus register bit descriptions …continued

Bit

2

Symbol

Err

Value Status

Description

1

any error flag in the ErrorFlag register is set

1

HiAlert

the alert level for the number of bytes in the FIFO

buffer (FIFOLength[6:0]) is:

HiAlert = 64 – FIFOLength  WaterLevel

otherwise value = logic 0

Example:

FIFOLength = 60, WaterLevel = 4 then

HiAlert = logic 1

FIFOLength = 59, WaterLevel = 4 then

HiAlert = logic 0

0

LoAlert

1

the alert level for number of bytes in the FIFO

buffer (FIFOLength[6:0]) is:

LoAlert = FIFOLength  WaterLevel otherwise

value = logic 0

Example:

FIFOLength = 4, WaterLevel = 4 then

LoAlert = logic 1

FIFOLength = 5, WaterLevel = 4 then

LoAlert = logic 0

10.5.1.5 FIFOLength register

Number of bytes in the FIFO buffer.

Table 47. FIFOLength register (address: 04h) reset value: 0000 0000b, 00h bit allocation

Bit

7

0

6

5

4

3

2

1

0

Symbol

Access

FIFOLength[6:0]

R

Table 48. FIFOLength bit descriptions

Bit

Symbol

Description

7

0

reserved

6 to 0 FIFOLength[6:0]

gives the number of bytes stored in the FIFO buffer. Writing

increments the FIFOLength register value while reading decrements

the FIFOLength register value

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10.5.1.6 SecondaryStatus register

Various secondary status flags.

Table 49. SecondaryStatus register (address: 05h) reset value: 01100 000b, 60h bit

allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

TRunning E2Ready CRCReady

00

R

RxLastBits[2:0]

R

Table 50. SecondaryStatus register bit descriptions

Bit

Symbol

Value Description

7

TRunning

1

the timer unit is running and the counter decrements the

TimerValue register on the next timer clock cycle

0

1

0

1

0

-

the timer unit is not running

EEPROM programming is finished

EEPROM programming is ongoing

CRC calculation is finished

CRC calculation is ongoing

reserved

6

5

E2Ready

CRCReady

4 to 3 00

2 to 0 RxLastBits[2:0]

-

shows the number of valid bits in the last received byte. If zero,

the whole byte is valid

10.5.1.7 InterruptEn register

Control bits to enable and disable passing of interrupt requests.

Table 51. InterruptEn register (address: 06h) reset value: 0000 0000b, 00h bit allocation

Bit

7

SetIEn

W

6

0

5

4

3

2

1

0

Symbol

Access

TimerIEn

R/W

TxIEn

R/W

RxIEn IdleIEn HiAlertIEn LoAlertIEn

R/W R/W R/W R/W

R/W

Table 52. InterruptEn register bit descriptions

Bit Symbol Value Description

7

SetIEn

1

0

-

indicates that the marked bits in the InterruptEn register are set

clears the marked bits

6

5

4

3

2

1

0

reserved

TimerIEn

TxIEn

-

sends the TimerIRq timer interrupt request to pin IRQ^[1]

sends the TxIRq transmitter interrupt request to pin IRQ^[1]

sends the RxIRq receiver interrupt request to pin IRQ^[1]

sends the IdleIRq idle interrupt request to pin IRQ^[1]

sends the HiAlertIRq high alert interrupt request to pin IRQ^[1]

sends the LoAlertIRq low alert interrupt request to pin IRQ^[1]

-

RxIEn

IdleIEn

HiAlertIEn

-

LoAlertIEn -

[1] This bit can only be set or cleared using bit SetIEn.

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10.5.1.8 InterruptRq register

Interrupt request flags.

Table 53. InterruptRq register (address: 07h) reset value: 0000 0000b, 00h bit allocation

Bit

7

SetIRq

W

6

0

5

TimerIRq

D

4

TxIRq

D

3

2

1

0

Symbol

Access

RxIRq IdleIRq HiAlertIRq LoAlertIRq

R/W

D

Table 54. InterruptRq register bit descriptions

Bit Symbol Value Description

7

SetIRq

1

0

-

sets the marked bits in the InterruptRq register

clears the marked bits in the InterruptRq register

reserved

6

5

0

TimerIRq

1

0

1

timer decrements the TimerValue register to zero

timer decrements are still greater than zero

4

TxIRq

TxIRq is set to logic 1 if one of the following events occurs:

Transceive command; all data transmitted

Authent1 and Authent2 commands; all data transmitted

WriteE2 command; all data is programmed

CalcCRC command; all data is processed

0

when not acted on by Transceive, Authent1, Authent2, WriteE2 or

CalcCRC commands

3

2

RxIRq

1

0

1

the receiver terminates

reception still ongoing

IdleIRq

command terminates correctly. For example; when the Command

register changes its value from any command to the Idle command.

If an unknown command is started the IdleIRq bit is set.

Microprocessor start-up of the Idle command does not set the

IdleIRq bit.

0

1

0

1

0

IdleIRq = logic 0 in all other instances

PrimaryStatus register HiAlert bit is set^[1]

PrimaryStatus register HiAlert bit is not set

PrimaryStatus register LoAlert bit is set^[1]

PrimaryStatus register LoAlert bit is not set

1

0

HiAlertIRq

LoAlertIRq

[1] PrimaryStatus register Bit HiAlertIRq stores this event and it can only be reset using bit SetIRq.

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10.5.2 Page 1: Control and status

10.5.2.1 Page register

Selects the page register; see Section 10.5.1.1 “Page register” on page 48.

10.5.2.2 Control register

Various control flags, for timer, power saving, etc.

Table 55. Control register (address: 09h) reset value: 0000 0000b, 00h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

00

StandBy PowerDown Crypto1On TStopNow TStartNow FlushFIFO

R/W

D

Table 56. Control register bit descriptions

Bit Symbol Value Description

7 to 6 00

-

reserved

5

4

3

StandBy

1

activates Standby mode. The current consuming blocks are

switched off but the clock keeps running

PowerDown

Crypto1On

1

activates Power-down mode. The current consuming blocks

are switched off including the clock

Crypto1 unit is switched on and all data communication with

the card is encrypted. This bit can only be set to logic 1 by

successful execution of the Authent2 command

0

1

Crypto1 unit is switched off. All data communication with the

card is unencrypted (plain)

2

1

0

TStopNow

TStartNow

FlushFIFO

immediately stops the timer. Reading this bit always returns

logic 0

immediately starts the timer. Reading this bit will always

returns logic 0

immediately clears the internal FIFO buffer’s read and write

pointer, the FIFOLength[6:0] bits and FIFOOvfl flag are set to

logic 0. Reading this bit always returns logic 0

10.5.2.3 ErrorFlag register

Error flags show the error status of the last executed command.

Table 57. ErrorFlag register (address: 0Ah) reset value: 0100 0000b, 40h bit allocation

Bit

7

0

6

5

4

3

2

1

0

Symbol

Access

KeyErr AccessErr FIFOOvfl CRCErr FramingErr ParityErr CollErr

R

Table 58. ErrorFlag register bit descriptions

Bit Symbol Value Description

7

6

0

-

reserved

KeyErr

1

set when the LoadKeyE2 or LoadKey command recognize that the

input data is not encoded based on the Key format definition

0

set when the LoadKeyE2 or the LoadKey command starts

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Table 58. ErrorFlag register bit descriptions …continued

Bit Symbol Value Description

5

AccessErr

1

0

1

set when the access rights to the EEPROM are violated

set when an EEPROM related command starts

4

3

FIFOOvfl

CRCErr

set when the microprocessor or MFRC531 internal state machine

(e.g. receiver) tries to write data to the FIFO buffer when it is full

1

0

set when RxCRCEn is set and the CRC fails

automatically set during the PrepareRx state in the receiver start

phase

2

1

0

FramingErr

ParityErr

CollErr

1

0

set when the SOF is incorrect

automatically set during the PrepareRx state in the receiver start

phase

1

0

set when the parity check fails

automatically set during the PrepareRx state in the receiver start

phase

set when a bit-collision is detected^[1]

1

0

automatically set during the PrepareRx state in the receiver start

phase^[1]

[1] Only valid for communication using ISO/IEC 14443 A.

10.5.2.4 CollPos register

Bit position of the first bit-collision detected on the RF interface.

Table 59. CollPos register (address: 0Bh) reset value: 0000 0000b, 00h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

CollPos[7:0]

R

Table 60. CollPos register bit descriptions

Bit Symbol Description

7 to 0 CollPos[7:0] this register shows the bit position of the first detected collision in a

received frame.

Example:

00h indicates a bit collision in the start bit

01h indicates a bit collision in the 1^stbit

...

08h indicates a bit collision in the 8^thbit

Remark: A bit collision is not indicated in the CollPos register when using the

ISO/IEC 14443 B protocol standard.

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10.5.2.5 TimerValue register

Value of the timer.

Table 61. TimerValue register (address: 0Ch) reset value: xxxx xxxxb, xxh bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

TimerValue[7:0]

R

Table 62. TimerValue register bit descriptions

Bit

Symbol

Description

7 to 0

TimerValue[7:0] this register shows the timer counter value

10.5.2.6 CRCResultLSB register

LSB of the CRC coprocessor register.

Table 63. CRCResultLSB register (address: 0Dh) reset value: xxxx xxxxb, xxh bit

allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

CRCResultLSB[7:0]

R

Table 64. CRCResultLSB register bit descriptions

Bit Symbol Description

7 to 0 CRCResultLSB[7:0] gives the CRC register’s least significant byte value; only valid if

CRCReady = logic 1

10.5.2.7 CRCResultMSB register

MSB of the CRC coprocessor register.

Table 65. CRCResultMSB register (address: 0Eh) reset value: xxxx xxxxb, xxh bit

allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

CRCResultMSB[7:0]

R

Table 66. CRCResultMSB register bit descriptions

Bit

Symbol

Description

7 to 0

CRCResultMSB[7:0] gives the CRC register’s most significant byte value; only valid if

CRCReady = logic 1.

The register’s value is undefined for 8-bit CRC calculation.

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10.5.2.8 BitFraming register

Adjustments for bit oriented frames.

Table 67. BitFraming register (address: 0Fh) reset value: 0000 0000b, 00h bit allocation

Bit

7

0

6

5

RxAlign[2:0]

D

4

3

0

2

1

0

Symbol

Access

TxLastBits[2:0]

D

R/W

Table 68. BitFraming register bit descriptions

Bit

Symbol

Value Description

7

0

-

reserved

6 to 4 RxAlign[2:0]

defines the bit position for the first bit received to be stored in

the FIFO buffer. Additional received bits are stored in the next

subsequent bit positions. After reception, RxAlign[2:0] is

automatically cleared. For example:

000

001

the LSB of the received bit is stored in bit position 0 and the

second received bit is stored in bit position 1

the LSB of the received bit is stored in bit position 1, the

second received bit is stored in bit position 2

...

111

the LSB of the received bit is stored in bit position 7, the

second received bit is stored in the next byte in bit position 0

3

0

-

reserved

2 to 0 TxLastBits[2:0]

defines the number of bits of the last byte that shall be

transmitted. 000 indicates that all bits of the last byte will be

transmitted. TxLastBits[2:0] is automatically cleared after

transmission.

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10.5.3 Page 2: Transmitter and control

10.5.3.1 Page register

Selects the page register; see Section 10.5.1.1 “Page register” on page 48.

10.5.3.2 TxControl register

Controls the logical behavior of the antenna pin TX1 and TX2.

Table 69. TxControl register (address: 11h) reset value: 0101 1000b, 58h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

0

ModulatorSource

[1:0]

Force

100ASK

TX2Inv TX2Cw TX2RFEn TX1RFEn

Access

R/W

R/W R/W R/W R/W

Table 70. TxControl register bit descriptions

Bit

7

Symbol

Value Description

0

-

this value must not be changed

6 to 5

ModulatorSource[1:0]

selects the source for the modulator input:

modulator input is LOW

00

01

10

11

-

modulator input is HIGH

modulator input is the internal encoder

modulator input is pin MFIN

4

3

2

Force100ASK

TX2Inv

forces a 100 % ASK modulation independent

ModConductance register setting

0

1

delivers an inverted 13.56 MHz energy carrier output

signal on pin TX2

TX2Cw

delivers a continuously unmodulated 13.56 MHz

energy carrier output signal on pin TX2

0

1

enables modulation of the 13.56 MHz energy carrier

1

0

TX2RFEn

TX1RFEn

the output signal on pin TX2 is the 13.56 MHz energy

carrier modulated by the transmission data

0

1

TX2 is driven at a constant output level

the output signal on pin TX1 is the 13.56 MHz energy

carrier modulated by the transmission data

0

TX1 is driven at a constant output level

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10.5.3.3 CwConductance register

Selects the conductance of the antenna driver pins TX1 and TX2.

Table 71. CwConductance register (address: 12h) reset value: 0011 1111b, 3Fh bit

allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

00

GsCfgCW[5:0]

R/W

Table 72. CwConductance register bit descriptions

Bit

Symbol

Description

these values must not be changed

7 to 6

5 to 0

00

GsCfgCW[5:0] defines the conductance register value for the output driver. This

can be used to regulate the output power/current consumption and

operating distance.

See Section 9.9.3 on page 30 for detailed information about GsCfgCW[5:0].

10.5.3.4 ModConductance register

Defines the driver output conductance.

Table 73. ModConductance register (address: 13h) reset value: 0011 1111b, 3Fh bit

allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

00

GsCfgMod[5:0]

R/W

Table 74. ModConductance register bit descriptions

Bit

Symbol

00

Description

these values must not be changed

7 to 6

5 to 0

GsCfgMod[5:0]

defines the ModConductance register value for the output

driver during modulation. This is used to regulate the

modulation index.

Remark: When Force100ASK = logic 1, the GsCfgMod[5:0] value has no effect.

See Section 9.9.3 on page 30 for detailed information about GsCfgMod[5:0].

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10.5.3.5 CoderControl register

Sets the clock rate and the coding mode.

Table 75. CoderControl register (address: 14h) reset value: 0001 1001b, 19h bit allocation

Bit

7

6

5

4

CoderRate[2:0]

R/W

3

2

1

0

Symbol

Access

00

TxCoding[2:0]

R/W

Table 76. CoderControl register bit descriptions

Bit

Symbol

Value

Description

these values must not be changed

7 to 6 00

-

5 to 3 CoderRate[2:0]

this register defines the clock rate for the encoder circuit

MIFARE 848 kBd

000

001

010

011

100

111

MIFARE 424 kBd

MIFARE 212 kBd

MIFARE 106 kBd; ISO/IEC 14443 A

ISO/IEC 14443 B

reserved

2 to 0 TxCoding[2:0]

this register defines the bit encoding mode and framing during

transmission

000

001

010

011

NRZ according to ISO/IEC 14443 B

MIFARE, ISO/IEC 14443 A, (Miller coded)

reserved

10.5.3.6 ModWidth register

Selects the pulse modulation width.

Table 77. ModWidth register (address: 15h) reset value: 0001 0011b, 13h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

ModWidth[7:0]

R/W

Table 78. ModWidth register bit descriptions

Bit

Symbol

Description

7 to 0

ModWidth[7:0]

defines the width of the modulation pulse based on

t_mod= 2(ModWidth + 1) / f_clk

10.5.3.7 PreSet16 register

Table 79. PreSet16 register (address: 16h) reset value: 0000 0000b, 00h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

PreSet16[7:0]

R/W

Remark: These values must not be changed.

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10.5.3.8 TypeBFraming

Defines the framing for ISO/IEC 14443 B communication.

Table 80. TypeBFraming register (address: 17h) reset value: 0011 1011b, 3Bh bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

NoTxSOF NoTxEOF EOFWidth

R/W R/W R/W

CharSpacing[2:0]

R/W

SOFWidth[1:0]

R/W

Table 81. TypeBFraming register bit descriptions

Bit

Symbol

Value Description

7

NoTxSOF

1

0

1

0

1

0

TxCoder suppresses the SOF

TxCoder does not suppress SOF

TxCoder suppresses the EOF

6

5

NoTxEOF

EOFWidth

TxCoder does not suppress the EOF

set the EOF to a length to 11 ETU

set the EOF to a length of 10 ETU

set the EGT length between 0 and 7 ETU

4 to 2 CharSpacing[2:0]

1 to 0 SOFWidth[1:0]

00

01

10

11

sets the SOF to a length to 10 ETU LOW and 2 ETU HIGH

sets the SOF to a length of 10 ETU LOW and 3 ETU HIGH

sets the SOF to a length of 11 ETU LOW and 2 ETU HIGH

sets the SOF to a length of 11 ETU LOW and 3 ETU HIGH

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10.5.4 Page 3: Receiver and decoder control

10.5.4.1 Page register

Selects the page register; see Section 10.5.1.1 “Page register” on page 48.

10.5.4.2 RxControl1 register

Controls receiver operation.

Table 82. RxControl1 register (address: 19h) reset value: 0111 0011b, 73h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

SubCPulses[2:0]

R/W

ISOSelection[1:0]

R/W

LPOff

R/W

Gain[1:0]

R/W

Table 83. RxControl1 register bit descriptions

Bit

Symbol

Value Description

7 to 5

defines the number of subcarrier pulses for each bit

1 pulse for each bit

SubCPulses[2:0]

000

001

010

011

2 pulses for each bit

4 pulses for each bit

8 pulses for each bit ISO/IEC 14443 A and

ISO/IEC 14443 B

101

110

111

reserved

4 to 3 ISOSelection[1:0]

used to select the communication protocol

reserved

00

10

11

ISO/IEC 14443 A and ISO/IEC 14443 B

reserved

2

LPOff

switches off a low-pass filter at the internal amplifier

defines the receiver’s signal voltage gain factor

20 dB gain factor

1 to 0 Gain[1:0]

00

01

10

11

24 dB gain factor

31 dB gain factor

35 dB gain factor

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10.5.4.3 DecoderControl register

Controls decoder operation.

Table 84. DecoderControl register (address: 1Ah) reset value: 0000 1000b, 08h bit

allocation

Bit

7

0

6

5

4

3

2

1

0

Symbol

Access

RxMultiple ZeroAfterColl RxFraming[1:0]

R/W R/W R/W

00

RxCoding

R/W

Table 85. DecoderControl register bit descriptions

Bit

7

Symbol

0

Value Description

-

this value must not be changed

6

RxMultiple

0

1

after receiving one frame, the receiver is deactivated

enables reception of more than one frame

5

ZeroAfterColl

any bits received after a bit-collision are masked to zero. This

helps to resolve the anti-collision procedure as defined in

ISO/IEC 14443 A

4 to 3 RxFraming[1:0] 01

MIFARE or ISO/IEC 14443 A

this value must not be changed

Manchester encoding

2 to 1 00

-

0

RxCoding

0

1

BPSK encoding

10.5.4.4 BitPhase register

Selects the bit-phase between transmitter and receiver clock.

Table 86. BitPhase register (address: 1Bh) reset value: 1010 1101b, ADh bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

BitPhase[7:0]

R/W

Table 87. BitPhase register bit descriptions

Bit

Symbol

Description

7 to 0

BitPhase

defines the phase relationship between transmitter and receiver clock

Remark: The correct value of this register is essential for proper

operation.

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10.5.4.5 RxThreshold register

Selects thresholds for the bit decoder.

Table 88. RxThreshold register (address: 1Ch) reset value: 1111 1111b, FFh bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

MinLevel[3:0]

R/W

CollLevel[3:0]

R/W

Table 89. RxThreshold register bit descriptions

Bit

Symbol

Description

7 to 4

MinLevel[3:0]

the minimum signal strength the decoder will accept. If the signal

strength is below this level, it is not evaluated.

3 to 0

CollLevel[3:0]

the minimum signal strength the decoder input that must be reached

by the weaker half-bit of the Manchester encoded signal to generate

a bit-collision (relative to the amplitude of the stronger half-bit)

10.5.4.6 BPSKDemControl

Controls BPSK demodulation.

Table 90. BPSKDemControl register (address: 1Dh) reset value: 0001 1110b, 1Eh bit

allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

NoRxSOF NoRxEGT NoRxEOF FilterAmpDet

R/W R/W R/W R/W

TauD[1:0]

R/W

TauB[1:0]

R/W

Table 91. BPSKDemControl register bit descriptions

Bit

Symbol

Value Description

7

NoRxSOF

1

0

1

0

1

0

a missing SOF in the received data stream is ignored and no

framing errors are indicated

a missing SOF in the received data stream generates framing

errors

6

5

4

NoRxEGT

NoRxEOF

FilterAmpDet

an EGT which is too short or too long in the received data stream

is ignored and no framing errors are indicated

an EGT which is too short or too long in the received data stream

will cause framing errors

a missing EOF in the received data stream is ignored and no

framing errors indicated

a missing EOF in the receiving data stream produces framing

errors

-

switches on a high-pass filter for amplitude detection

3 to 2 TauD[1:0]

changes the time constant of the internal PLL whilst receiving

data

1 to 0 TauB[1:0]

-

changes the time constant of the internal PLL during data bursts

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10.5.4.7 RxControl2 register

Controls decoder behavior and defines the input source for the receiver.

Table 92. RxControl2 register (address: 1Eh) reset value: 0100 0001b, 41h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

RcvClkSelI RxAutoPD

R/W R/W

0000

R/W

DecoderSource[1:0]

R/W

Table 93. RxControl2 register bit descriptions

Bit

Symbol

Value Description

7

RcvClkSelI

1

0

1

I-clock is used as the receiver clock^[1]

Q-clock is used as the receiver clock^[1]

6

RxAutoPD

receiver circuit is automatically switched on before

receiving and switched off afterwards. This can be used to

reduce current consumption.

0

-

receiver is always activated

these values must not be changed

selects the source for the decoder input

LOW

5 to 2 0000

1 to 0 DecoderSource[1:0]

00

01

10

internal demodulator

a subcarrier modulated Manchester encoded signal on

pin MFIN

11

a baseband Manchester encoded signal on pin MFIN

[1] I-clock and Q-clock are 90 phase-shifted from each other.

10.5.4.8 ClockQControl register

Controls clock generation for the 90 phase-shifted Q-clock.

Table 94. ClockQControl register (address: 1Fh) reset value: 000x xxxxb, xxh bit allocation

Bit

7

6

5

0

4

3

2

1

0

Symbol

Access

ClkQ180Deg ClkQCalib

R/W

ClkQDelay[4:0]

D

R

R/W

Table 95. ClockQControl register bit descriptions

Bit

Symbol

Value Description

7

ClkQ180Deg

1

0

Q-clock is phase-shifted more than 180 compared to the

I-clock

Q-clock is phase-shifted less than 180 compared to the

I-clock

6

ClkQCalib

Q-clock is automatically calibrated after the reset phase and

after data reception from the card

1

-

no calibration is performed automatically

this value must not be changed

5

0

4 to 0

ClkQDelay[4:0]

-

this register shows the number of delay elements used to

generate a 90 phase-shift of the I-clock to obtain the

Q-clock. It can be written directly by the microprocessor or

by the automatic calibration cycle.

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10.5.5 Page 4: RF Timing and channel redundancy

10.5.5.1 Page register

Selects the page register; see Section 10.5.1.1 “Page register” on page 48.

10.5.5.2 RxWait register

Selects the time interval after transmission, before the receiver starts.

Table 96. RxWait register (address: 21h) reset value: 0000 0101b, 06h bit allocation

Bit

7

6

5

4

3

RxWait[7:0]

R/W

2

1

0

Symbol

Access

Table 97. RxWait register bit descriptions

Bit

Symbol

Function

7 to 0

RxWait[7:0]

after data transmission, the activation of the receiver is delayed

for RxWait bit-clock cycles. During this frame guard time any

signal on pin RX is ignored.

10.5.5.3 ChannelRedundancy register

Selects kind and mode of checking the data integrity on the RF channel.

Table 98. ChannelRedundancy register (address: 22h) reset value: 0000 0011b, 03h bit

allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

00

R/W R/W

CRC3309

R/W

CRC8 RxCRCEn TxCRCEn ParityOdd ParityEn

R/W R/W R/W R/W R/W

Table 99. ChannelRedundancy bit descriptions

Bit Symbol Value Function

7 to 6 00

-

this value must not be changed

5

CRC3309

1

CRC calculation is performed using ISO/IEC 3309

(ISO/IEC 14443 B)

0

1

0

1

CRC calculation is performed using ISO/IEC 14443 A

an 8-bit CRC is calculated

4

3

CRC8

a 16-bit CRC is calculated

RxCRCEn

the last byte(s) of a received frame are interpreted as CRC bytes. If

the CRC is correct, the CRC bytes are not passed to the FIFO. If

the CRC bytes are incorrect, the CRCErr flag is set.

0

1

no CRC is expected

2

TxCRCEn

a CRC is calculated over the transmitted data and the CRC bytes

are appended to the data stream

0

no CRC is transmitted

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Table 99. ChannelRedundancy bit descriptions …continued

Bit

Symbol

Value Function

1

ParityOdd

1

0

1

odd parity is generated or expected^[1]

even parity is generated or expected

0

ParityEn

a parity bit is inserted in the transmitted data stream after each byte

and expected in the received data stream after each byte (MIFARE,

ISO/IEC 14443 A)

0

no parity bit is inserted or expected (ISO/IEC 14443 B)

[1] When used with ISO/IEC 14443 A, this bit must be set to logic 1.

10.5.5.4 CRCPresetLSB register

LSB of the preset value for the CRC register.

Table 100. CRCPresetLSB register (address: 23h) reset value: 0101 0011b, 63h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

CRCPresetLSB[7:0]

R/W

Table 101. CRCPresetLSB register bit descriptions

Bit

Symbol

Description

7 to 0

CRCPresetLSB[7:0] defines the start value for CRC calculation. This value is loaded

into the CRC at the beginning of transmission, reception and

the CalcCRC command (if CRC calculation is enabled).

10.5.5.5 CRCPresetMSB register

MSB of the preset value for the CRC register.

Table 102. CRCPresetMSB register (address: 24h) reset value: 0101 0011b, 63h bit

allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

CRCPresetMSB[7:0]

R/W

Table 103. CRCPresetMSB bit descriptions

Bit Symbol Description

7 to 0 CRCPresetMSB[7:0]

defines the starting value for CRC calculation. This value is

loaded into the CRC at the beginning of transmission, reception

and the CalcCRC command (if the CRC calculation is enabled)

Remark: This register is not relevant if CRC8 is set to logic 1.

10.5.5.6 PreSet25 register

Table 104. PreSet25 register (address: 25h) reset value: 0000 0000b, 00h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

0000000

RW

Remark: These values must not be changed.

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10.5.5.7 MFOUTSelect register

Selects the internal signal applied to pin MFOUT.

Table 105. MFOUTSelect register (address: 26h) reset value: 0000 0000b, 00h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

00000

R/W

MFOUTSelect[2:0]

R/W

Table 106. MFOUTSelect register bit descriptions

Bit

Symbol

Value

Description

7 to 3 00000

-

these values must not be changed

defines which signal is routed to pin MFOUT:

constant LOW

2 to 0 MFOUTSelect[2:0]

000

001

010

constant HIGH

modulation signal (envelope) from the internal

encoder, (Miller coded)

011

100

serial data stream, not Miller encoded

output signal of the energy carrier demodulator (card

modulation signal)^[1]

101

output signal of the subcarrier demodulator

(Manchester encoded card signal)^[1]

110

111

reserved

[1] Only valid for MIFARE and ISO/IEC 14443 A communication at 106 kBd.

10.5.5.8 PreSet27 register

Table 107. PreSet27 (address: 27h) reset value: xxxx xxxxb, xxh bit allocation

Bit

7

x

6

x

5

x

4

x

3

x

2

x

1

x

0

x

Symbol

Access

W

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10.5.6 Page 5: FIFO, timer and IRQ pin configuration

10.5.6.1 Page register

Selects the page register; see Section 10.5.1.1 “Page register” on page 48.

10.5.6.2 FIFOLevel register

Defines the levels for FIFO underflow and overflow warning.

Table 108. FIFOLevel register (address: 29h) reset value: 0000 1000b, 08h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

00

WaterLevel[5:0]

R/W

Table 109. FIFOLevel register bit descriptions

Bit Symbol Description

7 to 6 00 these values must not be changed

5 to 0 WaterLevel[5:0] defines, the warning level of a FIFO buffer overflow or underflow:

HiAlert is set to logic 1, if the remaining FIFO buffer space is equal to

or less than the WaterLevel[5:0] bits in the FIFO buffer.

LoAlert is set to logic 1, if equal to or less than the WaterLevel[5:0] bits

in the FIFO buffer.

10.5.6.3 TimerClock register

Selects the divider for the timer clock.

Table 110. TimerClock register (address: 2Ah) reset value: 0000 0111b, 07h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

00

TAutoRestart

RW

TPreScaler[4:0]

RW

Table 111. TimerClock register bit descriptions

Bit Symbol Value Function

7 to 6 00

-

these values must not be changed

5

TAutoRestart

1

the timer automatically restarts its countdown from the

TReloadValue[7:0] instead of counting down to zero

0

-

the timer decrements to zero and register InterruptIrq

TimerIRq bit is set to logic 1

4 to 0 TPreScaler[4:0]

defines the timer clock frequency (f_TimerClock). The

TPreScaler[4:0] can be adjusted from 0 to 21. The following

formula is used to calculate the TimerClock frequency

(f_TimerClock):

f

_TimerClock= 13.56 MHz / 2^TPreScaler[MHz]

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10.5.6.4 TimerControl register

Selects start and stop conditions for the timer.

Table 112. TimerControl register (address: 2Bh) reset value: 0000 0110b, 06h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

0000

R/W

TStopRxEnd TStopRxBegin TStartTxEnd TStartTxBegin

R/W R/W R/W R/W

Table 113. TimerControl register bit descriptions

Bit Symbol Value Description

7 to 4 0000

-

these values must not be changed

3

2

1

TStopRxEnd

1

0

1

0

1

the timer automatically stops when data reception ends

the timer is not influenced by this condition

TStopRxBegin

TStartTxEnd

the timer automatically stops when the first valid bit is received

the timer is not influenced by this condition

the timer automatically starts when data transmission ends. If

the timer is already running, the timer restarts by loading

TReloadValue[7:0] into the timer.

0

1

the timer is not influenced by this condition

0

TStartTxBegin

the timer automatically starts when the first bit is transmitted. If

the timer is already running, the timer restarts by loading

TReloadValue[7:0] into the timer.

0

the timer is not influenced by this condition

10.5.6.5 TimerReload register

Defines the preset value for the timer.

Table 114. TimerReload register (address: 2Ch) reset value: 0000 1010b, 0Ah bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

TReloadValue[7:0]

R/W

Table 115. TimerReload register bit descriptions

Bit Symbol Description

7 to 0 TReloadValue[7:0] on a start event, the timer loads the TReloadValue[7:0] value.

Changing this register only affects the timer on the next start event. If

TReloadValue[7:0] is set to logic 0 the timer cannot start.

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10.5.6.6 IRQPinConfig register

Configures the output stage for pin IRQ.

Table 116. IRQPinConfig register (address: 2Dh) reset value: 0000 0010b, 02h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

000000

R/W

IRQInv IRQPushPull

R/W R/W

Table 117. IRQPinConfig register bit descriptions

Bit

7 to 2

1

Symbol

000000

IRQInv

Value Description

-

these values must not be changed

inverts the signal on pin IRQ with respect to bit IRq

1

0

1

0

the signal on pin IRQ is not inverted and is the same as bit IRq

pin IRQ functions as a standard CMOS output pad

pin IRQ functions as an open-drain output pad

0

IRQPushPull

10.5.6.7 PreSet2E register

Table 118. PreSet2E register (address: 2Eh) reset value: xxxx xxxxb, xxh bit allocation

Bit

7

x

6

x

5

x

4

x

3

x

2

x

1

x

0

x

Symbol

Access

W

10.5.6.8 PreSet2F register

Table 119. PreSet2F register (address: 2Fh) reset value: xxxx xxxxb, xxh bit allocation

Bit

7

x

6

x

5

x

4

x

3

x

2

x

1

x

0

x

Symbol

Access

W

10.5.7 Page 6: reserved

10.5.7.1 Page register

Selects the page register; see Section 10.5.1.1 “Page register” on page 48.

10.5.7.2 Reserved registers 31h, 32h, 33h, 34h, 35h, 36h and 37h

Table 120. Reserved registers (address: 31h, 32h, 33h, 34h, 35h, 36h, 37h)

reset value: xxxx xxxxb, xxh bit allocation

Bit

7

x

6

x

5

x

4

x

3

x

2

x

1

x

0

x

Symbol

Access

R/W

Remark: These registers are reserved for future use.

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10.5.8 Page 7: Test control

10.5.8.1 Page register

Selects the page register; see Section 10.5.1.1 “Page register” on page 48.

10.5.8.2 Reserved register 39h

Table 121. Reserved register (address: 39h) reset value: xxxx xxxxb, xxh bit allocation

Bit

7

x

6

x

5

x

4

x

3

x

2

x

1

x

0

x

Symbol

Access

W

Remark: This register is reserved for future use.

10.5.8.3 TestAnaSelect register

Selects analog test signals.

Table 122. TestAnaSelect register (address: 3Ah) reset value: 0000 0000b, 00h bit allocation

Bit

7

6

5

4

3

2

1

0

Symbol

Access

0000

W

TestAnaOutSel[4:0]

W

Table 123. TestAnaSelect bit descriptions

Bit

Symbol

Value Description

7 to 4

3 to 0

0000

-

these values must not be changed

TestAnaOutSel[4:0]

selects the internal analog signal to be routed to pin

AUX. See Section 15.2.2 on page 103 for detailed

information. The settings are as follows:

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

VMID

Vbandgap

VRxFollI

VRxFollQ

VRxAmpI

VRxAmpQ

VCorrNI

VCorrNQ

VCorrDI

VCorrDQ

VEvalL

VEvalR

VTemp

reserved

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10.5.8.4 Reserved register 3Bh

Table 124. Reserved register (address: 3Bh) reset value: xxxx xxxxb, xxh bit allocation

Bit

7

x

6

x

5

x

4

x

3

x

2

x

1

x

0

x

Symbol

Access

W

Remark: This register is reserved for future use.

10.5.8.5 Reserved register 3Ch

Table 125. Reserved register (address: 3Ch) reset value: xxxx xxxxb, xxh bit allocation

Bit

7

x

6

x

5

x

4

x

3

x

2

x

1

x

0

x

Symbol

Access

W

Remark: This register is reserved for future use.

10.5.8.6 TestDigiSelect register

Selects digital test mode.

Table 126. TestDigiSelect register (address: 3Dh) reset value: xxxx xxxxb, xxh bit allocation

Bit

7

SignalToMFOUT

W

6

5

4

3

2

1

0

Symbol

Access

TestDigiSignalSel[6:0]

W

Table 127. TestDigiSelect register bit descriptions

Bit

Symbol

Value Description

7

SignalToMFOUT

1

overrules the MFOUTSelect[2:0] setting and routes the

digital test signal defined with the TestDigiSignalSel[6:0]

bits to pin MFOUT

0

-

MFOUTSelect[2:0] defines the signal on pin MFOUT

6 to 0 TestDigiSignalSel[6:0]

selects the digital test signal to be routed to pin MFOUT.

Refer to Section 15.2.3 on page 104 for detailed

information. The following lists the signal names for the

TestDigiSignalSel[6:0] addresses:

F4h

E4h

D4h

C4h

B5h

A5h

96h

83h

E2h

s_data

s_valid

s_coll

s_clock

rd_sync

wr_sync

int_clock

BPSK_out

BPSK_sig

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10.5.8.7 Reserved registers 3Eh, 3Fh

Table 128. Reserved register (address: 3Eh, 3Fh) reset value: xxxx xxxxb, xxh bit allocation

Bit

7

x

6

x

5

x

4

x

3

x

2

x

1

x

0

x

Symbol

Access

W

Remark: This register is reserved for future use.

11. MFRC531 command set

MFRC531 operation is determined by an internal state machine capable of performing a

command set. The commands can be started by writing the command code to the

Command register. Arguments and/or data necessary to process a command are mainly

exchanged using the FIFO buffer.

• Each command needing a data stream (or data byte stream) as an input immediately

processes the data in the FIFO buffer

• Each command that requires arguments only starts processing when it has received

the correct number of arguments from the FIFO buffer

• The FIFO buffer is not automatically cleared at the start of a command. It is, therefore,

possible to write command arguments and/or the data bytes into the FIFO buffer

before starting a command.

• Each command (except the StartUp command) can be interrupted by the

microprocessor writing a new command code to the Command register e.g. the Idle

command.

11.1 MFRC531 command overview

Table 129. MFRC531 commands overview

Command

Value Action

FIFO communication

Arguments and data

sent

Data received

StartUp

3Fh

runs the reset and initialization phase. See

-

Section 11.1.2 on page 75.

Remark: This command can only be activated by

Power-On or Hard resets.

Idle

00h

1Ah

16h

no action; cancels execution of the current command.

See Section 11.1.3 on page 75

-

Transmit

Receive

transmits data from the FIFO buffer to the card. See

Section 11.2.1 on page 76

data stream

-

activates receiver circuitry. Before the receiver starts,

the state machine waits until the time defined in the

RxWait register has elapsed. See Section 11.2.2 on

page 79.

data stream

Remark: This command may be used for test

purposes only, since there is no timing relationship to

the Transmit command.

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Table 129. MFRC531 commands overview …continued

Command

Value Action

FIFO communication

Arguments and data

sent

Data received

Transceive^[1]1Eh

transmits data from FIFO buffer to the card and

automatically activates the receiver after

data stream

transmission. The receiver waits until the time defined

in the RxWait register has elapsed before starting.

See Section 11.2.3 on page 82.

WriteE2

ReadE2

01h

03h

reads data from the FIFO buffer and writes it to the

EEPROM. See Section 11.3.1 on page 84.

start address LSB

start address MSB

data byte stream

-

reads data from the EEPROM and sends it to the

FIFO buffer. See Section 11.3.2 on page 86.

start address LSB

start address MSB

number of data bytes

data bytes

Remark: Keys cannot be read back

LoadKeyE2 0Bh

copies a key from the EEPROM into the key buffer^[2]start address LSB

See Section 11.6.1 on page 88.

-

start address MSB

LoadKey

Authent1

19h

reads a key from the FIFO buffer and loads it into the byte 0 LSB

key buffer^[2]. See Section 11.6.2 on page 88.

byte 1

Remark: The key has to be prepared in a specific

format (refer to Section 9.2.3.1 “Key format” on page

…

byte 10

16)

byte 11 MSB

0Ch

performs the first part of card authentication using the card Authent1 command -

Crypto1 algorithm^[2]. See Section 11.6.3 on page 89.

card block address

card serial number

LSB

card serial number

byte 1

card serial number

byte 2

card serial number

MSB

Authent2

14h

performs the second part of card authentication using

the Crypto1 algorithm^[2]. See Section 11.6.4 on

page 89.

-

LoadConfig

CalcCRC

07h

12h

reads data from EEPROM and initializes the

MFRC531 registers. See Section 11.4.1 on page 86.

start address LSB

start address MSB

data byte stream

-

activates the CRC coprocessor

Remark: The result of the CRC calculation is read

from the CRCResultLSB and CRCResultMSB

registers. See Section 11.4.2 on page 87.

[1] This command is the combination of the Transmit and Receive commands.

[2] Relates to MIFARE Mini/MIFARE 1K/MIFARE 4K security.

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11.1.1 Basic states

11.1.2 StartUp command 3Fh

Table 130. StartUp command 3Fh

Command

Value Action

Arguments

and data

Returned

data

StartUp

3Fh runs the reset and initialization phase

-

Remark: This command can only be activated by a Power-On or Hard reset.

The StartUp command runs the reset and initialization phases. It does not need or return,

any data. It cannot be activated by the microprocessor but is automatically started after

one of the following events:

• Power-On Reset (POR) caused by power-up on pin DVDD

• POR caused by power-up on pin AVDD

• Negative edge on pin RSTPD

The reset phase comprises an asynchronous reset and configuration of certain register

bits. The initialization phase configures several registers with values stored in the

EEPROM.

When the StartUp command finishes, the Idle command is automatically executed.

Remark:

• The microprocessor must not write to the MFRC531 while it is still executing the

StartUp command. To avoid this, the microprocessor polls for the Idle command to

determine when the initialization phase has finished; see Section 9.7.4 on page 28.

• When the StartUp command is active, it is only possible to read from the Page 0

register.

• The StartUp command cannot be interrupted by the microprocessor.

11.1.3 Idle command 00h

Table 131. Idle command 00h

Command

Value

Action

Arguments Returned

and data

data

Idle

00h

no action; cancels current command

execution

-

The Idle command switches the MFRC531 to its inactive state where it waits for the next

command. It does not need or return, any data.

The device automatically enters the idle state when a command finishes. When this

happens, the MFRC531 sends an interrupt request by setting bit IdleIRq. When triggered

by the microprocessor, the Idle command can be used to stop execution of all other

commands (except the StartUp command) but this does not generate an interrupt request

(IdleIRq).

Remark: Stopping command execution with the Idle command does not clear the FIFO

buffer.

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11.2 Commands for ISO/IEC 14443 A card communication

The MFRC531 is a fully ISO/IEC 14443 A and ISO/IEC 14443 B compliant reader IC. This

enables the command set to be more flexible and generalized when compared to

dedicated MIFARE reader ICs. Section 11.2.1 to Section 11.2.5 describe the command

set for ISO/IEC 14443 A card communication and related communication protocols.

11.2.1 Transmit command 1Ah

Table 132. Transmit command 1Ah

Command Value

Action

Arguments Returned

and data

data

Transmit 1Ah

transmits data from FIFO buffer to card

data stream

-

The Transmit command reads data from the FIFO buffer and sends it to the transmitter. It

does not return any data. The Transmit command can only be started by the

microprocessor.

11.2.1.1 Using the Transmit command

To transmit data, one of the following sequences can be used:

1. All data to be transmitted to the card is written to the FIFO buffer while the Idle

command is active. Then the command code for the Transmit command is written to

the Command register.

Remark: This is possible for transmission of a data stream up to 64 bytes.

2. The command code for the Transmit command is stored in the Command register.

Since there is not any data available in the FIFO buffer, the command is only enabled

but transmission is not activated. Data transmission starts when the first data byte is

written to the FIFO buffer. To generate a continuous data stream on the RF interface,

the microprocessor must write the subsequent data bytes into the FIFO buffer in time.

Remark: This allows transmission of any data stream length but it requires data to be

written to the FIFO buffer in time.

3. Part of the data transmitted to the card is written to the FIFO buffer while the Idle

command is active. Then the command code for the Transmit command is written to

the Command register. While the Transmit command is active, the microprocessor

can send further data to the FIFO buffer. This is then appended by the transmitter to

the transmitted data stream.

Remark: This allows transmission of any data stream length but it requires data to be

written to the FIFO buffer in time.

When the transmitter requests the next data byte to ensure the data stream on the RF

interface is continuous and the FIFO buffer is empty, the Transmit command automatically

terminates. This causes the internal state machine to change its state from transmit to

idle.

When the data transmission to the card is finished, the TxIRq flag is set by the MFRC531

to indicate to the microprocessor transmission is complete.

Remark: If the microprocessor overwrites the transmit code in the Command register

with another command, transmission stops immediately on the next clock cycle. This can

produce output signals that are not in accordance with ISO/IEC 14443 A.

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11.2.1.2 RF channel redundancy and framing

Each ISO/IEC 14443 A transmitted frame consists of a Start Of Frame (SOF) pattern,

followed by the data stream and is closed by an End Of Frame (EOF) pattern. These

different phases of the transmission sequence can be monitored using the PrimaryStatus

register ModemState[2:0] bit; see Section 11.2.4 on page 82.

Depending on the setting of the ChannelRedundancy register bit TxCRCEn, the CRC is

calculated and appended to the data stream. The CRC is calculated according to the

settings in the ChannelRedundancy register. Parity generation is handled according to the

ChannelRedundancy register ParityEn and ParityOdd bits settings.

11.2.1.3 Transmission of bit oriented frames

The transmitter can be configured to send an incomplete last byte. To achieve this the

BitFraming register’s TxLastBits[2:0] bits must be set at above zero (for example, 1). This

is shown in Figure 15.

TxLastBits = 0

TxLastBits = 7

TxLastBits = 1

SOF

0

7

P

0

7

P

EOF

6

EOF

001aak618

Fig 15. Transmitting bit oriented frames

Figure 15 shows the data stream if bit ParityEn is set in the ChannelRedundancy register.

All fully transmitted bytes are followed by a parity check bit but the incomplete byte is not

followed by a parity check bit. After transmission, the TxLastBits[2:0] bits are automatically

cleared.

Remark: If the TxLastBits[2:0] bits are not equal to zero, CRC generation must be

disabled. This is done by clearing the ChannelRedundancy register TxCRCEn bit.

11.2.1.4 Transmission of frames with more than 64 bytes

To generate frames of more than 64 bytes, the microprocessor must write data to the

FIFO buffer while the Transmit command is active. The state machine checks the FIFO

buffer status when it starts transmitting the last bit of the data stream; the check time is

marked in Figure 16 with arrows.

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TxLastBits[2:0]

FIFOLength[6:0]

FIFO empty

TxLastBits = 0

01h

00h

TxData

check FIFO empty

accept further data

7

0

7

0

7

001aak619

Fig 16. Timing for transmitting byte oriented frames

As long as the internal accept further data signal is logic 1, further data can be written to

the FIFO buffer. The MFRC531 appends this data to the data stream transmitted using the

RF interface.

If the internal accept further data signal is logic 0, the transmission terminates. All data

written to the FIFO buffer after accept further data signal was set to logic 0 is not

transmitted, however, it remains in the FIFO buffer.

Remark: If parity generation is enabled (ParityEn = logic 1), the parity bit is the last bit

transmitted. This delays the accept further data signal by a duration of one bit.

If the TxLastBits[2:0] bits are not zero, the last byte is not transmitted completely. Only the

number of bits set by TxLastBits[2:0], starting with the least significant bit are transmitted.

This means that the internal state machine has to check the FIFO buffer status at an

earlier point in time; see Figure 17.

NWR (FIFO data)

TxLastBits[2:0]

FIFOLength[6:0]

FIFO empty

TxLastBits = 4

01h

00h

TxData

check FIFO empty

accept further data

4

7

0

3

4

7

0

3

001aak620

Fig 17. Timing for transmitting bit oriented frames

Since in this example TxLastBits[2:0] = 4, transmission stops after bit 3 is transmitted and

the frame is completed with an EOF, if configured.

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Figure 17 also shows write access to the FIFOData register just before the FIFO buffer’s

status is checked. This leads to FIFO empty state being held LOW which keeps the

accept further data active. The new byte written to the FIFO buffer is transmitted using the

RF interface.

Accept further data is only changed by the check FIFO empty function. This function

verifies FIFO empty for one bit duration before the last expected bit transmission.

Table 133. Transmission of frames of more than 64 bytes

Frame definition

8-bit with parity

Verification at:

8

^thbit

8-bit without parity

x-bit without parity

7

(x  1)^thbit

11.2.2 Receive command 16h

Table 134. Receive command 16h

Command

Value

Action

Arguments Returned

and data

data

Receive

16h

activates receiver circuitry

-

data stream

The Receive command activates the receiver circuitry. All data received from the RF

interface is written to the FIFO buffer. The Receive command can be started either using

the microprocessor or automatically during execution of the Transceive command.

Remark: This command can only be used for test purposes since there is no timing

relationship to the Transmit command.

11.2.2.1 Using the Receive command

After starting the Receive command, the internal state machine decrements to the RxWait

register value on every bit-clock. The analog receiver circuitry is prepared and activated

from 3 down to 1. When the counter reaches 0, the receiver starts monitoring the incoming

signal at the RF interface.

When the signal strength reaches a level higher than the RxThreshold register

MinLevel[3:0] bits value, it starts decoding. The decoder stops when the signal can no

longer be detected on the receiver input pin RX. The decoder sets bit RxIRq indicating

receive termination.

The different phases of the receive sequence are monitored using the PrimaryStatus

register ModemState[2:0] bits; see Section 11.2.4 on page 82.

Remark: Since the counter values from 3 to 0 are needed to initialize the analog receiver

circuitry, the minimum value for RxWait[7:0] is 3.

11.2.2.2 RF channel redundancy and framing

The decoder expects the SOF pattern at the beginning of each data stream. When the

SOF is detected, it activates the serial-to-parallel converter and gathers the incoming data

bits. Every completed byte is forwarded to the FIFO buffer.

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If an EOF pattern is detected or the signal strength falls below the RxThreshold register

MinLevel[3:0] bits setting, both the receiver and the decoder stop. Then the Idle command

is entered and an appropriate response for the microprocessor is generated (interrupt

request activated, status flags set).

When the ChannelRedundancy register bit RxCRCEn is set, a CRC block is expected.

The CRC block can be one byte or two bytes depending on the ChannelRedundancy

register CRC8 bit setting.

Remark: If the CRC block received is correct, it is not sent to the FIFO buffer. This is

realized by shifting the incoming data bytes through an internal buffer of either one or two

bytes (depending on the defined CRC). The CRC block remains in this internal buffer.

Consequently, all data bytes in the FIFO buffer are delayed by one or two bytes. If the

CRC fails, all received bytes are sent to the FIFO buffer including the faulty CRC.

If ParityEn is set in the ChannelRedundancy register, a parity bit is expected after each

byte. If ParityOdd = logic 1, the expected parity is odd, otherwise even parity is expected.

11.2.2.3 Collision detection

If more than one card is within the RF field during the card selection phase, they both

respond simultaneously. The MFRC531 supports the algorithm defined in

ISO/IEC 14443 A to resolve card serial number data collisions by performing the

anti-collision procedure. The basis for this procedure is the ability to detect bit-collisions.

Bit-collision detection is supported by the Manchester coding bit encoding scheme used in

the MFRC531. If in the first and second half-bit of a subcarrier, modulation is detected,

instead of forwarding a 1-bit or 0-bit, a bit-collision is indicated. The MFRC531 uses the

RxThreshold register CollLevel[3:0] bits setting to distinguish between a 1-bit or 0-bit and

a bit-collision. If the amplitude of the half-bit with smaller amplitude is larger than that

defined by the CollLevel[3:0] bits, the MFRC531 flags a bit-collision using the error flag

CollErr. If a bit-collision is detected in a parity bit, the ParityErr flag is set.

On a detected collision, the receiver continues receiving the incoming data stream. In the

case of a bit-collision, the decoder sends logic 1 at the collision position.

Remark: As an exception, if bit ZeroAfterColl is set, all bits received after the first

bit-collision are forced to zero, regardless whether a bit-collision or an unequivocal state

has been detected. This feature makes it easier for the control software to perform the

anti-collision procedure as defined in ISO/IEC 14443 A.

When the first bit collision in a frame is detected, the bit-collision position is stored in the

CollPos register.

Table 135 shows the collision positions.

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Table 135. Return values for bit-collision positions

Collision in bit

CollPos register value

(Decimal)

SOF

0

Least Significant Bit (LSB) of the Least Significant Byte (LSByte)

1

…

8

Most Significant Bit (MSB) of the LSByte

LSB of second byte

9

…

16

17

…

MSB of second byte

LSB of third byte

…

Parity bits are not counted in the CollPos register because bit-collisions in parity bit occur

after bit-collisions in the data bits. If a collision is detected in the SOF, a frame error is

flagged and no data is sent to the FIFO buffer. In this case, the receiver continues to

monitor the incoming signal. It generates the correct notifications to the microprocessor

when the end of the faulty input stream is detected. This helps the microprocessor to

determine when it is next allowed to send data to the card.

11.2.2.4 Receiving bit oriented frames

The receiver can manage byte streams with incomplete bytes which result in bit-oriented

frames. To support this, the following values may be used:

• BitFraming register’s RxAlign[2:0] bits select a bit offset for the first incoming byte. For

example, if RxAlign[2:0] = 3, the first 5 bits received are forwarded to the FIFO buffer.

Further bits are packed into bytes and forwarded. After reception, RxAlign[2:0] is

automatically cleared. If RxAlign[2:0] = logic 0, all incoming bits are packed into one

byte.

• RxLastBits[2:0] returns the number of bits valid in the last received byte. For example,

if RxLastBits[2:0] evaluates to 5 bits at the end of the received command, the 5 least

significant bits are valid. If the last byte is complete, RxLastBits[2:0] evaluates to zero.

RxLastBits[2:0] is only valid if a frame error is not indicated by the FramingErr flag. If

RxAlign[2:0] is not zero and ParityEn is active, the first parity bit is ignored and not

checked.

11.2.2.5 Communication errors

The events which can set error flags are shown in Table 136.

Table 136. Communication error table

Cause

Flag bit

FramingErr

CRCErr

ParityErr

CollErr

Received data did not start with the SOF pattern

CRC block is not equal to the expected value

Received data is shorter than the CRC block

The parity bit is not equal to the expected value (i.e. a bit-collision, not parity)

A bit-collision is detected

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11.2.3 Transceive command 1Eh

Table 137. Transceive command 1Eh

Command Value

Action

Arguments Returned

and data

data

Transceive 1Eh

transmits data from FIFO buffer to the card data stream data stream

and then automatically activates the

receiver

The Transceive command first executes the Transmit command (see Section 11.2.1 on

page 76) and then starts the Receive command (see Section 11.2.2 on page 79). All data

transmitted is sent using the FIFO buffer and all data received is written to the FIFO buffer.

The Transceive command can only be started by the microprocessor.

Remark: To adjust the timing relationship between transmitting and receiving, use the

RxWait register. This register is used to define the time delay between the last bit

transmitted and activation of the receiver. In addition, the BitPhase register determines the

phase-shift between the transmitter and receiver clock.

11.2.4 States of the card communication

The status of the transmitter and receiver state machine can be read from bits

ModemState[2:0] in the PrimaryStatus register.

The assignment of ModemState[2:0] to the internal action is shown in Table 138.

Table 138. Meaning of ModemState

ModemState State

[2:0]

Description

000

001

010

Idle

transmitter and/or receiver are not operating

transmitting the SOF pattern

TxSOF

TxData

transmitting data from the FIFO buffer (or redundancy CRC check

bits)

011

100

TxEOF

transmitting the EOF pattern

GoToRx1

GoToRx2

PrepareRx

AwaitingRx

intermediate state passed, when receiver starts

intermediate state passed, when receiver finishes

waiting until the RxWait register time period expires

receiver activated; waiting for an input signal on pin RX

101

110

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11.2.5 Card communication state diagram

COMMAND =

TRANSMIT,

RECEIVE OR

TRANSCEIVE

IDLE

(000)

FIFO not empty

and command =

command = Receive

Transmit or Transceive

TxSOF

GoToRx1

(001)

(100)

SOF transmitted

next bit clock

TxData

(010)

Prepare Rx

(101)

EOF transmitted and

command = Transceive

data transmitted

RxWaitC[7:0] = 0

TxEOF

(011)

Awaiting Rx

(110)

RxMultiple = 1

signal strength > MinLevel[3:0]

EOF transmitted and

command = Transmit

RECEIVING

(111)

frame received

end of receive frame

and

RxMultiple = 0

GoToRx2

(100)

SET

COMMAND REGISTER = IDLE

(000)

001aak621

Fig 18. Card communication state diagram

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11.3 EEPROM commands

11.3.1 WriteE2 command 01h

Table 139. WriteE2 command 01h

Command Value Action

FIFO

Arguments and

data

Returned

data

WriteE2

01h

get data from FIFO buffer and write it start address LSB

-

to the EEPROM

start address MSB

data byte stream

The WriteE2 command interprets the first two bytes in the FIFO buffer as the EEPROM

start byte address. Any further bytes are interpreted as data bytes and are programmed

into the EEPROM, starting from the given EEPROM start byte address. This command

does not return any data.

The WriteE2 command can only be started by the microprocessor. It will not stop

automatically but has to be stopped explicitly by the microprocessor by issuing the Idle

command.

11.3.1.1 Programming process

Up to 16 bytes can be programmed into the EEPROM during a single programming cycle.

The time needed is approximately 5.8 ms.

The state machine copies all the prepared data bytes to the FIFO buffer and then to the

EEPROM input buffer. The internal EEPROM input buffer is 16 bytes long which is equal

to the block size of the EEPROM. A programming cycle is started if the last position of the

EEPROM input buffer is written or if the last byte of the FIFO buffer has been read.

The E2Ready flag remains logic 0 when there are unprocessed bytes in the FIFO buffer or

the EEPROM programming cycle is still in progress. When all the data from the FIFO

buffer are programmed into the EEPROM, the E2Ready flag is set to logic 1. Together

with the rising edge of E2Ready, the TxIRq interrupt request flag shows logic 1. This can

be used to generate an interrupt when programming of all data is finished.

Remark: During the E2PROM programming indicated by E2Ready = logic 0, the WriteE2

command cannot be stopped using any other command.

Once E2Ready = logic 1, the WriteE2 command can be stopped by the microprocessor by

sending the Idle command.

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11.3.1.2 Timing diagram

Figure 19 shows programming five bytes into the EEPROM.

t

prog,del

NWR

data

write addr addr

E2 LSB MSB

Idle

command

byte 0 byte 1

byte 2

byte 3

byte 4

WriteE2

command active

t

prog

EEPROM

programming

byte 1, byte 2 and byte 3

programming byte 0

programming byte 4

E2Ready

TxIRq

001aak623

Fig 19. EEPROM programming timing diagram

Assuming that the MFRC531 finds and reads byte 0 before the microprocessor is able to

write byte 1 (t_prog,del= 300 ns). This causes the MFRC531 to start the programming cycle

(t_prog), which takes approximately 5.8 ms to complete. In the meantime, the

microprocessor stores byte 1 to byte 4 in the FIFO buffer.

If the EEPROM start byte address is 16Ch then byte 0 is stored at that address. The

MFRC531 copies the subsequent data bytes into the EEPROM input buffer. Whilst

copying byte 3, it detects that this data byte has to be programmed at the EEPROM byte

address 16Fh. As this is the end of the memory block, the MFRC531 automatically starts

a programming cycle.

Next, byte 4 is programmed at the EEPROM byte address 170h. As this is the last data

byte, the E2Ready and TxIRq flags are set indicating the end of the EEPROM

programming activity.

Although all data has been programmed into the E2PROM, the MFRC531 stays in the

WriteE2 command. Writing more data to the FIFO buffer would lead to another EEPROM

programming cycle continuing from EEPROM byte address 171h. The command is

stopped using the Idle command.

11.3.1.3 WriteE2 command error flags

Programming is restricted for EEPROM block 0 (EEPROM byte address 00h to 0Fh). If

you program these addresses, the AccessErr flag is set and a programming cycle is not

started.

Addresses above 1FFh are taken modulo 200h; see Section 9.2 on page 12 for the

EEPROM memory organization.

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11.3.2 ReadE2 command 03h

Table 140. ReadE2 command 03h

Command Value Action

Arguments

Returned data

ReadE2

03h

reads EEPROM data and

stores it in the FIFO buffer

start address LSB

start address MSB

number of data bytes

data bytes

The ReadE2 command interprets the first two bytes stored in the FIFO buffer as the

EEPROM starting byte address. The next byte specifies the number of data bytes

returned.

When all three argument bytes are available in the FIFO buffer, the specified number of

data bytes are copied from the EEPROM into the FIFO buffer, starting from the given

EEPROM starting byte address.

The ReadE2 command can only be triggered by the microprocessor and it automatically

stops when all data has been copied.

11.3.2.1 ReadE2 command error flags

Reading is restricted to EEPROM blocks 8h to 1Fh (key memory area). Reading from

these addresses sets the flag AccessErr = logic 1.

Addresses above 1FFh are taken as modulo 200h; see Section 9.2 on page 12 for the

EEPROM memory organization.

11.4 Diverse commands

11.4.1 LoadConfig command 07h

Table 141. LoadConfig command 07h

Command

Value Action

Arguments and

data

Returned data

LoadConfig

07h

reads data from EEPROM and start address LSB

-

initializes the registers

start address MSB

The LoadConfig command interprets the first two bytes found in the FIFO buffer as the

EEPROM starting byte address. When the two argument bytes are available in the FIFO

buffer, 32 bytes from the EEPROM are copied into the Control and other relevant

registers, starting at the EEPROM starting byte address. The LoadConfig command can

only be started by the microprocessor and it automatically stops when all relevant

registers have been copied.

11.4.1.1 Register assignment

The 32 bytes of EEPROM content are written to the MFRC531 registers 10h to register

2Fh; see Section 9.2 on page 12 for the EEPROM memory organization.

Remark: The procedure for the register assignment is the same as it is for the startup

initialization (see Section 9.7.3 on page 28). The difference is, the EEPROM starting byte

address for the StartUp initialization is fixed to 10h (block 1, byte 0). However, it can be

chosen with the LoadConfig command.

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11.4.1.2 Relevant LoadConfig command error flags

Valid EEPROM starting byte addresses are between 10h and 60h.

Copying from block 8h to 1Fh (keys) is restricted. Reading from these addresses sets the

flag AccessErr = logic 1.

Addresses above 1FFh are taken as modulo 200h; see Section 9.2 on page 12 for the

EEPROM memory organization.

11.4.2 CalcCRC command 12h

Table 142. CalcCRC command 12h

Command Value Action

Arguments and

data

Returned data

CalcCRC 12h activates the CRC coprocessor

data byte stream

-

The CalcCRC command takes all the data from the FIFO buffer as the input bytes for the

CRC coprocessor. All data stored in the FIFO buffer before the command is started is

processed.

This command does not return any data to the FIFO buffer but the content of the CRC can

be read using the CRCResultLSB and CRCResultMSB registers.

The CalcCRC command can only be started by the microprocessor and it does not

automatically stop. It must be stopped by the microprocessor sending the Idle command.

If the FIFO buffer is empty, the CalcCRC command waits for further input before

proceeding.

11.4.2.1 CRC coprocessor settings

Table 143 shows the parameters that can be configured for the CRC coprocessor.

Table 143. CRC coprocessor parameters

Parameter

Value

Bit

Register

CRC register

length

8-bit or 16-bit CRC

CRC8

ChannelRedundancy

CRC algorithm

ISO/IEC 14443 A or ISO/IEC 3309 CRC3309

ChannelRedundancy

CRC preset value any

CRCPresetLSB CRCPresetLSB

CRCPresetMSB CRCPresetMSB

The CRC polynomial for the 8-bit CRC is fixed to x⁸+ x⁴+ x³+ x²+ 1.

The CRC polynomial for the 16-bit CRC is fixed to x¹⁶+ x¹²+ x⁵+ 1.

11.4.2.2 CRC coprocessor status flags

The CRCReady status flag indicates that the CRC coprocessor has finished processing

all the data bytes in the FIFO buffer. When the CRCReady flag is set to logic 1, an

interrupt is requested which sets the TxIRq flag. This supports interrupt driven use of the

CRC coprocessor.

When CRCReady and TxIRq flags are set to logic 1 the content of the CRCResultLSB

and CRCResultMSB registers and the CRCErr flag are valid. The CRCResultLSB and

CRCResultMSB registers hold the content of the CRC, the CRCErr flag indicates CRC

validity for the processed data.

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11.5 Error handling during command execution

If an error is detected during command execution, the PrimaryStatus register Err flag is

set. The microprocessor can evaluate the status flags in the ErrorFlag register to get

information about the cause of the error.

Table 144. ErrorFlag register error flags overview

Error flag

KeyErr

Related commands

LoadKeyE2, LoadKey

WriteE2, ReadE2, LoadConfig

no specific commands

Receive, Transceive, CalcCRC

Receive, Transceive

AccessErr

FIFOOvlf

CRCErr

FramingErr

ParityErr

CollErr

Receive, Transceive

11.6 MIFARE security commands

11.6.1 LoadKeyE2 command 0Bh

Table 145. LoadKeyE2 command 0Bh

Command

Value Action

Arguments and

data

Returned

data

LoadKeyE2

0Bh

reads a key from the EEPROM and start address LSB

-

puts it into the internal key buffer

start address MSB

The LoadKeyE2 command interprets the first two bytes found in the FIFO buffer as the

EEPROM starting byte address. The EEPROM bytes starting from the given starting byte

address are interpreted as the key when stored in the correct key format as described in

Section 9.2.3.1 “Key format” on page 16. When both argument bytes are available in the

FIFO buffer, the command executes.

The LoadKeyE2 command can only be started by the microprocessor and it automatically

stops after copying the key from the EEPROM to the key buffer.

11.6.1.1 Relevant LoadKeyE2 command error flags

If the key format is incorrect (see Section 9.2.3.1 “Key format” on page 16) an undefined

value is copied into the key buffer and the KeyErr flag is set.

11.6.2 LoadKey command 19h

Table 146. LoadKey command 19h

Command Value Action

Arguments and Returned

data

LoadKey

19h

reads a key from the FIFO buffer and puts it byte 0 (LSB)

-

into the key buffer

byte 1

…

byte 10

byte 11 (MSB)

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The LoadKey command interprets the first twelve bytes it finds in the FIFO buffer as the

key when stored in the correct key format as described in Section 9.2.3.1 “Key format” on

page 16. When the twelve argument bytes are available in the FIFO buffer they are

checked and, if valid, are copied into the key buffer.

The LoadKey command can only be started by the microprocessor and it automatically

stops after copying the key from the FIFO buffer to the key buffer.

11.6.2.1 Relevant LoadKey command error flags

All bytes requested are copied from the FIFO buffer to the key buffer. If the key format is

not correct (see Section 9.2.3.1 “Key format” on page 16) an undefined value is copied

into the key buffer and the KeyErr flag is set.

11.6.3 Authent1 command 0Ch

Table 147. Authent1 command 0Ch

Command Value Action

Arguments and data

Returned

data

Authent1

0Ch

performs the first part of the Crypto1 card Authent1 command

-

card authentication

card block address

card serial number LSB

card serial number byte1

card serial number byte2

card serial number MSB

The Authent1 command is a special Transceive command; it sends six argument bytes to

the card. The card’s response is not sent to the microprocessor, it is used instead to

authenticate the card to the MFRC531 and vice versa.

The Authent1 command can be triggered only by the microprocessor. The sequence of

states for this command are the same as those for the Transceive command; see

Section 11.2.3 on page 82.

11.6.4 Authent2 command 14h

Table 148. Authent2 command 14h

Command Value Action

Arguments

and data

Returned

data

Authent2

14h

performs the second part of the card

-

authentication using the Crypto1 algorithm

The Authent2 command is a special Transceive command. It does not need any argument

byte, however all the data needed to be sent to the card is assembled by the MFRC531.

The card response is not sent to the microprocessor but is used to authenticate the card

to the MFRC531 and vice versa.

The Authent2 command can only be started by the microprocessor. The sequence of

states for this command are the same as those for the Transceive command; see

Section 11.2.3 on page 82.

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11.6.4.1 Authent2 command effects

If the Authent2 command is successful, the authenticity of card and the MFRC531 are

proved. This automatically sets the Crypto1On control bit. When bit Crypto1On = logic 1,

all further card communication is encrypted using the Crypto1 security algorithm. If the

Authent2 command fails, bit Crypto1On is cleared (Crypto1On = logic 0).

Remark: The Crypto1On flag can only be set by a successfully executed Authent2

command and not by the microprocessor. The microprocessor can clear bit Crypto1On to

continue with unencrypted (plain) card communication.

Remark: The Authent2 command must be executed immediately after a successful

Authent1 command; see Section 11.6.3 “Authent1 command 0Ch”. In addition, the keys

stored in the key buffer and those on the card must match.

12. Limiting values

Table 149. Limiting values

In accordance with the Absolute Maximum Rating System (IEC 60134).

Symbol

T_amb

Parameter

Conditions

Min

40

Max

Unit

C

V

ambient temperature

storage temperature

digital supply voltage

analog supply voltage

TVDD supply voltage

input voltage (absolute value)

+150

+6

T_stg

40

V_DDD

V_DDA

0.5

+6

V

V_DD(TVDD)

V_i

+6

V

on any digital pin to DVSS

on pin RX to AVSS

V_DDD+ 0.5

V_DDA+ 0.5

V

13. Characteristics

13.1 Operating condition range

Table 150. Operating condition range

Symbol

T_amb

Parameter

Conditions

Min

25

3.0

4.5

3.0

-

Typ

+25

3.3

5.0

-

Max

+85

3.6

Unit

ambient temperature

digital supply voltage

-

C

V

V_DDD

DVSS = AVSS = TVSS = 0 V

5.5

V

V_DDA

analog supply voltage

TVDD supply voltage

DVSS = AVSS = TVSS = 0 V

5.5

V

V_DD(TVDD)

V_ESD

5.5

V

electrostatic discharge voltage Human Body Model (HBM); 1.5 k,

1000

V

100 pF

Machine Model (MM); 0.75 H,

-

100

V

200 pF

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13.2 Current consumption

Table 151. Current consumption

Symbol

Parameter

Conditions

Min Typ

Max

11

Unit

mA

A

I_DDD

digital supply current

Idle command

-

8

Standby mode

3

5

Soft power-down mode

Hard power-down mode

Idle command; receiver on

Idle command; receiver off

Standby mode

800

1

1000

10

40

15

13

10

150

7

A

I_DDA

analog supply current

TVDD supply current

25

12

10

1

mA

A

Soft power-down mode

Hard power-down mode

continuous wave

1

A

I_DD(TVDD)

-

mA

pins TX1 and TX2 unconnected;

TX1RFEn and TX2RFEn = logic 1

5.5

pins TX1 and TX2 unconnected;

TX1RFEn and TX2RFEn = logic 0

-

65

130

A

13.3 Pin characteristics

13.3.1 Input pin characteristics

Pins D0 to D7, A0, and A1 have TTL input characteristics and behave as defined in

Table 152.

Table 152. Standard input pin characteristics

Symbol

I_LI

Parameter

Conditions

Min

Typ

Max

Unit

input leakage current

threshold voltage

1.0

-

+1.0

A

V

V_th

CMOS: V_DDD< 3.6 V

TTL: 4.5 < V_DDD

0.35V_DDD

0.8

0.65V_DDD

2.0

V

The digital input pins NCS, NWR, NRD, ALE, A2, and MFIN have Schmitt trigger

characteristics, and behave as defined in Table 153.

Table 153. Schmitt trigger input pin characteristics

Symbol

I_LI

Parameter

Conditions

Min

1.0

1.4

Typ

Max

+1.0

2.0

Unit

A

V

input leakage current

threshold voltage

-

V_th

positive-going threshold;

TTL = 4.5 < V_DDD

CMOS = V_DDD< 3.6 V

negative-going threshold;

TTL = 4.5 < V_DDD

0.65V_DDD

0.8

-

0.75V_DDD

1.3

V

CMOS = V_DDD< 3.6 V

0.25V_DDD

-

0.4V_DDD

V

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Pin RSTPD has Schmitt trigger CMOS characteristics. In addition, it is internally filtered by

a RC low-pass filter which causes a propagation delay on the reset signal.

Table 154. RSTPD input pin characteristics

Symbol Parameter

Conditions

Min

Typ Max

Unit

A

V

I_LI

input leakage current

1.0

-

+1.0

V_th

threshold voltage

positive-going threshold;

CMOS = V_DDD< 3.6 V

0.65V_DDD

0.75V_DDD

negative-going threshold;

CMOS = V_DDD< 3.6 V

0.25V_DDD

-

0.4V_DDD

20

V

t_PD

propagation delay

s

The analog input pin RX has the input capacitance and input voltage range shown in

Table 155.

Table 155. RX input capacitance and input voltage range

Symbol

C_i

Parameter

Conditions

Min Typ Max Unit

input capacitance

-

15

pF

V_i(dyn)

dynamic input voltage V_DDA= 5 V; T_amb= 25 C

1.1

4.4

V

13.3.2 Digital output pin characteristics

Pins D0 to D7, MFOUT and IRQ have CMOS output characteristics and behave as

defined in Table 156.

Table 156. Digital output pin characteristics

Symbol Parameter

Conditions

Min Typ Max Unit

V_OH

V_OL

I_O

HIGH-level output

voltage

V_DDD= 5 V; I_OH= 1 mA

V_DDD= 5 V; I_OH= 10 mA

V_DDD= 5 V; I_OL= 1 mA

V_DDD= 5 V; I_OL= 10 mA

source or sink; V_DDD= 5 V

2.4

4.9

4.2

25

-

V

2.4

LOW-level output

voltage

-

400 mV

250 400 mV

- 10 mA

output current

Remark: Pin IRQ can be configured as open collector which causes the V_OHvalues to be

no longer applicable.

13.3.3 Antenna driver output pin characteristics

The source conductance of the antenna driver pins TX1 and TX2 for driving the

HIGH-level can be configured using the CwConductance register’s GsCfgCW[5:0] bits,

while their source conductance for driving the LOW-level is constant.

The antenna driver default configuration output characteristics are specified in Table 157.

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Table 157. Antenna driver output pin characteristics

Symbol Parameter

Conditions

Min Typ Max Unit

V_OH

V_OL

I_O

HIGH-level output

voltage

V_DD(TVDD)= 5.0 V; I_OL= 20 mA

V_DD(TVDD)= 5.0 V; I_OL= 100 mA

V_DD(TVDD)= 5.0 V; I_OL= 20 mA

V_DD(TVDD)= 5.0 V; I_OL= 100 mA

-

4.97

4.85

30

-

V

LOW-level output

voltage

mV

150

-

output current

transmitter; continuous wave;

peak-to-peak

200 mA

13.4 AC electrical characteristics

13.4.1 Separate read/write strobe bus timing

Table 158. Timing specification for separate read/write strobe

Symbol

t_LHLL

Parameter

Conditions

Min Typ Max Unit

ALE HIGH time

20

15

8

-

ns

t_AVLL

address valid to ALE LOW time

t_LLAX

address hold after ALE LOW

time

t_LLRWL

t_SLRWL

t_RWHSH

t_RLDV

ALE LOW to read/write LOW

time

ALE LOW to NRD or

NWR LOW

15

0

-

ns

chip select LOW to read/write NCS LOW to NRD or

LOW time NWR LOW

-

read/write HIGH to chip select NRD or NWR HIGH to

HIGH time

-

NCS HIGH

read LOW to data input valid

time

NRD LOW to data valid

65

20

35

-

t_RHDZ

read HIGH to data input high

impedance time

NRD HIGH to data

high-impedance

-

t_WLQV

t_WHDX

write LOW to data output valid NWR LOW to data valid

time

-

data output hold after write

HIGH time

data hold time after

NWR HIGH

8

t_RWLRWH

t_AVRWL

read/write LOW time

NRD or NWR

65

30

-

ns

address valid to read/write

LOW time

NRD or NWR LOW

(set-up time)

t_WHAX

address hold after write HIGH NWR HIGH (hold time)

time

8

-

ns

t_RWHRWL

read/write HIGH time

150

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t

LHLL

ALE

t

RWHSH

SLRWL

NCS

t

LLRWL

t

RWHRWL

RWLRWH

NWR

NRD

t

WHDX

WLQV

t

LLAX

AVLL

t

RLDV

RHDZ

D0 to D7

A0 to A2

D0 to D7

Multiplexed address bus

t

WHAX

AVRWL

A0 to A2

Separated address bus

001aaj638

Fig 20. Separate read/write strobe timing diagram

Remark: The signal ALE is not relevant for separate address/data bus and the

multiplexed addresses on the data bus do not care. The multiplexed address and data bus

address lines (A0 to A2) must be connected as described in Section 9.1.3 on page 8.

13.4.2 Common read/write strobe bus timing

Table 159. Common read/write strobe timing specification

Symbol

t_LHLL

Parameter

Conditions

Min Typ Max Unit

ALE HIGH time

20

15

8

-

ns

t_AVLL

address valid to ALE LOW time

address hold after ALE LOW time

t_LLAX

t_LLDSL

ALE LOW to data strobe LOW time NWR or NRD

LOW

15

t_SLDSL

chip select LOW to data strobe

LOW time

NCS LOW to

NDS LOW

0

-

ns

t_DSHSH

t_DSLDV

t_DSHDZ

t_DSLQV

t_DSHQX

t_DSHRWX

t_DSLDSH

data strobe HIGH to chip select

HIGH time

-

data strobe LOW to data input valid

time

65

20

35

-

data strobe HIGH to data input high

impedance time

-

data strobe LOW to data output

valid time

NDS/NCS LOW

-

data output hold after data strobe

HIGH time

NDS HIGH (write

cycle hold time)

8

65

RW hold after data strobe HIGH

time

after NDS HIGH

-

data strobe LOW time

NDS/NCS

-

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Table 159. Common read/write strobe timing specification …continued

Symbol

Parameter

Conditions

Min Typ Max Unit

t_AVDSL

address valid to data strobe LOW

time

30

-

ns

t_RHAX

address hold after read HIGH time

data strobe HIGH time

8

-

ns

t_DSHDSL

period between

write sequences

150

t_WLDSL

write LOW to data strobe LOW time R/NW valid to

NDS LOW

8

-

ns

t

LHLL

ALE

t

DSHSH

SLDSL

NCS/NDS

R/NW

t

DSHRWX

WLDSL

t

LLDSL

t

DSHDSL

DSLDSH

NRD

D0 to D7

A0 to A2

t

DSHQX

DSLDV

t

LLAX

AVLL

t

DSLQV

DSHDZ

A0 to A2

D0 to D7

Multiplexed address bus

t

RHAX

AVDSL

A0 to A2

Separated address bus

001aaj639

Fig 21. Common read/write strobe timing diagram

13.4.3 EPP bus timing

Table 160. Common read/write strobe timing specification for EPP

Symbol

t_ASLASH

t_AVASH

Parameter

Conditions

Min Typ Max Unit

address strobe LOW time

nAStrb

20

15

-

ns

address valid to address strobe

HIGH time

multiplexed address

bus set-up time

t_ASHAV

t_SLDSL

t_DSHSH

t_DSLDV

address valid after address strobe

HIGH time

multiplexed address

bus hold time

8

0

-

ns

chip select LOW to data strobe

LOW time

NCS LOW to nDStrb

LOW

-

data strobe HIGH to chip select

HIGH time

nDStrb HIGH to

NCS HIGH

-

data strobe LOW to data input valid read cycle

time

65

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Table 160. Common read/write strobe timing specification for EPP …continued

Symbol Parameter Conditions Min Typ Max Unit

t_DSHDZ

t_DSLQV

t_DSHQX

t_DSHWX

data strobe HIGH to data input high read cycle

impedance time

-

20

35

-

ns

data strobe LOW to data output

valid time

nDStrb LOW

NCS HIGH

nWrite

-

data output hold after data strobe

HIGH time

8

write hold after data strobe HIGH

time

-

t_DSLDSH

t_WLDSL

data strobe LOW time

nDStrb

65

8

-

ns

write LOW to data strobe LOW time nWrite valid to

nDStrb LOW

t_DSL-WAITHdata strobe LOW to WAIT HIGH

time

nDStrb LOW to

nWrite HIGH

-

75

ns

t_DSH-WAITLdata strobe HIGH to WAIT LOW

time

nDStrb HIGH to

nWrite LOW

t

DSHSH

t

SLDSL

NCS

t

DSHWX

WLDSL

nWrite

t

DSLDSH

nDStrb

nAStrb

t

DSLDV

DSHQX

DSHDZ

t

DSLQV

D0 to D7

A0 to A7

D0 to D7

nWait

t

DSH-WAITL

DSL-WAITH

001aaj640

Fig 22. Timing diagram for common read/write strobe; EPP

Remark: Figure 22 does not distinguish between the address write cycle and a data write

cycle. The timings for the address write and data write cycle are different. In EPP mode,

the address lines (A0 to A2) must be connected as described in Section 9.1.3 on page 8.

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13.4.4 SPI timing

Table 161. SPI timing specification

Symbol

t_SCKL

Parameter

Conditions

Min Typ Max Unit

SCK LOW time

SCK HIGH time

100

20

-

ns

t_SCKH

t_DSHQX

data output hold after data strobe

HIGH time

t_DQXCH

data input/output changing to clock

HIGH time

20

-

ns

t_h(SCKL-Q)

SCK LOW to data output hold time

-

15

-

ns

t_(SCKL-NSSH)SCK LOW to NSS HIGH time

20

t

SCKL

NSSH

SCKL

SCKH

SCK

t

h(SCKL-Q)

t

h(SCKH-D)

t

h(SCKL-Q)

su(D-SCKH)

OSI

ISO

MSB

LSB

MSB

LSB

t

(SCKL-NSSH)

NSS

001aaj64

Fig 23. Timing diagram for SPI

Remark: To send more bytes in one data stream the NSS signal must be LOW during the

send process. To send more than one data stream the NSS signal must be HIGH between

each data stream.

13.4.5 Clock frequency

The clock input is pin OSCIN.

Table 162. Clock frequency

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

f_clk

clock frequency

checked by the clock

filter

-

13.56

-

MHz

_clk

clock duty cycle

jitter time

40

-

50

-

60

10

%

t_jit

of clock edges

ps

The clock applied to the MFRC531 acts as a time constant for the synchronous system’s

encoder and decoder. The stability of the clock frequency is an important factor for

ensuring proper performance. To obtain highest performance, clock jitter must be as small

as possible. This is best achieved using the internal oscillator buffer and the

recommended circuitry; see Section 9.8 on page 29.

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14. EEPROM characteristics

The EEPROM size is 32  16  8 = 4096 bit.

Table 163. EEPROM characteristics

Symbol Parameter

N_{endu(W_ER)}write or erase endurance erase/write cycles

Conditions

Min

Typ Max

Unit

Hz

100.000

-

t_ret

retention time

erase time

T_amb 55 C

10

-

year

ms

t_er

2.9

t_a(W)

write access time

-

ms

15. Application information

15.1 Typical application

15.1.1 Circuit diagram

Figure 24 shows a typical application where the antenna is directly matched to the

MFRC531:

DVDD

Reset

AVDD

TVDD

RSTPD

control lines

data bus

C1

L0

TX1

MICROPROCESSOR

BUS

C0

C2a

C2b

C3

MICROPROCESSOR

TVSS

TX2

C1

R1

MFRC531

IRQ

RX

R2

VMID

DVSS

OSCIN

OSCOUT AVSS

13.56 MHz

C4

100 nF

15 pF

001aal225

Fig 24. Application example circuit diagram: directly matched antenna

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15.1.2 Circuit description

The matching circuit consists of an EMC low-pass filter (L0 and C0), matching circuitry

(C1 and C2n), a receiver circuit (R1, R2, C3 and C4) and the antenna itself.

Refer to the following application notes for more detailed information about designing and

tuning an antenna.

• MICORE reader IC family; Directly Matched Antenna Design Ref. 1

• MIFARE (14443 A) 13.56 MHz RFID Proximity Antennas Ref. 2.

15.1.2.1 EMC low-pass filter

The MIFARE system operates at a frequency of 13.56 MHz. This frequency is generated

by a quartz oscillator to clock the MFRC531. It is also the basis for driving the antenna

using the 13.56 MHz energy carrier. This not only causes power emissions at 13.56 MHz,

it also emits power at higher harmonics. International EMC regulations define the

amplitude of the emitted power over a broad frequency range. To meet these regulations,

appropriate filtering of the output signal is required.

A multilayer board is recommended to implement a low-pass filter as shown in Figure 24.

The low-pass filter consists of the components L0 and C0. The recommended values are

given in Application notes MICORE reader IC family; Directly Matched Antenna Design

Ref. 1 and MIFARE (14443 A) 13.56 MHz RFID Proximity Antennas Ref. 2.

Remark: To achieve best performance, all components must be at least equal in quality to

those recommended.

Remark: The layout has a major influence on the overall performance of the filter.

15.1.2.2 Antenna matching

Due to the impedance transformation of the low-pass filter, the antenna coil has to be

matched to a given impedance. The matching elements C1 and C2n can be estimated

and have to be fine tuned depending on the design of the antenna coil.

The correct impedance matching is important to ensure optimum performance. The

overall quality factor has to be considered to guarantee a proper ISO/IEC 14443 A and

ISO/IEC 14443 B communication schemes. Environmental influences have to considered

and common EMC design rules.

Refer to Application notes MICORE reader IC family; Directly Matched Antenna Design

Ref. 1 and MIFARE (14443 A) 13.56 MHz RFID Proximity Antennas Ref. 2 for details.

Remark: Do not exceed the current limits (I_DD(TVDD)), otherwise the chip might be

destroyed.

Remark: The overall 13.56 MHz RFID proximity antenna design in combination with the

MFRC531 IC does not require any specialist RF knowledge. However, all relevant

parameters have to be considered to guarantee optimum performance and international

EMC compliance.

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15.1.2.3 Receiver circuit

The internal receiver of the MFRC531 makes use of both subcarrier load modulation

side-bands. No external filtering is required.

It is recommended to use the internally generated VMID potential as the input potential for

pin RX. This VMID DC voltage level has to be coupled to pin RX using resistor (R2). To

provide a stable DC reference voltage, capacitor (C4) must be connected between VMID

and ground.

The AC voltage divider of R1 + C3 and R2 has to be designed taking in to account the AC

voltage limits on pin RX. Depending on the antenna coil design and the impedance,

matching the voltage at the antenna coil will differ. Therefore the recommended way to

design the receiver circuit is to use the given values for R1, R2, and C3; refer to

Application note; MIFARE (14443 A) 13.56 MHz RFID Proximity Antennas Ref. 2. The

voltage on pin RX can be altered by varying R1 within the given limits.

Remark: R2 is AC connected to ground using C4.

15.1.2.4 Antenna coil

The precise calculation of the antenna coil’s inductance is not practicable but the

inductance can be estimated using Equation 10. We recommend designing an antenna

that is either circular or rectangular.

I₁

1.8





------

L₁nH = 2  I₁cm  ln   – K N₁

(10)





D₁

• l₁= length of one turn of the conductor loop

• D₁= diameter of the wire or width of the PCB conductor, respectively

• K = antenna shape factor (K = 1.07 for circular antennas and K = 1.47 for square

antennas)

• N₁= number of turns

• ln = natural logarithm function

The values of the antenna inductance, resistance, and capacitance at 13.56 MHz depend

on various parameters such as:

• antenna construction (type of PCB)

• thickness of conductor

• distance between the windings

• shielding layer

• metal or ferrite nearby in the environment

Therefore, a measurement of these parameters under real life conditions or at least a

rough measurement and a tuning procedure is highly recommended to guarantee a

reasonable performance. Refer to Application notes MICORE reader IC family; Directly

Matched Antenna Design Ref. 1 and MIFARE (14443 A) 13.56 MHz RFID Proximity

Antennas Ref. 2 for details.

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15.2 Test signals

The MFRC531 allows different kinds of signal measurements. These measurements can

be used to check the internally generated and received signals using the serial signal

switch as described in Section 9.11 on page 35.

In addition, the MFRC531 enables users to select between:

• internal analog signals for measurement on pin AUX

• internal digital signals for observation on pin MFOUT (based on register selections)

These measurements can be helpful during the design-in phase to optimize the receiver’s

behavior or for test purposes.

15.2.1 Measurements using the serial signal switch

Using the serial signal switch on pin MFOUT, data is observed that is sent to the card or

received from the card. Table 164 gives an overview of the different signals available.

Table 164. Signal routed to pin MFOUT

SignalToMFOUT

MFOUTSelect[2:0]

Signal routed to pin MFOUT

LOW

0

1

000

001

010

011

100

101

110

111

X

HIGH

envelope

transmit NRZ

Manchester with subcarrier

Manchester

reserved

digital test signal

Remark: The routing of the Manchester or the Manchester with subcarrier signal to pin

MFOUT is only possible at 106 kBd based on ISO/IEC 14443 A.

15.2.1.1 TX control

Figure 25 shows as an example of an ISO/IEC 14443 A communication.

The signal is measured on pin MFOUT using the serial signal switch to control the data

sent to the card. Setting the flag MFOUTSelect[2:0] = 010 sends the data to the card

coded as NRZ. Setting MFOUTSelect[2:0] = 001 shows the data as a Miller coded signal.

The RFOut signal is measured directly on the antenna and gives the RF signal pulse

shape. Refer to Application note Directly matched Antenna - Excel calculation (Ref. 3) for

detail information on the RF signal pulse.

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(1)

(2)

(3)

10 μs per division

001aak626

(1) MFOUTSelect[2:0] = 001; serial data stream; 2 V per division.

(2) MFOUTSelect[2:0] = 010; serial data stream; 2 V per division.

(3) RFOut; 1 V per division.

Fig 25. TX control signals

15.2.1.2 RX control

Figure 26 shows an example of ISO/IEC 14443 A communication which represents the

beginning of a card’s answer to a request signal.

The RF signal shows the RF voltage measured directly on the antenna so that the card’s

load modulation is visible. Setting MFOUTSelect[2:0] = 011 shows the Manchester

decoded signal with subcarrier. Setting MFOUTSelect[2:0] = 100 shows the Manchester

decoded signal.

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(1)

(2)

(3)

10 μs per division

001aak627

(1) RFOut; 1 V per division.

(2) MFOUTSelect[2:0] = 011; Manchester with subcarrier; 2 V per division.

(3) MFOUTSelect[2:0] = 100; Manchester; 2 V per division.

Fig 26. RX control signals

15.2.2 Analog test signals

The analog test signals can be routed to pin AUX by selecting them using the

TestAnaSelect register TestAnaOutSel[4:0] bits.

Table 165. Analog test signal selection

Value Signal Name Description

0

1

2

3

4

5

6

VMID

voltage at internal node VMID

Vbandgap

VRxFollI

VRxFollQ

VRxAmpI

VRxAmpQ

VCorrNI

internal reference voltage generated by the bandgap

output signal from the demodulator using the I-clock

output signal from the demodulator using the Q-clock

I-channel subcarrier signal amplified and filtered

Q-channel subcarrier signal amplified and filtered

output signal of N-channel correlator fed by the I-channel subcarrier

signal

7

8

9

A

VCorrNQ

VCorrDI

VCorrDQ

VEvalL

output signal of N-channel correlator fed by the Q-channel subcarrier

signal

output signal of D-channel correlator fed by the I-channel subcarrier

signal

output signal of D-channel correlator fed by the Q-channel subcarrier

signal

evaluation signal from the left half-bit

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Table 165. Analog test signal selection …continued

Value Signal Name Description

B

C

D

E

F

VEvalR

VTemp

evaluation signal from the right half-bit

temperature voltage derived from band gap

reserved for future use

reserved

reserved for future use

15.2.3 Digital test signals

Digital test signals can be routed to pin MFOUT by setting bit SignalToMFOUT = logic 1. A

digital test signal is selected using the TestDigiSelect register TestDigiSignalSel[6:0] bits.

The signals selected by the TestDigiSignalSel[6:0] bits are shown in Table 166.

Table 166. Digital test signal selection

TestDigiSignalSel Signal name Description

[6:0]

F4h

E4h

s_data

s_valid

data received from the card

when logic 1 is returned the s_data and s_coll signals are

valid

D4h

C4h

s_coll

when logic 1 is returned a collision has been detected in the

current bit

s_clock

internal serial clock:

during transmission, this is the encoder clock

during reception this is the receiver clock

B5h

A5h

rd_sync

wr_sync

internal synchronized read signal which is derived from the

parallel microprocessor interface

internal synchronized write signal which is derived from the

parallel microprocessor interface

96h

83h

E2h

00h

int_clock

internal 13.56 MHz clock

BPSK output signal

BPSK_out

BPSK_sig

BPSK signal’s amplitude detected

no test signal output as defined by the MFOUTSelect register

MFOUTSelect[2:0] bits routed to pin MFOUT

If test signals are not used, the TestDigiSelect register address value must be 00h.

Remark: All other values for TestDigiSignalSel[6:0] are for production test purposes only.

15.2.4 Examples of ISO/IEC 14443 A analog and digital test signals

Figure 27 shows a MIFARE card’s answer to a request command using the Q-clock

receiving path. RX reference is given to show the Manchester modulated signal on pin

RX.

The signal is demodulated and amplified in the receiver circuitry. Signal VRXAmpQ is the

amplified side-band signal using the Q-clock for demodulation. The signals VCorrDQ and

VCorrNQ were generated in the correlation circuitry. They are processed further in the

evaluation and digitizer circuitry.

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Signals VEvalR and VEvalL show the evaluation of the signal’s right and left half-bit.

Finally, the digital test signal s_data shows the received data. This is then sent to the

internal digital circuit and s_valid which indicates the received data stream is valid.

RX reference

VRxAmpQ

VCorrDQ

VCorrNQ

VEvalR

VEvalL

s_data

s_valid

50 μs per division

001aak628

Fig 27. ISO/IEC 14443 A receiving path Q-clock

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16. Package outline

SO32: plastic small outline package; 32 leads; body width 7.5 mm

SOT287-1

D

E

A

X

c

y

H

v

M

A

E

Z

17

32

Q

A

2

A

(A )

3

A

1

pin 1 index

θ

L

p

L

16

1

w

M

detail X

b

p

e

0

5

10 mm

scale

DIMENSIONS (inch dimensions are derived from the original mm dimensions)

A

(1)

UNIT

A

b

c

D

E

e

H

E

L

Q

v

w

y

Z

θ

p

1

2

3

max.

0.3

0.1

2.45

2.25

0.49

0.36

0.27 20.7

0.18 20.3

7.6

7.4

10.65

10.00

1.1

0.4

1.2

1.0

0.95

0.55

mm

2.65

0.25

0.01

1.27

0.05

1.4

0.25

0.01

0.25

0.01

0.1

8^o

0^o

0.012 0.096

0.004 0.089

0.02 0.011 0.81

0.01 0.007 0.80

0.30

0.29

0.419

0.394

0.043 0.047

0.016 0.039

0.037

0.022

inches

0.1

0.004

0.055

Note

1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included.

REFERENCES

OUTLINE

EUROPEAN

PROJECTION

ISSUE DATE

VERSION

IEC

JEDEC

JEITA

00-08-17

03-02-19

SOT287-1

MO-119

Fig 28. Package outline SOT287-1

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17. Abbreviations

Table 167. Abbreviations and acronyms

Acronym

Description

ASK

BPSK

CMOS

CRC

EOF

EPP

ETU

FIFO

HBM

LSB

Amplitude-Shift Keying

Binary Phase-Shift Keying

Complementary Metal-Oxide Semiconductor

Cyclic Redundancy Check

End Of Frame

Enhanced Parallel Port

Elementary Time Unit

First In, First Out

Human Body Model

Least Significant Bit

MM

Machine Model

MSB

NRZ

POR

PCD

PICC

SOF

SPI

Most Significant Bit

None Return to Zero

Power-On Reset

Proximity Coupling Device

Proximity Integrated Circuit Card

Start Of Frame

Serial Peripheral Interface

18. References

[1] Application note — MICORE reader IC family; Directly Matched Antenna Design.

[2] Application note — MIFARE (14443 A) 13.56 MHz RFID Proximity Antennas.

[3] Application note — Directly matched Antenna - Excel calculation.

[4] ISO standard — ISO/IEC 14443 Identification cards - Contactless integrated

circuit(s) cards - Proximity cards, part 1-4.

[5] Application note — MIFARE Implementation of Higher Baud rates.

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19. Revision history

Table 168. Revision history

Document ID

MFRC531 v. 3.6 20140227

Modifications:

MFRC531 v. 3.5 20140203

Release date

Data sheet status

Change notice

Supersedes

Product data sheet

-

MFRC531 v. 3.5

Section 2 “General description”: 1^stparagraph updated

Product data sheet

-

MFRC531_34

Modifications:

• Section 2 “General description”: updated

• Change of descriptive title

MFRC531_34

Modifications:

20100126

Product data sheet

056633

• The format of this data sheet has been redesigned to comply with the new identity guidelines of

NXP Semiconductors

• Legal texts have been adapted to the new company name where appropriate

• The symbols for electrical characteristics and their parameters have been updated to meet the

NXP Semiconductors’ guidelines

• A number of inconsistencies in pin, register and bit names have been eliminated from the data sheet

• All drawings have been updated

• Several symbol changes made to drawings in Figure 23 on page 97 to Figure 26 “RX control signals”

on page 103

• Section 5 “Quick reference data” on page 3: section added

• Section 6 “Ordering information” on page 3: updated

• Section 15.1.2.4 “Antenna coil” on page 100: added missing formula and updated the last clause

• Section 16 “Package outline” on page 106: updated

• Data sheet security status changed from COMPANY CONFIDENTIAL to COMPANY PUBLIC

• RATP/Innovatron Technologies license statement added to the legal page

056633

056632

056631

056630

056620

056610

December 2005

Product data sheet

Preliminary data sheet

Objective data sheet

056632

056631

056630

056620

056610

-

April 2005

May 2004

November 2002

January 2002

July 2001

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20. Legal information

20.1 Data sheet status

Document status^[1][2]

Product status^[3]

Development

Definition

Objective [short] data sheet

This document contains data from the objective specification for product development.

This document contains data from the preliminary specification.

This document contains the product specification.

Preliminary [short] data sheet Qualification

Product [short] data sheet Production

[1]

[2]

[3]

Please consult the most recently issued document before initiating or completing a design.

The term ‘short data sheet’ is explained in section “Definitions”.

The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status

information is available on the Internet at URL http://www.nxp.com.

Suitability for use — NXP Semiconductors products are not designed,

20.2 Definitions

authorized or warranted to be suitable for use in life support, life-critical or

safety-critical systems or equipment, nor in applications where failure or

malfunction of an NXP Semiconductors product can reasonably be expected

to result in personal injury, death or severe property or environmental

damage. NXP Semiconductors and its suppliers accept no liability for

inclusion and/or use of NXP Semiconductors products in such equipment or

applications and therefore such inclusion and/or use is at the customer’s own

risk.

Draft — The document is a draft version only. The content is still under

internal review and subject to formal approval, which may result in

modifications or additions. NXP Semiconductors does not give any

representations or warranties as to the accuracy or completeness of

information included herein and shall have no liability for the consequences of

use of such information.

Short data sheet — A short data sheet is an extract from a full data sheet

with the same product type number(s) and title. A short data sheet is intended

for quick reference only and should not be relied upon to contain detailed and

full information. For detailed and full information see the relevant full data

sheet, which is available on request via the local NXP Semiconductors sales

office. In case of any inconsistency or conflict with the short data sheet, the

full data sheet shall prevail.

Applications — Applications that are described herein for any of these

products are for illustrative purposes only. NXP Semiconductors makes no

representation or warranty that such applications will be suitable for the

specified use without further testing or modification.

Customers are responsible for the design and operation of their applications

and products using NXP Semiconductors products, and NXP Semiconductors

accepts no liability for any assistance with applications or customer product

design. It is customer’s sole responsibility to determine whether the NXP

Semiconductors product is suitable and fit for the customer’s applications and

products planned, as well as for the planned application and use of

customer’s third party customer(s). Customers should provide appropriate

design and operating safeguards to minimize the risks associated with their

applications and products.

Product specification — The information and data provided in a Product

data sheet shall define the specification of the product as agreed between

NXP Semiconductors and its customer, unless NXP Semiconductors and

customer have explicitly agreed otherwise in writing. In no event however,

shall an agreement be valid in which the NXP Semiconductors product is

deemed to offer functions and qualities beyond those described in the

Product data sheet.

NXP Semiconductors does not accept any liability related to any default,

damage, costs or problem which is based on any weakness or default in the

customer’s applications or products, or the application or use by customer’s

third party customer(s). Customer is responsible for doing all necessary

testing for the customer’s applications and products using NXP

Semiconductors products in order to avoid a default of the applications and

the products or of the application or use by customer’s third party

customer(s). NXP does not accept any liability in this respect.

20.3 Disclaimers

Limited warranty and liability — Information in this document is believed to

be accurate and reliable. However, NXP Semiconductors does not give any

representations or warranties, expressed or implied, as to the accuracy or

completeness of such information and shall have no liability for the

consequences of use of such information. NXP Semiconductors takes no

responsibility for the content in this document if provided by an information

source outside of NXP Semiconductors.

Limiting values — Stress above one or more limiting values (as defined in

the Absolute Maximum Ratings System of IEC 60134) will cause permanent

damage to the device. Limiting values are stress ratings only and (proper)

operation of the device at these or any other conditions above those given in

the Recommended operating conditions section (if present) or the

Characteristics sections of this document is not warranted. Constant or

repeated exposure to limiting values will permanently and irreversibly affect

the quality and reliability of the device.

In no event shall NXP Semiconductors be liable for any indirect, incidental,

punitive, special or consequential damages (including - without limitation - lost

profits, lost savings, business interruption, costs related to the removal or

replacement of any products or rework charges) whether or not such

damages are based on tort (including negligence), warranty, breach of

contract or any other legal theory.

Terms and conditions of commercial sale — NXP Semiconductors

products are sold subject to the general terms and conditions of commercial

sale, as published at http://www.nxp.com/profile/terms, unless otherwise

agreed in a valid written individual agreement. In case an individual

agreement is concluded only the terms and conditions of the respective

agreement shall apply. NXP Semiconductors hereby expressly objects to

applying the customer’s general terms and conditions with regard to the

purchase of NXP Semiconductors products by customer.

Notwithstanding any damages that customer might incur for any reason

whatsoever, NXP Semiconductors’ aggregate and cumulative liability towards

customer for the products described herein shall be limited in accordance

with the Terms and conditions of commercial sale of NXP Semiconductors.

Right to make changes — NXP Semiconductors reserves the right to make

changes to information published in this document, including without

limitation specifications and product descriptions, at any time and without

notice. This document supersedes and replaces all information supplied prior

to the publication hereof.

No offer to sell or license — Nothing in this document may be interpreted or

construed as an offer to sell products that is open for acceptance or the grant,

conveyance or implication of any license under any copyrights, patents or

other industrial or intellectual property rights.

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Export control — This document as well as the item(s) described herein

may be subject to export control regulations. Export might require a prior

authorization from competent authorities.

20.4 Licenses

Purchase of NXP ICs with ISO/IEC 14443 type B functionality

Quick reference data — The Quick reference data is an extract of the

product data given in the Limiting values and Characteristics sections of this

document, and as such is not complete, exhaustive or legally binding.

This NXP Semiconductors IC is ISO/IEC 14443 Type B

software enabled and is licensed under Innovatron’s

Contactless Card patents license for ISO/IEC 14443 B.

Non-automotive qualified products — Unless this data sheet expressly

states that this specific NXP Semiconductors product is automotive qualified,

the product is not suitable for automotive use. It is neither qualified nor tested

in accordance with automotive testing or application requirements. NXP

Semiconductors accepts no liability for inclusion and/or use of

The license includes the right to use the IC in systems

and/or end-user equipment.

RATP/Innovatron

Technology

non-automotive qualified products in automotive equipment or applications.

In the event that customer uses the product for design-in and use in

automotive applications to automotive specifications and standards, customer

(a) shall use the product without NXP Semiconductors’ warranty of the

product for such automotive applications, use and specifications, and (b)

whenever customer uses the product for automotive applications beyond

NXP Semiconductors’ specifications such use shall be solely at customer’s

own risk, and (c) customer fully indemnifies NXP Semiconductors for any

liability, damages or failed product claims resulting from customer design and

use of the product for automotive applications beyond NXP Semiconductors’

standard warranty and NXP Semiconductors’ product specifications.

20.5 Trademarks

Notice: All referenced brands, product names, service names and trademarks

are the property of their respective owners.

MIFARE — is a trademark of NXP Semiconductors N.V.

MIFARE Ultralight — is a trademark of NXP Semiconductors N.V.

MIFARE Plus — is a trademark of NXP Semiconductors N.V.

DESFire — is a trademark of NXP Semiconductors N.V.

Translations — A non-English (translated) version of a document is for

reference only. The English version shall prevail in case of any discrepancy

between the translated and English versions.

21. Contact information

For more information, please visit: http://www.nxp.com

For sales office addresses, please send an email to: salesaddresses@nxp.com

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MFRC531

NXP Semiconductors

Standard ISO/IEC 14443 A/B reader solution

22. Tables

Table 1. Quick reference data . . . . . . . . . . . . . . . . . . . . .3

Table 2. Ordering information . . . . . . . . . . . . . . . . . . . . .3

Table 3. Pin description . . . . . . . . . . . . . . . . . . . . . . . . . .5

Table 4. Supported microprocessor and EPP interface

signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Table 39. Page register (address: 00h, 08h, 10h, 18h, 20h,

28h, 30h, 38h) reset value: 1000 0000b, 80h bit

allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Table 40. Page register bit descriptions . . . . . . . . . . . . . 48

Table 41. Command register (address: 01h) reset value:

x000 0000b, x0h bit allocation . . . . . . . . . . . . 48

Table 42. Command register bit descriptions . . . . . . . . . 48

Table 43. FIFOData register (address: 02h) reset value:

xxxx xxxxb, 05h bit allocation . . . . . . . . . . . . . 49

Table 44. FIFOData register bit descriptions . . . . . . . . . 49

Table 45. PrimaryStatus register (address: 03h) reset value:

0000 0101b, 05h bit allocation . . . . . . . . . . . . 49

Table 46. PrimaryStatus register bit descriptions . . . . . . 49

Table 47. FIFOLength register (address: 04h) reset value:

0000 0000b, 00h bit allocation . . . . . . . . . . . . 50

Table 48. FIFOLength bit descriptions . . . . . . . . . . . . . . 50

Table 49. SecondaryStatus register (address: 05h) reset

value: 01100 000b, 60h bit allocation . . . . . . . 51

Table 50. SecondaryStatus register bit descriptions . . . . 51

Table 51. InterruptEn register (address: 06h) reset value:

0000 0000b, 00h bit allocation . . . . . . . . . . . . 51

Table 52. InterruptEn register bit descriptions . . . . . . . . 51

Table 53. InterruptRq register (address: 07h) reset value:

0000 0000b, 00h bit allocation . . . . . . . . . . . . 52

Table 54. InterruptRq register bit descriptions . . . . . . . . 52

Table 55. Control register (address: 09h) reset value: 0000

0000b, 00h bit allocation . . . . . . . . . . . . . . . . . 53

Table 5. Connection scheme for detecting the parallel

interface type . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Table 6. SPI compatibility . . . . . . . . . . . . . . . . . . . . . . .10

Table 7. SPI read data . . . . . . . . . . . . . . . . . . . . . . . . . .10

Table 8. SPI read address . . . . . . . . . . . . . . . . . . . . . . .11

Table 9. SPI write data . . . . . . . . . . . . . . . . . . . . . . . . .11

Table 10. SPI write address . . . . . . . . . . . . . . . . . . . . . .11

Table 11. EEPROM memory organization diagram . . . . .12

Table 12. Product information field . . . . . . . . . . . . . . . . .13

Table 13. Product type identification definition . . . . . . . .13

Table 14. Byte assignment for register initialization at

start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Table 15. Shipment content of StartUp configuration file .15

Table 16. Byte assignment for register initialization at

startup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Table 17. FIFO buffer access . . . . . . . . . . . . . . . . . . . . .17

Table 18. Associated FIFO buffer registers and flags . . .19

Table 19. Interrupt sources . . . . . . . . . . . . . . . . . . . . . . .20

Table 20. Interrupt control registers . . . . . . . . . . . . . . . .20

Table 21. Associated Interrupt request system registers

and flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

Table 22. Associated timer unit registers and flags . . . . .25

Table 23. Signal on pins during Hard power-down . . . . .26

Table 24. Pin TX1 configurations . . . . . . . . . . . . . . . . . .29

Table 25. Pin TX2 configurations . . . . . . . . . . . . . . . . . .30

Table 26. TX1 and TX2 source resistance of n-channel

driver transistor against GsCfgCW

Table 56. Control register bit descriptions . . . . . . . . . . . 53

Table 57. ErrorFlag register (address: 0Ah) reset value:

0100 0000b, 40h bit allocation . . . . . . . . . . . . 53

Table 58. ErrorFlag register bit descriptions . . . . . . . . . . 53

Table 59. CollPos register (address: 0Bh) reset value: 0000

0000b, 00h bit allocation . . . . . . . . . . . . . . . . . 54

or GsCfgMod . . . . . . . . . . . . . . . . . . . . . . . . . .31

Table 27. Gain factors for the internal amplifier . . . . . . . .34

Table 28. DecoderSource[1:0] values . . . . . . . . . . . . . . .37

Table 29. ModulatorSource[1:0] values . . . . . . . . . . . . . .37

Table 30. MFOUTSelect[2:0] values . . . . . . . . . . . . . . . .37

Table 31. Register settings to enable use of the analog

circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Table 60. CollPos register bit descriptions . . . . . . . . . . . 54

Table 61. TimerValue register (address: 0Ch) reset value:

xxxx xxxxb, xxh bit allocation . . . . . . . . . . . . . 55

Table 62. TimerValue register bit descriptions . . . . . . . . 55

Table 63. CRCResultLSB register (address: 0Dh) reset

value: xxxx xxxxb, xxh bit allocation . . . . . . . . 55

Table 32. MIFARE higher baud rates . . . . . . . . . . . . . . .38

Table 33. ISO/IEC 14443 B registers and flags . . . . . . . .39

Table 34. Dedicated address bus: assembling the register

address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Table 35. Multiplexed address bus: assembling the register

address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Table 64. CRCResultLSB register bit descriptions . . . . . 55

Table 65. CRCResultMSB register (address: 0Eh) reset

value: xxxx xxxxb, xxh bit allocation . . . . . . . . 55

Table 66. CRCResultMSB register bit descriptions . . . . 55

Table 67. BitFraming register (address: 0Fh) reset value:

0000 0000b, 00h bit allocation . . . . . . . . . . . . 56

Table 36. Behavior and designation of register bits . . . . .42

Table 37. MFRC531 register overview . . . . . . . . . . . . . .43

Table 38. MFRC531 register flags overview . . . . . . . . . .45

Table 68. BitFraming register bit descriptions . . . . . . . . . 56

Table 69. TxControl register (address: 11h) reset value:

0101 1000b, 58h bit allocation . . . . . . . . . . . . 57

continued >>

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Product data sheet

COMPANY PUBLIC

Rev. 3.6 — 27 February 2014

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MFRC531

NXP Semiconductors

Standard ISO/IEC 14443 A/B reader solution

Table 70. TxControl register bit descriptions . . . . . . . . . .57

Table 71. CwConductance register (address: 12h) reset

value: 0011 1111b, 3Fh bit allocation . . . . . . . .58

Table 72. CwConductance register bit descriptions . . . .58

Table 73. ModConductance register (address: 13h) reset

value: 0011 1111b, 3Fh bit allocation . . . . . . . .58

Table 74. ModConductance register bit descriptions . . . .58

Table 75. CoderControl register (address: 14h) reset value:

0001 1001b, 19h bit allocation . . . . . . . . . . . . .59

Table 104. PreSet25 register (address: 25h) reset value:

0000 0000b, 00h bit allocation . . . . . . . . . . . . 66

Table 105. MFOUTSelect register (address: 26h) reset

value: 0000 0000b, 00h bit allocation . . . . . . . 67

Table 106. MFOUTSelect register bit descriptions . . . . . 67

Table 107. PreSet27 (address: 27h) reset value: xxxx xxxxb,

xxh bit allocation . . . . . . . . . . . . . . . . . . . . . . . 67

Table 108. FIFOLevel register (address: 29h) reset value:

0000 1000b, 08h bit allocation . . . . . . . . . . . . 68

Table 76. CoderControl register bit descriptions . . . . . . .59

Table 77. ModWidth register (address: 15h) reset value:

0001 0011b, 13h bit allocation . . . . . . . . . . . . .59

Table 109. FIFOLevel register bit descriptions . . . . . . . . 68

Table 110. TimerClock register (address: 2Ah) reset value:

0000 0111b, 07h bit allocation . . . . . . . . . . . . . 68

Table 78. ModWidth register bit descriptions . . . . . . . . . .59

Table 79. PreSet16 register (address: 16h) reset value:

0000 0000b, 00h bit allocation . . . . . . . . . . . . .59

Table 111. TimerClock register bit descriptions . . . . . . . . 68

Table 112. TimerControl register (address: 2Bh) reset value:

0000 0110b, 06h bit allocation . . . . . . . . . . . . 69

Table 80. TypeBFraming register (address: 17h) reset

value: 0011 1011b, 3Bh bit allocation . . . . . . .60

Table 81. TypeBFraming register bit descriptions . . . . . .60

Table 82. RxControl1 register (address: 19h) reset value:

0111 0011b, 73h bit allocation . . . . . . . . . . . . .61

Table 83. RxControl1 register bit descriptions . . . . . . . . .61

Table 84. DecoderControl register (address: 1Ah) reset

value: 0000 1000b, 08h bit allocation . . . . . . .62

Table 85. DecoderControl register bit descriptions . . . . .62

Table 86. BitPhase register (address: 1Bh) reset value:

1010 1101b, ADh bit allocation . . . . . . . . . . . .62

Table 113. TimerControl register bit descriptions . . . . . . . 69

Table 114. TimerReload register (address: 2Ch) reset value:

0000 1010b, 0Ah bit allocation . . . . . . . . . . . . 69

Table 115. TimerReload register bit descriptions . . . . . . . 69

Table 116. IRQPinConfig register (address: 2Dh) reset value:

0000 0010b, 02h bit allocation . . . . . . . . . . . . 70

Table 117. IRQPinConfig register bit descriptions . . . . . . 70

Table 118. PreSet2E register (address: 2Eh) reset value:

xxxx xxxxb, xxh bit allocation . . . . . . . . . . . . . 70

Table 119. PreSet2F register (address: 2Fh) reset value:

xxxx xxxxb, xxh bit allocation . . . . . . . . . . . . . 70

Table 87. BitPhase register bit descriptions . . . . . . . . . .62

Table 88. RxThreshold register (address: 1Ch) reset value:

1111 1111b, FFh bit allocation . . . . . . . . . . . . .63

Table 120. Reserved registers (address: 31h, 32h, 33h, 34h,

35h, 36h, 37h) reset value: xxxx xxxxb, xxh bit

allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Table 89. RxThreshold register bit descriptions . . . . . . .63

Table 90. BPSKDemControl register (address: 1Dh) reset

value: 0001 1110b, 1Eh bit allocation . . . . . . .63

Table 91. BPSKDemControl register bit descriptions . . .63

Table 92. RxControl2 register (address: 1Eh) reset value:

0100 0001b, 41h bit allocation . . . . . . . . . . . . .64

Table 93. RxControl2 register bit descriptions . . . . . . . . .64

Table 94. ClockQControl register (address: 1Fh) reset

value: 000x xxxxb, xxh bit allocation . . . . . . . .64

Table 121. Reserved register (address: 39h) reset value:

xxxx xxxxb, xxh bit allocation . . . . . . . . . . . . . 71

Table 122. TestAnaSelect register (address: 3Ah) reset

value: 0000 0000b, 00h bit allocation . . . . . . . 71

Table 123. TestAnaSelect bit descriptions . . . . . . . . . . . . 71

Table 124. Reserved register (address: 3Bh) reset value:

xxxx xxxxb, xxh bit allocation . . . . . . . . . . . . . 72

Table 125. Reserved register (address: 3Ch) reset value:

xxxx xxxxb, xxh bit allocation . . . . . . . . . . . . . 72

Table 95. ClockQControl register bit descriptions . . . . . .64

Table 96. RxWait register (address: 21h) reset value: 0000

0101b, 06h bit allocation . . . . . . . . . . . . . . . . .65

Table 97. RxWait register bit descriptions . . . . . . . . . . . .65

Table 98. ChannelRedundancy register (address: 22h)

reset value: 0000 0011b, 03h bit allocation . . .65

Table 99. ChannelRedundancy bit descriptions . . . . . . .65

Table 100. CRCPresetLSB register (address: 23h) reset

value: 0101 0011b, 63h bit allocation . . . . . . .66

Table 101. CRCPresetLSB register bit descriptions . . . . .66

Table 102. CRCPresetMSB register (address: 24h) reset

value: 0101 0011b, 63h bit allocation . . . . . . .66

Table 126. TestDigiSelect register (address: 3Dh) reset

value: xxxx xxxxb, xxh bit allocation . . . . . . . . 72

Table 127. TestDigiSelect register bit descriptions . . . . . 72

Table 128. Reserved register (address: 3Eh, 3Fh) reset

value: xxxx xxxxb, xxh bit allocation . . . . . . . . 73

Table 129. MFRC531 commands overview . . . . . . . . . . . 73

Table 130. StartUp command 3Fh . . . . . . . . . . . . . . . . . . 75

Table 131. Idle command 00h . . . . . . . . . . . . . . . . . . . . . 75

Table 132. Transmit command 1Ah . . . . . . . . . . . . . . . . . 76

Table 133. Transmission of frames of more than

64 bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Table 134. Receive command 16h . . . . . . . . . . . . . . . . . 79

Table 135. Return values for bit-collision positions . . . . . 81

Table 103. CRCPresetMSB bit descriptions . . . . . . . . . . .66

continued >>

MFRC531

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Product data sheet

COMPANY PUBLIC

Rev. 3.6 — 27 February 2014

056636

112 of 117

MFRC531

NXP Semiconductors

Standard ISO/IEC 14443 A/B reader solution

Table 136. Communication error table . . . . . . . . . . . . . . .81

Table 137. Transceive command 1Eh . . . . . . . . . . . . . . .82

Table 138. Meaning of ModemState . . . . . . . . . . . . . . . . .82

Table 139. WriteE2 command 01h . . . . . . . . . . . . . . . . . .84

Table 140. ReadE2 command 03h . . . . . . . . . . . . . . . . . .86

Table 141. LoadConfig command 07h . . . . . . . . . . . . . . .86

Table 142. CalcCRC command 12h . . . . . . . . . . . . . . . . .87

Table 143. CRC coprocessor parameters . . . . . . . . . . . .87

Table 144. ErrorFlag register error flags overview . . . . . .88

Table 145. LoadKeyE2 command 0Bh . . . . . . . . . . . . . . .88

Table 146. LoadKey command 19h . . . . . . . . . . . . . . . . .88

Table 147. Authent1 command 0Ch . . . . . . . . . . . . . . . . .89

Table 148. Authent2 command 14h . . . . . . . . . . . . . . . . .89

Table 149. Limiting values. . . . . . . . . . . . . . . . . . . . . . . . .90

Table 150. Operating condition range . . . . . . . . . . . . . . . .90

Table 151. Current consumption . . . . . . . . . . . . . . . . . . . .91

Table 152. Standard input pin characteristics . . . . . . . . . .91

Table 153. Schmitt trigger input pin characteristics . . . . .91

Table 154. RSTPD input pin characteristics . . . . . . . . . . .92

Table 155. RX input capacitance and input voltage range 92

Table 156. Digital output pin characteristics . . . . . . . . . . .92

Table 157. Antenna driver output pin characteristics . . . .93

Table 158. Timing specification for separate read/write

strobe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93

Table 159. Common read/write strobe timing

specification . . . . . . . . . . . . . . . . . . . . . . . . . . .94

Table 160. Common read/write strobe timing

specification for EPP . . . . . . . . . . . . . . . . . . . .95

Table 161. SPI timing specification . . . . . . . . . . . . . . . . . .97

Table 162. Clock frequency . . . . . . . . . . . . . . . . . . . . . . .97

Table 163. EEPROM characteristics . . . . . . . . . . . . . . . .98

Table 164. Signal routed to pin MFOUT . . . . . . . . . . . . .101

Table 165. Analog test signal selection . . . . . . . . . . . . .103

Table 166. Digital test signal selection . . . . . . . . . . . . . .104

Table 167. Abbreviations and acronyms . . . . . . . . . . . . .107

Table 168. Revision history . . . . . . . . . . . . . . . . . . . . . . .108

MFRC531

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Product data sheet

COMPANY PUBLIC

Rev. 3.6 — 27 February 2014

056636

113 of 117

MFRC531

NXP Semiconductors

Standard ISO/IEC 14443 A/B reader solution

23. Figures

Fig 1. MFRC531 block diagram. . . . . . . . . . . . . . . . . . . .4

Fig 2. MFRC531 pin configuration. . . . . . . . . . . . . . . . . .5

Fig 3. Connection to microprocessor: separate read

and write strobes . . . . . . . . . . . . . . . . . . . . . . . . . .8

Fig 4. Connection to microprocessor: common read

and write strobes . . . . . . . . . . . . . . . . . . . . . . . . . .9

Fig 5. Connection to microprocessor: EPP common

read/write strobes and handshake. . . . . . . . . . . . .9

Fig 6. Connection to microprocessor: SPI . . . . . . . . . . .10

Fig 7. Key storage format . . . . . . . . . . . . . . . . . . . . . . .16

Fig 8. Timer module block diagram . . . . . . . . . . . . . . . .23

Fig 9. The StartUp procedure. . . . . . . . . . . . . . . . . . . . .27

Fig 10. Quartz clock connection . . . . . . . . . . . . . . . . . . .29

Fig 11. Receiver circuit block diagram. . . . . . . . . . . . . . .33

Fig 12. Automatic Q-clock calibration . . . . . . . . . . . . . . .34

Fig 13. Serial signal switch block diagram. . . . . . . . . . . .36

Fig 14. Crypto1 key handling block diagram . . . . . . . . . .40

Fig 15. Transmitting bit oriented frames . . . . . . . . . . . . .77

Fig 16. Timing for transmitting byte oriented frames . . . .78

Fig 17. Timing for transmitting bit oriented frames. . . . . .78

Fig 18. Card communication state diagram . . . . . . . . . . .83

Fig 19. EEPROM programming timing diagram. . . . . . . .85

Fig 20. Separate read/write strobe timing diagram . . . . .94

Fig 21. Common read/write strobe timing diagram . . . . .95

Fig 22. Timing diagram for common read/write strobe;

EPP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96

Fig 23. Timing diagram for SPI . . . . . . . . . . . . . . . . . . . .97

Fig 24. Application example circuit diagram: directly

matched antenna. . . . . . . . . . . . . . . . . . . . . . . . .98

Fig 25. TX control signals . . . . . . . . . . . . . . . . . . . . . . .102

Fig 26. RX control signals . . . . . . . . . . . . . . . . . . . . . . .103

Fig 27. ISO/IEC 14443 A receiving path Q-clock. . . . . .105

Fig 28. Package outline SOT287-1 . . . . . . . . . . . . . . . .106

MFRC531

All information provided in this document is subject to legal disclaimers.

Product data sheet

COMPANY PUBLIC

Rev. 3.6 — 27 February 2014

056636

114 of 117

MFRC531

NXP Semiconductors

Standard ISO/IEC 14443 A/B reader solution

24. Contents

1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

9.5

9.5.1

Timer unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Timer unit implementation . . . . . . . . . . . . . . . 23

Timer unit block diagram . . . . . . . . . . . . . . . . 23

Controlling the timer unit . . . . . . . . . . . . . . . . 23

Timer unit clock and period . . . . . . . . . . . . . . 24

Timer unit status. . . . . . . . . . . . . . . . . . . . . . . 24

Using the timer unit functions. . . . . . . . . . . . . 25

Time-out and WatchDog counters . . . . . . . . . 25

Stopwatch . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Programmable one shot timer and

periodic trigger . . . . . . . . . . . . . . . . . . . . . . . . 25

Timer unit registers . . . . . . . . . . . . . . . . . . . . 25

Power reduction modes . . . . . . . . . . . . . . . . . 26

Hard power-down. . . . . . . . . . . . . . . . . . . . . . 26

Soft power-down mode . . . . . . . . . . . . . . . . . 26

Standby mode . . . . . . . . . . . . . . . . . . . . . . . . 27

Automatic receiver power-down. . . . . . . . . . . 27

StartUp phase . . . . . . . . . . . . . . . . . . . . . . . . 27

Hard power-down phase . . . . . . . . . . . . . . . . 27

Reset phase. . . . . . . . . . . . . . . . . . . . . . . . . . 28

Initialization phase . . . . . . . . . . . . . . . . . . . . . 28

Initializing the parallel interface type . . . . . . . 28

Oscillator circuit . . . . . . . . . . . . . . . . . . . . . . . 29

Transmitter pins TX1 and TX2 . . . . . . . . . . . . 29

Configuring pins TX1 and TX2. . . . . . . . . . . . 29

Antenna operating distance versus power

2

General description. . . . . . . . . . . . . . . . . . . . . . 1

Features and benefits . . . . . . . . . . . . . . . . . . . . 2

General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Quick reference data . . . . . . . . . . . . . . . . . . . . . 3

Ordering information. . . . . . . . . . . . . . . . . . . . . 3

Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Pinning information. . . . . . . . . . . . . . . . . . . . . . 5

Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 5

9.5.1.1

9.5.1.2

9.5.1.3

9.5.1.4

9.5.2

9.5.2.1

9.5.2.2

9.5.2.3

3

3.1

4

5

6

7

8

8.1

9.5.3

9.6

9

9.1

9.1.1

Functional description . . . . . . . . . . . . . . . . . . . 7

Digital interface. . . . . . . . . . . . . . . . . . . . . . . . . 7

Overview of supported microprocessor

interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Automatic microprocessor interface detection . 7

Connection to different microprocessor types . 8

Separate read and write strobe . . . . . . . . . . . . 8

Common read and write strobe . . . . . . . . . . . . 9

Common read and write strobe: EPP with

9.6.1

9.6.2

9.6.3

9.6.4

9.7

9.7.1

9.7.2

9.7.3

9.7.4

9.8

9.1.2

9.1.3

9.1.3.1

9.1.3.2

9.1.3.3

handshake . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Serial Peripheral Interface . . . . . . . . . . . . . . . . 9

SPI read data . . . . . . . . . . . . . . . . . . . . . . . . . 10

SPI write data . . . . . . . . . . . . . . . . . . . . . . . . . 11

Memory organization of the EEPROM . . . . . . 12

Product information field (read only). . . . . . . . 13

Register initialization files (read/write) . . . . . . 13

StartUp register initialization file (read/write) . 14

Factory default StartUp register

initialization file . . . . . . . . . . . . . . . . . . . . . . . . 14

Register initialization file (read/write) . . . . . . . 16

Crypto1 keys (write only) . . . . . . . . . . . . . . . . 16

Key format . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Storage of keys in the EEPROM . . . . . . . . . . 17

FIFO buffer . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Accessing the FIFO buffer . . . . . . . . . . . . . . . 17

Access rules . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Controlling the FIFO buffer . . . . . . . . . . . . . . . 18

FIFO buffer status information . . . . . . . . . . . . 18

FIFO buffer registers and flags. . . . . . . . . . . . 19

Interrupt request system. . . . . . . . . . . . . . . . . 19

Interrupt sources overview . . . . . . . . . . . . . . . 19

Interrupt request handling. . . . . . . . . . . . . . . . 20

Controlling interrupts and getting their status . 20

Accessing the interrupt registers . . . . . . . . . . 20

Configuration of pin IRQ. . . . . . . . . . . . . . . . . 21

Register overview interrupt request system . . 21

9.1.4

9.1.4.1

9.1.4.2

9.2

9.2.1

9.2.2

9.9

9.9.1

9.9.2

consumption. . . . . . . . . . . . . . . . . . . . . . . . . . 30

Antenna driver output source resistance . . . . 30

Source resistance table . . . . . . . . . . . . . . . . . 31

Calculating the relative source resistance . . . 32

Calculating the effective source resistance . . 32

Pulse width. . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Receiver circuitry . . . . . . . . . . . . . . . . . . . . . . 32

Receiver circuit block diagram. . . . . . . . . . . . 33

Receiver operation. . . . . . . . . . . . . . . . . . . . . 33

9.9.3

9.2.2.1

9.2.2.2

9.9.3.1

9.9.3.2

9.9.3.3

9.9.4

9.10

9.10.1

9.10.2

9.2.2.3

9.2.3

9.2.3.1

9.2.3.2

9.3

9.3.1

9.3.1.1

9.3.2

9.3.3

9.3.4

9.4

9.4.1

9.4.2

9.4.2.1

9.4.2.2

9.4.3

9.4.4

9.10.2.1 Automatic Q-clock calibration . . . . . . . . . . . . 33

9.10.2.2 Amplifier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

9.10.2.3 Correlation circuitry . . . . . . . . . . . . . . . . . . . . 35

9.10.2.4 Evaluation and digitizer circuitry . . . . . . . . . . 35

9.11

9.11.1

9.11.2

9.11.2.1 Active antenna concept . . . . . . . . . . . . . . . . . 37

9.11.2.2 Driving both RF parts . . . . . . . . . . . . . . . . . . . 38

9.12

9.13

9.14

Serial signal switch . . . . . . . . . . . . . . . . . . . . 35

Serial signal switch block diagram. . . . . . . . . 36

Serial signal switch registers . . . . . . . . . . . . . 36

MIFARE higher baud rates. . . . . . . . . . . . . . . 38

ISO/IEC 14443 B communication scheme. . . 39

MIFARE authentication and Crypto1 . . . . . . . 40

Crypto1 key handling . . . . . . . . . . . . . . . . . . . 40

9.14.1

continued >>

MFRC531

All information provided in this document is subject to legal disclaimers.

Product data sheet

COMPANY PUBLIC

Rev. 3.6 — 27 February 2014

056636

115 of 117

MFRC531

NXP Semiconductors

Standard ISO/IEC 14443 A/B reader solution

9.14.2

Authentication procedure . . . . . . . . . . . . . . . . 41

10.5.5.4 CRCPresetLSB register. . . . . . . . . . . . . . . . . 66

10.5.5.5 CRCPresetMSB register . . . . . . . . . . . . . . . . 66

10.5.5.6 PreSet25 register. . . . . . . . . . . . . . . . . . . . . . 66

10.5.5.7 MFOUTSelect register . . . . . . . . . . . . . . . . . . 67

10.5.5.8 PreSet27 register. . . . . . . . . . . . . . . . . . . . . . 67

10

10.1

10.1.1

10.1.2

10.1.3

10.2

10.3

10.4

10.5

10.5.1

MFRC531 registers . . . . . . . . . . . . . . . . . . . . . 41

Register addressing modes . . . . . . . . . . . . . . 41

Page registers . . . . . . . . . . . . . . . . . . . . . . . . 41

Dedicated address bus. . . . . . . . . . . . . . . . . . 41

Multiplexed address bus. . . . . . . . . . . . . . . . . 41

Register bit behavior. . . . . . . . . . . . . . . . . . . . 42

Register overview. . . . . . . . . . . . . . . . . . . . . . 43

MFRC531 register flags overview. . . . . . . . . . 45

Register descriptions . . . . . . . . . . . . . . . . . . . 48

Page 0: Command and status . . . . . . . . . . . . 48

10.5.6

Page 5: FIFO, timer and IRQ

pin configuration. . . . . . . . . . . . . . . . . . . . . . . 68

10.5.6.1 Page register . . . . . . . . . . . . . . . . . . . . . . . . . 68

10.5.6.2 FIFOLevel register . . . . . . . . . . . . . . . . . . . . . 68

10.5.6.3 TimerClock register . . . . . . . . . . . . . . . . . . . . 68

10.5.6.4 TimerControl register . . . . . . . . . . . . . . . . . . . 69

10.5.6.5 TimerReload register . . . . . . . . . . . . . . . . . . . 69

10.5.6.6 IRQPinConfig register . . . . . . . . . . . . . . . . . . 70

10.5.6.7 PreSet2E register. . . . . . . . . . . . . . . . . . . . . . 70

10.5.6.8 PreSet2F register. . . . . . . . . . . . . . . . . . . . . . 70

10.5.1.1 Page register . . . . . . . . . . . . . . . . . . . . . . . . . 48

10.5.1.2 Command register . . . . . . . . . . . . . . . . . . . . . 48

10.5.1.3 FIFOData register. . . . . . . . . . . . . . . . . . . . . . 49

10.5.1.4 PrimaryStatus register . . . . . . . . . . . . . . . . . . 49

10.5.1.5 FIFOLength register . . . . . . . . . . . . . . . . . . . . 50

10.5.1.6 SecondaryStatus register . . . . . . . . . . . . . . . . 51

10.5.1.7 InterruptEn register. . . . . . . . . . . . . . . . . . . . . 51

10.5.1.8 InterruptRq register. . . . . . . . . . . . . . . . . . . . . 52

10.5.7

Page 6: reserved . . . . . . . . . . . . . . . . . . . . . . 70

10.5.7.1 Page register . . . . . . . . . . . . . . . . . . . . . . . . . 70

10.5.7.2 Reserved registers 31h, 32h, 33h, 34h,

35h, 36h and 37h. . . . . . . . . . . . . . . . . . . . . . 70

10.5.8

Page 7: Test control . . . . . . . . . . . . . . . . . . . . 71

10.5.2

Page 1: Control and status . . . . . . . . . . . . . . . 53

10.5.8.1 Page register . . . . . . . . . . . . . . . . . . . . . . . . . 71

10.5.8.2 Reserved register 39h . . . . . . . . . . . . . . . . . . 71

10.5.8.3 TestAnaSelect register. . . . . . . . . . . . . . . . . . 71

10.5.8.4 Reserved register 3Bh . . . . . . . . . . . . . . . . . . 72

10.5.8.5 Reserved register 3Ch. . . . . . . . . . . . . . . . . . 72

10.5.8.6 TestDigiSelect register . . . . . . . . . . . . . . . . . . 72

10.5.8.7 Reserved registers 3Eh, 3Fh . . . . . . . . . . . . . 73

10.5.2.1 Page register . . . . . . . . . . . . . . . . . . . . . . . . . 53

10.5.2.2 Control register. . . . . . . . . . . . . . . . . . . . . . . . 53

10.5.2.3 ErrorFlag register . . . . . . . . . . . . . . . . . . . . . . 53

10.5.2.4 CollPos register . . . . . . . . . . . . . . . . . . . . . . . 54

10.5.2.5 TimerValue register. . . . . . . . . . . . . . . . . . . . . 55

10.5.2.6 CRCResultLSB register . . . . . . . . . . . . . . . . . 55

10.5.2.7 CRCResultMSB register. . . . . . . . . . . . . . . . . 55

10.5.2.8 BitFraming register . . . . . . . . . . . . . . . . . . . . . 56

11

11.1

11.1.1

11.1.2

11.1.3

11.2

MFRC531 command set . . . . . . . . . . . . . . . . . 73

MFRC531 command overview. . . . . . . . . . . . 73

Basic states . . . . . . . . . . . . . . . . . . . . . . . . . . 75

StartUp command 3Fh. . . . . . . . . . . . . . . . . . 75

Idle command 00h . . . . . . . . . . . . . . . . . . . . . 75

Commands for ISO/IEC 14443 A card

10.5.3

Page 2: Transmitter and control . . . . . . . . . . . 57

10.5.3.1 Page register . . . . . . . . . . . . . . . . . . . . . . . . . 57

10.5.3.2 TxControl register. . . . . . . . . . . . . . . . . . . . . . 57

10.5.3.3 CwConductance register . . . . . . . . . . . . . . . . 58

10.5.3.4 ModConductance register. . . . . . . . . . . . . . . . 58

10.5.3.5 CoderControl register . . . . . . . . . . . . . . . . . . . 59

10.5.3.6 ModWidth register. . . . . . . . . . . . . . . . . . . . . . 59

10.5.3.7 PreSet16 register . . . . . . . . . . . . . . . . . . . . . . 59

10.5.3.8 TypeBFraming . . . . . . . . . . . . . . . . . . . . . . . . 60

communication. . . . . . . . . . . . . . . . . . . . . . . . 76

Transmit command 1Ah. . . . . . . . . . . . . . . . . 76

11.2.1

11.2.1.1 Using the Transmit command . . . . . . . . . . . . 76

11.2.1.2 RF channel redundancy and framing. . . . . . . 77

11.2.1.3 Transmission of bit oriented frames. . . . . . . . 77

11.2.1.4 Transmission of frames with more than

10.5.4

Page 3: Receiver and decoder control . . . . . . 61

10.5.4.1 Page register . . . . . . . . . . . . . . . . . . . . . . . . . 61

10.5.4.2 RxControl1 register. . . . . . . . . . . . . . . . . . . . . 61

10.5.4.3 DecoderControl register . . . . . . . . . . . . . . . . . 62

10.5.4.4 BitPhase register . . . . . . . . . . . . . . . . . . . . . . 62

10.5.4.5 RxThreshold register . . . . . . . . . . . . . . . . . . . 63

10.5.4.6 BPSKDemControl. . . . . . . . . . . . . . . . . . . . . . 63

10.5.4.7 RxControl2 register. . . . . . . . . . . . . . . . . . . . . 64

10.5.4.8 ClockQControl register . . . . . . . . . . . . . . . . . . 64

64 bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

11.2.2

Receive command 16h . . . . . . . . . . . . . . . . . 79

11.2.2.1 Using the Receive command. . . . . . . . . . . . . 79

11.2.2.2 RF channel redundancy and framing. . . . . . . 79

11.2.2.3 Collision detection . . . . . . . . . . . . . . . . . . . . . 80

11.2.2.4 Receiving bit oriented frames . . . . . . . . . . . . 81

11.2.2.5 Communication errors . . . . . . . . . . . . . . . . . . 81

10.5.5

Page 4: RF Timing and channel redundancy . 65

11.2.3

11.2.4

11.2.5

11.3

Transceive command 1Eh . . . . . . . . . . . . . . . 82

States of the card communication . . . . . . . . . 82

Card communication state diagram . . . . . . . . 83

EEPROM commands. . . . . . . . . . . . . . . . . . . 84

10.5.5.1 Page register . . . . . . . . . . . . . . . . . . . . . . . . . 65

10.5.5.2 RxWait register . . . . . . . . . . . . . . . . . . . . . . . . 65

10.5.5.3 ChannelRedundancy register . . . . . . . . . . . . . 65

continued >>

MFRC531

All information provided in this document is subject to legal disclaimers.

Product data sheet

COMPANY PUBLIC

Rev. 3.6 — 27 February 2014

056636

116 of 117

MFRC531

NXP Semiconductors

Standard ISO/IEC 14443 A/B reader solution

11.3.1

WriteE2 command 01h . . . . . . . . . . . . . . . . . . 84

15.2.3

15.2.4

Digital test signals . . . . . . . . . . . . . . . . . . . . 104

Examples of ISO/IEC 14443 A analog

and digital test signals . . . . . . . . . . . . . . . . . 104

11.3.1.1 Programming process . . . . . . . . . . . . . . . . . . 84

11.3.1.2 Timing diagram. . . . . . . . . . . . . . . . . . . . . . . . 85

11.3.1.3 WriteE2 command error flags. . . . . . . . . . . . . 85

16

17

18

19

Package outline. . . . . . . . . . . . . . . . . . . . . . . 106

Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . 107

References. . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Revision history . . . . . . . . . . . . . . . . . . . . . . 108

11.3.2

ReadE2 command 03h. . . . . . . . . . . . . . . . . . 86

11.3.2.1 ReadE2 command error flags. . . . . . . . . . . . . 86

11.4

11.4.1

Diverse commands. . . . . . . . . . . . . . . . . . . . . 86

LoadConfig command 07h . . . . . . . . . . . . . . . 86

20

Legal information . . . . . . . . . . . . . . . . . . . . . 109

Data sheet status . . . . . . . . . . . . . . . . . . . . . 109

Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . 109

Licenses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . 110

11.4.1.1 Register assignment. . . . . . . . . . . . . . . . . . . . 86

11.4.1.2 Relevant LoadConfig command error flags . . 87

20.1

20.2

20.3

20.4

20.5

11.4.2

CalcCRC command 12h. . . . . . . . . . . . . . . . . 87

11.4.2.1 CRC coprocessor settings . . . . . . . . . . . . . . . 87

11.4.2.2 CRC coprocessor status flags . . . . . . . . . . . . 87

11.5

11.6

11.6.1

Error handling during command execution. . . 88

MIFARE security commands . . . . . . . . . . . . . 88

LoadKeyE2 command 0Bh. . . . . . . . . . . . . . . 88

21

22

23

24

Contact information . . . . . . . . . . . . . . . . . . . . 110

Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

11.6.1.1 Relevant LoadKeyE2 command error flags . . 88

11.6.2 LoadKey command 19h . . . . . . . . . . . . . . . . . 88

11.6.2.1 Relevant LoadKey command error flags . . . . 89

11.6.3

11.6.4

Authent1 command 0Ch. . . . . . . . . . . . . . . . . 89

Authent2 command 14h . . . . . . . . . . . . . . . . . 89

11.6.4.1 Authent2 command effects. . . . . . . . . . . . . . . 90

12

Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . 90

13

13.1

13.2

13.3

13.3.1

13.3.2

13.3.3

13.4

13.4.1

13.4.2

13.4.3

13.4.4

13.4.5

Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . 90

Operating condition range . . . . . . . . . . . . . . . 90

Current consumption . . . . . . . . . . . . . . . . . . . 91

Pin characteristics . . . . . . . . . . . . . . . . . . . . . 91

Input pin characteristics . . . . . . . . . . . . . . . . . 91

Digital output pin characteristics. . . . . . . . . . . 92

Antenna driver output pin characteristics . . . . 92

AC electrical characteristics . . . . . . . . . . . . . . 93

Separate read/write strobe bus timing . . . . . . 93

Common read/write strobe bus timing . . . . . . 94

EPP bus timing. . . . . . . . . . . . . . . . . . . . . . . . 95

SPI timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Clock frequency . . . . . . . . . . . . . . . . . . . . . . . 97

14

EEPROM characteristics. . . . . . . . . . . . . . . . . 98

15

15.1

15.1.1

15.1.2

Application information. . . . . . . . . . . . . . . . . . 98

Typical application . . . . . . . . . . . . . . . . . . . . . 98

Circuit diagram . . . . . . . . . . . . . . . . . . . . . . . . 98

Circuit description. . . . . . . . . . . . . . . . . . . . . . 99

15.1.2.1 EMC low-pass filter. . . . . . . . . . . . . . . . . . . . . 99

15.1.2.2 Antenna matching. . . . . . . . . . . . . . . . . . . . . . 99

15.1.2.3 Receiver circuit. . . . . . . . . . . . . . . . . . . . . . . 100

15.1.2.4 Antenna coil . . . . . . . . . . . . . . . . . . . . . . . . . 100

15.2

15.2.1

Test signals. . . . . . . . . . . . . . . . . . . . . . . . . . 101

Measurements using the serial signal switch 101

15.2.1.1 TX control . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

15.2.1.2 RX control. . . . . . . . . . . . . . . . . . . . . . . . . . . 102

15.2.2

Analog test signals . . . . . . . . . . . . . . . . . . . . 103

Please be aware that important notices concerning this document and the product(s)

described herein, have been included in section ‘Legal information’.

For more information, please visit: http://www.nxp.com

For sales office addresses, please send an email to: salesaddresses@nxp.com

Date of release: 27 February 2014

056636


型号：	MFRC53101T/0FE,112
厂家：	NXP
描述：	MFRC531 - Standard ISO/IEC 14443 A/B reader solution SOP 32-Pin 电信光电二极管电信集成电路
文件：	总117页 (文件大小：739K)
中文：	中文翻译
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MFRC53101T/0FE,112 [NXP]

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