QT60645B_技术文档

LQ

QT60325B, QT60485B, QT60645B

32, 48, 64 KEY QMatrix^™KEYPANEL

S

ENSOR IC

S

ꢀ Advanced second generation QMatrix controllers

ꢀ Up to 32, 48 or 64 touch keys through any dielectric

ꢀ Panel thicknesses to 5 cm or more

34

44 43 42 41 40 39 38 37 36 35

MOSI

MISO

SCLK

RST

Vdd

1

2

3

4

5

6

7

8

9

33

CZ2

YS0

YS1

YS2

Aref

AGnd

AVdd

YC7

YC6

YC5

YC4

ꢀ 100% autocal for life - no adjustments required

ꢀ Keys individually adjustable for sensitivity, response time,

and many other critical parameters

32

31

30

29

28

27

26

25

24

23

QT60325B

QT60485B

QT60645B

ꢀ Mix and match key sizes & shapes in one panel

ꢀ Passive matrix - no components at the keys

ꢀ Moisture suppression capable

Vss

XTO

XTI

TQFP-44

X0

ꢀ AKS™ - Adjacent Key Suppression feature

ꢀ Synchronous noise suppression

ꢀ Sleep mode with wake pin

X1

10

11

X2WS

13 14 15 16 17 18 19 20 21 22

12

ꢀ SPI Slave or Master/Slave interface to a host controller

ꢀ Low overhead communications protocol

ꢀ 44-pin TQFP package

APPLICATIONS

ꢀ Security keypanels

ꢀ Industrial keyboards

ꢀ Appliance controls

ꢀ Outdoor keypads

ꢀ ATM machines

ꢀ Touch-screens

ꢀ Automotive panels

ꢀ Machine tools

The QT60325B, QT60485B, and QT60645B digital charge-transfer (“QT”) QMatrix™ ICs are designed to detect human touch on

up to 32, 48, or 64 keys respectively using a scanned, passive X-Y matrix. It will project the keys through almost any dielectric, e.g.

glass, plastic, stone, ceramic, and even wood, up to thicknesses of 5 cm or more. The touch areas are defined as simple 2-part

interdigitated electrodes of conductive material, like copper or screened silver or carbon deposited on the rear of a control panel.

Key sizes, shapes and placement are almost entirely arbitrary; sizes and shapes of keys can be mixed within a single panel of

keys and can vary by a factor of 20:1 in surface area. The sensitivity of each key can be set individually via simple functions over

the SPI port, for example via Quantum’s QmBtn program. Key setups are stored in an onboard eeprom and do not need to be

reloaded with each power-up.

These ICs are designed specifically for appliances, electronic kiosks, security panels, portable instruments, machine tools, or

similar products that are subject to environmental influences or even vandalism. They permit the construction of 100% sealed,

watertight control panels that are immune to humidity, temperature, dirt accumulation, or the physical deterioration of the panel

surface from abrasion, chemicals, or abuse. To this end the devices contain Quantum-pioneered adaptive self-calibration, drift

compensation, and digital filtering algorithms that make the sensing function robust and survivable. The devices use short dwell

times and Quantum’s patent-pending AKS™ feature to permit operation in wet environments.

The parts use a passive key matrix, dramatically reducing cost over older technologies that require an ASIC for every key. The

key-matrix can be made of standard flex material (e.g. Silver on PET plastic) or ordinary PCB material to save cost.

External circuitry consists of an opamp, R2R ladder-DAC network, a common PLD, a FET switch, and a small number of resistors

and capacitors which can fit into a footprint of roughly 8 sq. cm (1.5 sq. in). Control and data transfer is via a SPI port which can

be configured in either a Slave or Master/Slave mode.

QT60xx5B ICs make use of an important new variant of charge-transfer sensing, transverse charge-transfer, in a matrix format

that minimizes the number of required scan lines to provide a high economy of scale.

The B version is identical to the earlier QT60xx5 parts in all respects except that the device exhibits lower signal noise.

QT60xx5B replaces QT60xx5 parts with no circuit changes. After 2003, QT60xx5 devices will no longer be available.

AVAILABLE OPTIONS

T_A

TQFP

-40⁰C to +105⁰C

QT60325B-AS

QT60485B-AS

QT60645B-AS

lQ

Pat Pend. R1.06/0403

Contents

1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2

3

4

5

6

7

0x32 - Reference Value

0x33 - R2R Offset

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4

5

6

7

8

9

1.1 Field Flows

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0x34 - Cz State

1.2 Circuit Model

0x35 - Detection Integrator Counts

1.3 Matrix Configuration

. . . . . . . . . . . . . . . . . . . . . . 22

. . . . . . . . . . . . . . . . . . . . . . . . . . . 22

. . . . . . . . . . . . . . . . . . . . . . . . . 22

. . . . . . . . . . . . . . . . . . . . . . . 22

. . . . . . . . . . . . . . . . . . . . . . . . . 22

. . . . . . . . . . . . . . . . . . . . . . 22

. . . . . . . . . . . . . . . . . . . . . . . . . . 22

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0x36 - Eeprom Checksum

1.4 Communications

0x37 - General Device Status

2 Signal Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.1 Negative Threshold

<sp> 0x20 - Signal Levels for Group

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

!

0x21 - Delta Signals for Group

2.2 Positive Threshold

"

0x22 - Reference Levels for Group

2.3 Hysteresis

#

$

%

e

k

K

0x23 - R2R Offset for Group

2.4 Drift Compensation

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0x24 - Charge Cancellation for Group

2.5 Detection Recalibration Delay

. . . . . . . . . . . . . . . . . . . . 22

. . . . . . . . . . . . . . . . . 22

. . . . . . . . . . . . . . . . . . . . . 23

. . . . . . . . . . . . . . . . . . . . 23

. . . . . . . . . . . . . . . . . . . 24

. . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0x25 - Detect Integrator Counts for Group

2.6 Detect Integrator (‘DI’)

0x65 - Error Code for Selected Key

0x6B - Reporting of First Touched Key

0x4B - Key Touch Reporting for Group

2.7 Positive Recalibration Delay

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.8 Reference Guardbanding

2.9 Adjacent Key Suppression (AKS™)

. . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.4 Setup Commands

^A 0x01 - Negative Detect Threshold

2.10 Full Recalibration

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

. . . . . . . . . . . . . . . . . . . . . . . 24

2.11 Boundary Error Reporting

2.12 Device Status & Reporting

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3 Circuit Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

^B 0x02 - Positive Detect Threshold

^C 0x03 - Negative Threshold Hysteresis

^D 0x04 - Positive Threshold Hysteresis

^E 0x05 - Dwell Time in Machine Cycles

^G 0x07 - Burst Spacing

. . . . . . . . . . . . . . . . . . . . 25

. . . . . . . . . . . . . . . . . . . . . 25

3.1 Part Differences

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.2 Matrix Scan Sequence

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3.3 Signal Path

^H 0x08 - Negative Drift Compensation Rate

. . . . . . . . . . . . . . . . . . 26

. . . . . . . . . . . . . . . . . . . 26

. . . . . . . . . . . . . . . . . . . . . . . . . 26

. . . . . . . . . . . . . . . . . . . . . 26

. . . . . . . . . . . . . . . . . . . . . . . 27

3.4 'X' Electrode Drives

3.4.1 RFI From X Lines

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

^I 0x09 - Positive Drift Compensation Rate

^J 0x0A - Detect Integrator Limit

3.4.2 Noise Coupling Into X lines

. . . . . . . . . . . . . . . . . . . . . . . . . . 12

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

^K 0x0B - Positive Recalibration Delay

3.5 'Y' Gate Drives

3.5.1 RFI From Y Lines

^L 0x0C - Negative Recalibration Delay

^M 0x0D - Intra-Burst Pulse Spacing

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.5.2 Noise Coupling Into Y Lines

3.6 Burst Length & Sensitivity

3.7 Intra-Burst Spacing

. . . . . . . . . . . . . . . . . . . . . . . . . . 12

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

^N 0x0E - Positive Reference Error Band

^O 0x0F - Negative Reference Error Band

^P 0x10 - Adjacent Key Suppression (‘AKS’)

5.5 Supervisory / System Functions

. . . . . . . . . . . . . . . . . . . . 27

. . . . . . . . . . . . . . . . . . . 27

. . . . . . . . . . . . . . . . . . 27

3.8 Burst Spacing

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

. . . . . . . . . . . . . . . . . . . . . . . . 28

. . . . . . . . . . . . . . . . . . . . . . . . . . . 28

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

3.9 PLD Circuit and Charge Sampler

3.10 Opamps

. . . . . . . . . . . . . . . . . . . . . . . 13

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

6

D

L

b

l

0x36 - Eeprom Checksum

0x44 - DAC Test

3.11 Sample Capacitors

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

0x4C - Lock Reference Levels

. . . . . . . . . . . . . . . . . . . . . . . . . 28

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

3.12 R2R Resistor Ladder

0x62 - Recalibrate Keys

3.13 Water Film Suppression

3.14 Reset Input

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

0x6C - Return Last Command Character

. . . . . . . . . . . . . . . . . . . 28

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

r

0x72 - Reset Device

3.15 Oscillator

V

W

Z

0x56 - Return Part Version

. . . . . . . . . . . . . . . . . . . . . . . . . . . 29

. . . . . . . . . . . . . . . . . . . . . . . . . 29

3.16 Startup / Calibration Times

3.17 Sleep_Wake / Noise Sync

3.18 LED / Alert Output

. . . . . . . . . . . . . . . . . . . . . . . . . . 14

. . . . . . . . . . . . . . . . . . . . . . . . . . . 14

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

0x57 - Return Part Signature

0x5A - Enter Sleep

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

^Q 0x11 - Data Rate Selection

^R 0x12 - Oscilloscope Sync

^S 0x13 - Cs Clamp Polarity

. . . . . . . . . . . . . . . . . . . . . . . . . . 29

. . . . . . . . . . . . . . . . . . . . . . . . . . . 29

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

3.19 CSR Drive Polarity

3.20 Oscilloscope Sync

3.21 Power Supply and PCB Layout

. . . . . . . . . . . . . . . . . . . . . . . . 15

. . . . . . . . . . . . . . . . . . . . . . . . . . 16

4 Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

^T 0x14 - Boundary Eqn Constant C1, MSB

^U 0x15 - Boundary Eqn Constant C1, LSB

^V 0x16 - Boundary Equation Constant C2

^W 0x17 - Noise Sync

. . . . . . . . . . . . . . . . . . 30

. . . . . . . . . . . . . . . . . . . 30

3.22 ESD / Noise Considerations

4.1 Serial Port specifications

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4.2 Protocol Overview

5.6 Function Summary Table

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6 PLD Source Listing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.3 SPI Slave-Only Mode

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

5.7 Timing Limitations

4.4 SPI Master-Slave Mode

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4.5 Sensor Echo and Data Response

. . . . . . . . . . . . . . . . . . . . . . . 19

4.6 Eeprom Corruption

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

5 Commands & Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

5.1 Direction Commands

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

g

0x67 - Get Command

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

. . . . . . . . . . . . . . . . . . . . . . . . . . . 21

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

. . . . . . . . . . . . . . . . . . . . . . . . . . . 21

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

. . . . . . . . . . . . . . . . . . . . . . . . . . 21

p

0x70 - Put Command

5.2 Scope Commands

s

S

x

0x73 - Specific Key Scope

0x53 - All Keys Scope

0x78 - Row Keys Scope

y

0x79 - Column Keys Scope

5.3 Status Commands

0

0x30 - Signal for Single Key

1

0x31 - Delta Signal for Single Key

. . . . . . . . . . . . . . . . . . . . . . . 21

lQ

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www.qprox.com QT60xx5B / R1.06

©Quantum Research Group Ltd.

Table 1.1 Device Pin List

Name

Type Description

Master-Out / Slave In SPI line. In Master/Slave SPI mode is used for both communication directions.

In Slave SPI mode is the data input (in only).

Master-In / Slave Out SPI line. Not used in Master/Slave SPI mode.

In Slave mode outputs data to host (out only).

SPI Clock. In Master mode is an output; in Slave mode is an input

Reset input, active low reset

1

MOSI

I/O PP

2

MISO

I/O PP

3

SCK

RST

Vdd

Vss

XTO

XTI

I/O PP

I

4

5

Pwr

O

+5 supply

Ground

6

7

Oscillator drive output. Connect to resonator or crystal.

Oscillator drive input. Connect to resonator or crystal, or external clock source.

X0 Drive matrix scan / R2R DAC Ladder drive

X1 Drive matrix scan / R2R DAC Ladder drive

X2 Drive matrix scan / R2R DAC Ladder drive / Wake from Sleep / Sync to noise source

X3 Drive matrix scan / R2R DAC Ladder drive

X4 Drive matrix scan / R2R DAC Ladder drive

X5 Drive matrix scan / R2R DAC Ladder drive

X6 Drive matrix scan / R2R DAC Ladder drive

X summation / R2R DAC Ladder drive

+5 supply

8

I

9

X0

X1

O

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

O

X2WS

X3

X4

O

X5

X6

O

XS

O

Vdd

Vss

YC0

YC1

YC2

YC3

YC4

YC5

YC6

YC7

AVdd

AGnd

Aref

YS2

YS1

YS0

CZ2

CZ1

CSR

Ain

Pwr

O

Ground

Y 0 Line clamp control

O

Y 1 Line clamp control

Y 2 Line clamp control

O

Y 3 Line clamp control

Y 4 Line clamp control

O

Y 5 Line clamp control

Y 6 Line clamp control

O

Y 7 Line clamp control

+5 supply for analog sections

Pwr

O

Analog ground

Analog reference, connect to Vcc

Transfer switch control bit 2

Transfer switch control bit 1

Transfer switch control bit 0

O

Charge cancellation drive for CZ2 capacitor

Charge cancellation drive for CZ1 capacitor

Charge integrator reset line. Active high or active low (select polarity via Setups)

Analog input from amplifier

O

I

MS

I/O OD

Pwr

O

SPI Mode / Sync out. Connect via 10k resistor to Vcc or Gnd for mode. Scope sync yields Pulse.

+5 supply

Ground

Vdd

Vss

LED

DRDY

X7

Active low LED status drive / Activity indicator

Data ready output for Slave SPI mode; active low

X7 Drive matrix scan

O OD

O

YG

SS

O

IO OD

Y gate control to drive Y dwell timing circuit

Slave select for SPI direction control; active low

I/O: I = Input

O = Output

Pwr = Power pin

I/O = Bi-directional line

PP = Push Pull output drive

OD = Open drain output drive

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www.qprox.com QT60xx5B / R1.06

Figure 1-2 Sample Electrode Geometries

1 Overview

QMatrix devices are digital burst mode charge-transfer (QT)

sensors designed specifically for matrix geometry touch

controls; they include all signal processing functions

necessary to provide stable sensing under a wide variety of

changing conditions. Only a few external parts are required

for operation. The entire circuit can be built within 8 square

centimeters of PCB area.

PARALLEL LINES

SERPENTINE

SPIRAL

Figure 1-1 Field flow between X and Y elements

edge transitions of the X drive pulse. The charge emitted by

the X electrode is partly received onto the corresponding Y

electrode which is then processed. The parts use 8 'X'

edge-driven rows and 8 'Y' sense columns to permit up to 64

keys. Keys are typically formed from interleaved conductive

traces on a substrate like a flex circuit or PCB (Figure 1-2).

overlying panel

X

Y

The charge flows are absorbed by the touch of a human

finger (Figure 1-3) resulting in a decrease in coupling from X

to Y. Thus, received signals decrease or go negative with

respect to the reference level during a touch.

element

Water films cause the coupled fields to increase slightly,

making water films easy to distinguish from touch.

QMatrix devices include charge cancellation methods which

allow for a wide range of key sizes and shapes to be mixed

together in a single touch panel. These features permit the

construction of entirely new classes of keypads never before

contemplated, such as touch-sliders, back-illuminated keys,

and complex warped panel shapes, all at very low cost.

1.2 Circuit Model

An electrical circuit model is shown in Figure 1-5. The

coupling capacitance between X and Y electrodes is

represented by Cx. While the reset switch is open, a sample

switch is gated so that it transfers charge flows only from the

rising edge of X into a charge integrator. On the falling edge

of X, the switch connects the Y line to ground to allow the

charge across Cx to neutralize to zero. The voltage change

on the output of the charge integrator after each X edge is

quite small, on the order of a few tens of millivolts. Changes

due to touch are typically under 0.1% of total integrator

voltage. The X pulse can be

The devices use an SPI interface running at up to 1.5MHz to

allow key data to be extracted and to permit individual key

parameter setup. The interface protocol uses simple single

byte commands and responds with single byte responses in

most cases. The command structure is designed to minimize

the amount of data traffic while maximizing the amount of

information conveyed.

repeated in a burst of up to 64

pulses to increase the change in

integrator output voltage due to

touch during an acquire (Section

3.6) to increase gain.

Figure 1-3 Field Flows When Touched

In addition to normal operating

and setup functions the device

can also report back actual

signal strengths and error codes.

QmBtn software for the PC can

be used to program the IC as

well as read back key status and

signal levels in real time.

The charge detector is an opamp

configured as an integrator with a

reset switch; this creates a virtual

ground input, making the Y lines

appear low impedance when the

sample switch is closed. This

configuration effectively

eliminates cross-coupling among

Y lines while greatly lowering

QMatrix parts employ transverse

charge-transfer ('QT') sensing, a

new technology that senses

changes in the charge forced

across an electrode by a digital

edge.

overlying panel

X

Y

element

susceptibility to EMI. The circuit

is also highly immune to

The parts are electrically

identical with the exception of the

number of keys which may be

sensed.

capacitive loading on the Y lines,

since stray C from Y to ground

appears merely as a small

parallel capacitance across a

Figure 1-4 Fields With a Conductive Film

virtual ground.

1.1 Field Flows

The circuit uses an 8-bit ADC,

with a subranging structure to

effectively deliver a 14-bit total

conversion 'space' (see Figure

1-6 and Section 3.3). In this way

the circuit can tolerate very large

Figure 1-1 shows how charge is

transferred across an electrode

set to permeate the overlying

panel material; this charge flow

exhibits a high dQ/dt during the

lQ

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www.qprox.com QT60xx5B / R1.06

Short sample gate dwell times after the X

edges will limit the effect of moisture

spreading from key to key by taking

advantage of the RC filter-like nature of

continuous films; a short dwell time will limit

the time that the charge has to travel

through the impedance of the film (Section

3.13). This effect is independent of the

frequency of burst repetition, intra-burst

pulse spacing, or X drive pulse width.

Figure 1-5 QT60xx5B Basic Circuit Model

Sample

switch (1 of 8)

X drive

(1 of 8)

switch (1 of 8)

Y line

(1 of 8)

0

Cx

0

Cancellation

(1 of 8)

Xn

switches

1

X

Y

X

Reset switch

electrode

0

Cz1

1

Burst mode operation permits reduced

power consumption and reduces RF

emissions, while permitting excellent

response time.

Cs

Cz2

Ca

Cha rge

In te grator

Xn

To 60xxx ADC

Amp

Am p

Reset

switch

1.3 Matrix Configuration

S

a

m

p

lele

The matrix scanning configuration is shown

in Figure 1-5. The ‘X’ drives are sequentially

pulsed in groupings of bursts; an 8:1 analog

mux acts as the sample switch for all ‘Y’

lines. At the intersection of each ‘X’ and ‘Y’

line in the matrix itself, where a key is

s

w

it

i

c

tc

h

FFrroomm 6600xxxxxx

8-bit

Offset DAC

Offset Control

Amp

out

V

out

ou t

0

absolute signals yet still respond to very small signal

changes. Subranging is provided by two offset mechanisms

which can be thought of as 'coarse' and 'fine' offsets.

desired, should be an interdigitated electrode set similar to

those shown in Figure 1-2. The outermost electrode or the

key border should always be connected to an ‘X’ drive;

flooding the area around keys with X fill to a width of up to

10mm can help in suppressing moisture films further.

The 'coarse' method uses one or two switched Cz capacitors

to subtract charge from the charge integrator to create up to

two step offsets, to bring the analog signal back to a more

reasonable level. This action occurs during the course of the

burst.

Although it is referred to as a ‘matrix’, there is no restriction

on where individual keys can be located. The term ‘matrix’

refers to the electrical configuration of keys, not the physical

arrangement. Consult Quantum for application assistance on

key design.

The 'fine' method of offset uses an 8-bit R2R ladder DAC

driven by the X drive lines to create an offset in the amplifier

stage. The DAC is driven after the burst has ceased and the

charge accumulated, so there is no conflict in this dual-use of

the X lines.

1.4 Communications

The device uses two variants of SPI communications,

Slave-only and Master-Slave. Over this interface is a

command and data transfer structure

Figure 1-6 Circuit Block Diagram (8x8 Matrix Shown)

designed for high levels of flexibility using

minimal numbers of bytes. For more

information see Sections 4 and 5.

Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7

X0

X1

X2

X3

X4

X5

X6

X7

X0

X1

X2

X3

X4

X5

X6

X7

Device variations: Refer to Section 3.1 for

differences between the parts covered by

this datasheet.

SPI

to

Host

2 Signal Processing

✟

X_{1..7}

X7

XS

The devices calibrate and process all

signals using a number of algorithms

specifically designed to provide for high

survivability in the face of adverse

environmental challenges. They provide a

large number of processing options which

can be user-selected to implement very

flexible, robust keypanel solutions.

Timing &

Charge

YC0 .

.

YC1

YC2 .

YC3

YC4 .

YC5

YC6 .

YC7

Neutralizing

Control

(PLD)

.

Transfer Strobe

Transfer Select

.

YS0..YS2

X0 .

.

X2 .

.

X4 .

.

X6 .

.

Transfer

M ux

X1

Signal Offset

Charge

R2R

DAC

X3

X5

XS

QT60xx5

AIN

Integrator

+

-

2.1 Negative Threshold

See also Command ^S, page 29

Sample layout artwork is available from Quantum on request.

The polarity of the Cs integrator capacitor reset drive can be

set for active high or active low operation using command ^S.

In the reference circuit show in Figure 3-1, the JFET will reset

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Bypass capacitors and series resistors can be used to

prevent these effects as shown in Figures 4-4 and 4-5.

3.22 ESD / Noise Considerations

In general the QT60xx5B will be well protected from static

discharge during use by the overlying panel. However, even

with a dielectric panel transients currents can still flow into

scan lines via induction or in extreme cases, dielectric

breakdown. Porous or cracked materials may allow a spark to

tunnel through the panel. In all cases, testing is required to

reveal any potential problems. The devices have diode

protected pins which can absorb and protect the device from

most induced discharges, up to 5mA.

4 Serial Interface

QT60xx5B devices use an SPI serial interface to a host MCU.

This port uses a protocol described in Section 5.

4.1 Serial Port specifications

QT60xx5's use an SPI synchronous serial interface with the

following specifications at 6MHz oscillator frequency:

The X lines are not usually at risk during operation, since they

are low-resistance output drives. The YCn lines are not

directly connected to the matrix and so are not at risk.

However the PLD and the QS3251 are connected to the Y

lines and may require additional ESD protection.

Max clock rate, Fck

Data length

Host command space, Tcm

Response delay to host, Tdr1

Drdy delay from response, Tdr2

Multi-byte return spacing, Tdr3

1.5MHz

8 bits

m 50µs

Table 4-1, also, Sec. 7

1µs to 1ms

15µs to 2ms

Diode clamps can be used on the X and Y matrix lines. The

diodes should be high speed / high current types such as

BAV99 dual diodes, connected from Vdd to Vss with the

diode junction connected to the matrix pin.

The host can clock the SPI at any rate up to and including the

maximum clock rate Fck. The maximum clock rate of the part

in Master mode is determined by Setup ^Q.

Capacitors placed on the X and Y matrix lines can also help

to a limited degree by absorbing ESD transients and lowering

induced voltages. Values up to 100pF can be used without

causing circuit problems.

The part can operate in either master-slave mode or

slave-only mode, and is thus compatible with virtually all

SPI-capable microcontrollers.

The circuit can be further protected by inserting series

resistors into the X and/or Y lines to limit peak transient

current. Values up to 500 ohms can be used in most cases,

but if the dwell time is short this resistance can cause a

reduction in signal gain. RC networks as shown in Figures

4-4 and 4-5 can provide enhanced protection against ESD

while also limiting the effects of external fields.

The SPI interface should not be used over long distances due

to problems with signal ringing and introduced noise etc.

unless suitably buffered or filtered with RC networks as

shown in Figures 4-4 and 4-5. Slower data rates with longer

RC timeconstants will provide enhanced resistance to noise

and ringing problems.

Conversion to asynchronous UART format can be

accomplished by using a microcontroller with conversion

firmware. Using such a conversion device the part can

communicate with Quantum's QmBtn PC software. Consult

Quantum for details.

External field interference can occur in some cases; these

problems are highly dependent on the interfering frequency

and the manner of coupling into the circuit. PCB layout

(Section 3.21) and external wiring should be carefully

designed to reduce the probability of these effects occurring.

Of particular note is the length of the connection from the

circuit to the key panel. This connection will act as an

antenna that will resonate at various radio frequencies to

cause interference, and thus should be very short. If RFI

pickup is a problem, the connections should be damped

using ferrite beads or low-value (22 - 100 ohm) series

resistors in all lines including any ground and power lines

running in parallel to the panel.

4.2 Protocol Overview

The SPI protocol is based entirely on polled data

transmission, that is, the part will not send data to the host of

its own volition but will do so only in response to specific

commands from the host.

Run-time data responses, such as key detection or error

information, requires simple single-byte functions to evoke a

response from the part.

SPI data noise: In some applications the host MCU can be

some distance from the sensor, with the interface coupled via

ribbon cable. The SPI link is particularly vulnerable to noise

injection on these lines; corrupted or false commands can be

induced from transients on the power supply or ground wiring.

Setup mode interactions mostly use 2-byte functions from the

host to cause the part to alter its behavior; these functions

also cause writes to the internal eeprom.

The concept of 'scope' is used to allow functions to operate

on individual keys or groupings of keys. The scope of

subsequent functions can be altered by short initial scope

instructions.

Figure 4-1 SPI Connections

Slave-Only

Master-Slave

See Section 5 for protocol details.

Host MCU

QT60xx5

Host MCU

QT60xx5

4.3 SPI Slave-Only Mode

DRDY

SS

P_IN

P_OUT

SCK

DRDY

SS

Refer to Figures 4-1 and 4-2. Select Slave-only by

floating Pin 37 (MS) or tying high via a m10K resistor. Pin

37 also functions as an oscilloscope sync output (Section

3.20) and should never be tied directly to a supply rail. In

Slave mode the host must always be in Master mode, as

it controls all SPI activity including clocking of the

SS

SCK

MISO

MOSI

MS

SCK

MISO

MOSI

MS

MISO

MOSI

SS

MISO

MOSI

Vdd

10K

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Figure 4-2 SPI Slave-Only Mode Timing

T

dr3

T

cm

T

dr2

dr1

DRDY

{from sensor}

SS

{from host}

SCK

{from host}

MOSI

{from host}

7 6 5 4 3 2 1 0

Optional Byte 2

Host Command Byte 1

Null Dummy Data

7 6 5 4 3 2 1 0

Null Dummy Data

7 6 5 4 3 2 1 0

MISO

{from sensor}

7 6 5 4 3 2 1 0

Invalid Data

7 6 5 4 3 2 1 0

Invalid Data

Response Data or Echo

Nth Response Data

{N = command dependent}

Figure 4-3 SPI Master/Slave Mode Timing

T

cm

dr1

dr3

SS

SCK

MOSI

7 6 5 4 3 2 1 0

Command Byte 1

from Host to sensor

7 6 5 4 3 2 1 0

Optional Byte 2

from host to sensor

Response Byte or Echo

from sensor to host

Nth Byte from sensor

{N = command dependent}

SS, SCK, MOSI originate from Host

Floating

SS, SCK, MOSI originate from sensor

interface in both directions. Unlike hardware SPI slaves,

QT60xx5's need processing time to respond to functions.

DRDY’ is used to let the host know when data is ready for

collection; it indicates to the host when data is ready in

response to a command so that the host can clock over the

data.

SS’ transitions either up or down, or the transmission will

fail; between bytes SCK should always idle low. SCK

should never float.

SS’ - Slave select - input only; acts as a framing signal to the

sensor from the host. SS’ must be low before and during

reception of data from the host. It must not go high again

until SCK line has returned low; during data or echo

response it must not go high until after the host has

sensed that DRDY’ has gone high from the device. SS’

must idle high. SS’ has an internal pullup resistor.

This mode requires 5 signals to operate:

MOSI - Master out / Slave in data pin; used as an input for

data from the host at all times. This pin should be

connected to the MOSI pin of the host device.

DRDY’ - Data Ready - active-low - indicates to the host that

the part is ready to send data back subsequent to a

command from the host. This pin idles high. The DRDY’

pin has an internal pullup resistor inside.

MISO - Master in / Slave out data pin; used as an output for

data to the host at all times. This pin should be connected

to the MISO pin of the host device.

SCK - SPI clock - input only clock pin from host. The host

must shift out data on the falling edge of SCK; the

QT60xx5B clocks data in on the rising edge of SCK.

Important note: SCK must idle low just before and after

Internal pullup resistors note: The internal pullup resistors

can range from 35k to 120k ohms. If RC filtering is used on

the SPI lines per Figure 4-4, this resistance may not be low

Table 4-1 Typical DRDY (Tdr1) Response Delays (Burst Length = 12)

Burst Spacing

Function Type

Setup - Put (affect 1 key)

250µs

10ms

40ms

300ms

800ms

3ms

300µs

10ms

40ms

300ms

800ms

2.7ms

1ms

400µs

500µs

10ms

1ms

10ms

40ms

300ms

800ms

2ms

10ms

40ms

300ms

800ms

2ms

10ms

40ms

Setup - Put (affect 8 keys)

Setup - Put (affect 64 keys)

Lock Reference Levels ('L') command

Calibrate command (all keys)

Get key errors (E), Get keys pushed (K)

All other commands

300ms

800ms

2.5ms

800us

300us

300ms

800ms

2.5ms

800us

300us

1ms

800us

300us

800us

300us

400us

300us

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3) When the sensor has the command echo or requested

data ready to send back to the host, it loads it into its SPI

Figure 4-4 Filtering SPI Slave-Only Connections

register and pulls DRDY’ low.

+5

QT60xx5 Circuit

10K 10K

Host MCU

P_IN

4) The host detects that the sensor has pulled DRDY’ low

and in turn the host pulls SS’ low.

X drives

(1 of 8

shown)

DRDY

SS

Xn

Ra

Ca

220

5) The host obtains the byte from the sensor by transmitting

a dummy byte (0x00) to the sensor.

P_OUT1

SCK

47pF

Ra

Ca

SCK

MISO

6) The sensor releases DRDY’ to float high.

MISO

7) After the host detects that DRDY' has floated high the

host must allow SS’ to also float high.

Ca

Y Lines

(1 of 8

shown)

Yn

MOSI

100

22pF

8) For multi-byte responses, steps (3) through (7) are

repeated until the return data is completely sent.

Ca

P_OUT2

RESET

1K

(MS not

shown)

1nF

The host must release the SS’ line in step (7) even between

multiple byte responses because the QT60xx5B waits for the

SS’ line to return high before signalling that the next byte is

ready for collection.

Figure 4-5 Filtering SPI Master-Slave Connections

+5

The host should check the DRDY’ line and wait for it to go

high before transmitting another byte. Until the DRDY’ line is

released the sensor is still processing a data return, even if

the complete response data has been fully transferred; the

sensor may still be busy when the host finishes the byte

transfer and may not be able to digest a new command

immediately.

QT60xx5 Circuit

10K

Host MCU

SS

X drives

(1 of 8

shown)

DRDY

SS

Xn

220

47pF

Ra

Ca

SCK

Ca

MISO

See Section 3.18, page 15, for a description of the Alert pin

which can be used to reduce communication traffic.

Y Lines

(1 of 8

shown)

Yn

MOSI

100

22pF

Ra

1K

Ca

P_OUT

RESET

4.4 SPI Master-Slave Mode

(MS not

shown)

1nF

Refer to Figures 4-1 and 4-3. In Master-Slave mode the host

and sensor take turns being Master; the host always initiates

in Master mode during an exchange. The current Master

always controls all 3 signals. The sensor takes a variable

amount of time to respond to the host, depending on the

function and current and pending tasks. SPI Master/Slave

mode is selected by tying Pin 37 (MS) low via a 10K resistor.

Pin 37 is also an oscilloscope sync output (see Section

3.20 and command ^R, page 29) and should never be tied

directly to either supply rail. The host, like the sensor, must

idle in slave mode when not sending a command.

Recommended Values of Ra & Ca for Figures 4-4 and 4-5

SPI Clock Rate

1.5MHz

375kHz

Ra

680

Ca

100pF

270pF

470pF

1nF

1,000

2,200

93.75kHz

46.875kHz

enough to ensure adequate signal risetime and may need to

be augmented with external 10k pullups.

Master/Slave requires 3 signals to operate:

The host must wait until DRDY’ goes low before an SPI

transfer to retrieve data. For multi-byte responses, the host

must observe DRDY' to see when it goes high again after

each data byte, then low again, before executing another

transfer to get the next data byte. The host should send null

bytes (0x00) to retrieve data.

MOSI - Master out / Slave in data pin - bidirectional - an input

pin while the host is transmitting data; an output when the

sensor is transmitting data. The MOSI of the host and

slave should be tied together. The MISO lines are not used

on either part and should be left open.

If the DRDY’ line does not go low after a command, the

command was not properly received or it was inappropriate.

The delay to DRDY’ low depends on how many bytes of data

are being loaded into eeprom; Table 4-1. Absolute worst case

delays are found in Section 7; these timings occur only rarely,

for example if the device happens to be busy with adjacent

key suppression calculations, which occurs only at the

moment when a key is first detected.

SCK - SPI clock - bidirectional - an input pin when receiving

data; an output pin when sending. The host must shift out

data on the falling edge of SCK; the QT60xx5B clocks data

in on the rising edge of SCK. Important note: SCK from

the host must be low before asserting SS’ low or high at

either end of a byte or the transmission will fail. SCK

should idle low; if in doubt, a 10K pulldown resistor should

be used. When the sensor returns data it becomes the

Master; data is shifted out by it on the falling edge of SCK

and should be clocked in by the host on the rising edge.

A typical Slave-only function sequence is as follows:

1) The host pulls SS’ low, then transfers a command to the

sensor. The host then releases SS’ to float high. DRDY’ is

unaffected in this step.

SS’ - Slave select - bidirectional framing control. When the

sensor is in slave mode, this pin accepts the SS’ control

signal from the host. In either data direction, SS' must go

low before and any during data transfer; it should not go

high again until SCK has returned low at the end of a byte.

2) For 2-byte functions, (1) is repeated with a m50µs delay.

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In Master mode the sensor asserts control over this line, to Commands that return data do not send back a command

make the host a slave and to frame the data. This line

must idle high; the part includes an internal pullup resistor

and should be floated during idle times.

echo. If desired, the command can be verified via the 'l'

(lowercase L) echo function; see page 28.

The host should not transmit a new command until the

Internal pullup resistor note: The internal pullup resistor on last command has been processed and responded to

SS’ can range from 35k to 120k ohms. If RC filtering is used

on the SPI lines per Figure 4-5, this pullup resistance may not

be low enough to ensure adequate signal risetime and may

need to be augmented with external 10k pullups.

completion, plus 1ms.

Commands that are not recognized are ignored, and the host

should monitor for timeouts to detect these conditions. If this

occurs a new command should not be sent until the specified

timeout duration has expired.

A command may consist of one or two bytes with a m50µs

delay between bytes. At the end of a full command, the host

must go into Slave mode to await a response.

The maximum timings shown in Table 4-1 and Section 7-5

are guaranteed provided that the part is operating within the

timing limitations of Section 5.7. If burst timing is in violation,

the response time to a command may be longer.

The sensor may take some time to process the command

and respond. When it does, it asserts SS’ low and begins

clocking data out. For multi-byte responses, bytes will be sent

at intervals which may be irregular depending on the request

and the processing load of the sensor. The host must be

prepared to accept the sensor data as it comes or there can

be a data overrun in the host. If the data returns too quickly

for the host to accept it, lower the SPI clock rate.

4.6 Eeprom Corruption

The device stores its Setup data in an internal eeprom which

can be readily altered via Put mode commands. Sometimes

noise on Vdd, the SPI lines or Reset pin can cause eeprom

corruption which can be difficult or inconvenient to correct.

A typical Master-Slave function sequence is as follows:

The device should always be left in Get mode to prevent

spurious commands from corrupting the eeprom. The Get

command should ideally be repeated every second or so to

ensure that if noise on the SPI lines causes a false Put mode

command that it does not last long. Preferably, the ‘l’

command (lowercase ‘L’) should be used to verify that the Put

command has succeeded.

1) Host enters Master mode. The sensor is already in Slave

mode.

2) The host pulls SS’ low, then transfers one byte of

command to the sensor via MOSI, then releases SS’ to

float high again.

3) For 2-byte functions, (2) is repeated with m50µs spacings

between bytes.

Flash backup: The part backs up the entire eeprom array

into onboard Flash rom after one or more Setup write

4) The host immediately places its SPI port into Slave mode, commands have been issued and the part is then reset.

floating SCK and MOSI’; SS’ stays floating.

During normal operation the part constantly compares the

Flash area with the eeprom array to ensure the two sections

match. If an eeprom error is detected, the device sets an

error flag (bit 4) in the general device status byte (Command

‘7’, page 22) which can be read by the host device. The LED

output also becomes active. If the bit 4 error flag is set, the

host should immediately induce a device reset.

5) When the sensor has a command echo or data to send

back, it puts its SPI register in Master mode, taking control

over MOSI and SCK. SS' remains floating.

6) The sensor pulls SS’ low, then clocks out its response

byte to the host, then floats SS’ high again.

7) The sensor repeats (6) as necessary for multiple byte

responses.

Bit 4 is also set if an intentional write has been made to

eeprom, but not yet copied into Flash via the reset process. It

is perfectly acceptable to continue altering any number of

Setup parameters prior to doing the reset, ignoring this bit.

8) The sensor returns to slave mode.

After the transmission sequence, the SPI lines float high or

are left to float in an indeterminate state (MOSI) until the next

transmission sequence is initiated by the host. The host

should wait for m1ms after a sequence before initiating

another transmission sequence.

During power up or after a reset, the device compares the

Flash area with eeprom, and if there is a discrepancy the

eeprom is refreshed from Flash, unless an intentional write

was detected in which case the Flash is updated from the

eeprom. As intentional writes in Put mode should only occur

during manufacture, it is normally safe to assume that

eeprom changes during normal run mode are errors.

See Section 3.18, page 15, for a description of the Alert pin

which can be used to reduce communication traffic.

The host can also periodically test the checksum of the

eeprom as a backup mechanism to the bit 4 error flag.

4.5 Sensor Echo and Data Response

The devices respond to each and every valid command from

the host with at least one return byte. In the case of functions

that do not send data back to the host, the part returns the

command itself as an echo, but only after the function has

been completed; this also holds for 2-byte functions where

the second byte is an operand: in these cases the return byte

is an echo of the command, not the operand.

The uppercase ‘L’ command, Lock Reference Levels, also

writes data to eeprom, and this data also has the potential to

become corrupted. This data is also backed up in Flash so

that it can be recovered, and an error in this data will also set

bit 4 and also alter the checksum. Also, the ‘L’ command only

operates if the device is in Put mode as a further protection.

Flash rom has a limit of 1,000 write cycles, so copy-to-Flash

should not be used routinely.

Exception: The recalibration command ‘b’ returns an

acknowledgement immediately rather than just before the

actual recalibration.

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5.1 Direction Commands

5 Commands & Functions

Setup commands can be used to either send control

information to the part for programming into its internal

eeprom, or to extract the current setting of this information.

The same Setup function can do either. To accomplish this

the device relies on direction control via the Get and Put

commands. In Get mode, a Setup command will return

information. In Put mode, the behavior of the device is

altered, and often a second operand byte must be sent.

The command structure is designed to minimize control and

data traffic. All repetitive data and status commands from the

host are single-byte, and most commands result in single-

byte device responses. Behavioral setup commands involve

multiple bytes but these are infrequently used.

Special 'scope' commands exist to restrict subsequent

commands to a specific key or range of keys. This control

structure permits most matrix keys, which are usually

identical in shape and size, to be programmed 'in bulk' using

a 'global' scope command, followed by a scope restriction to

specific key(s), followed by more key programming, to

prevent the need for tedious key-by-key programming across

an entire matrix.

The powerup or reset default mode is Get. The current

Get/Put mode persists until countermanded by a different

Get/Put command or until the device is reset or powered off.

It is advisable to use Put mode only when actually writing

Setups to the device, which will happen infrequently; the part

should normally be left in Get mode. Get mode acts as a lock

to prevent accidental changes to the internal eeprom.

There are four types of commands:

Direction - Determine whether subsequent commands are

used to get data from or put data to the part;

Multiple direction commands of the same type (g, g, g, g ...)

are harmless and can be used to insure that the part does not

accidentally enter Put mode for a prolonged period, for

example due to noise glitches on the SPI lines. The 'g'

command can be repeated every few seconds.

Scope - Restrict the range of effect of subsequent

commands to a specific set of keys;

Status - Cause the part to respond with key information,

such as detections, signals, error codes, and the like;

g

0

X

67 - GET

Scope

n/a

C

OMMAND

Setup - Modify functionality such as burst length, threshold

levels, drift compensation characteristics, etc.

Bytes / Cmd 2nd Byte Range

Returns

0x67

n/a

Put

Get

1

n/a

Supervisory - Special functions such as diagnostics,

calibration, etc. which affect the part as a whole.

n/a

Lowercase 'G'. The 'g' command causes the device to treat all

subsequent Setup commands as 'Gets'; after, when a Setup

command is received from the host the part will respond by

sending back the current status of that Setup parameter.

All command types can be intermixed. Even during normal

device operation it is possible to use Setup and Supervisory

functions to alter key behavior on the fly. There is no special

'setup mode'.

The 'g' command is always single-byte and echoes back

itself.

Get/Put, Scope, and many Supervisory functions are volatile

and do not persist after a power down or reset cycle. Some

Supervisory commands require that the part be reset in order

for the new settings to take effect.

p

0

X

70 - PUT

Scope

n/a

C

OMMAND

Bytes / Cmd 2nd Byte Range

Returns

0x70

n/a

Note that the Setup functions write to eeprom and require

extra time for a response back to the host. Also note that as

with all eeprom memories there is a recommended lifetime

limit to the number of writes; this limit is 100,000 cycles.

Put

Get

1

n/a

Lower case 'p'. The 'p' command causes the device to treat

all subsequent Setup commands as 'Puts'; after, when a

2-byte Setup command is received from the host the part will

respond by programming in the desired parameter for the

key(s) which are affected.

Command functions are summarized in Section 5-6

It is highly advised to test the device checksum

(command ‘6’) or individual key settings or the general

device status (‘7’) once Setups have been programmed

into the part, each time the part is powered up and

periodically while running.

The 'p' command is always single-byte and echoes back

itself.

The part backs up all eeprom locations into Flash

memory, from which data is restored automatically

following a reset if eeprom corruption is detected. The

part should also be reset after any Put command(s) in

order to force the copy of eeprom data into Flash. See

Section 4.6.

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5.2 Scope Commands

5.3 Status Commands

Status commands cause the sensor to report back

information related to keys and their signals.

The host should always set the scope parameter when

initializing the part during normal operation as well as during

setup. Scope commands are persistent and apply to all

subsequent functions that are affected by scope, until a

different scope command is issued. On powerup or after reset

the device defaults to scope = 'all keys'.

It is not necessary to set the part to Get mode with these

commands, although it is advised to leave the part in Get

mode as a normal precaution (see Section 5.1)

Many functions only address one key regardless of the

current scope; in these cases the key being addressed is

always the key last set by the 's' or 'x' and 'y' commands. If

the 's' command was last set to key #9 (x=1, y=1), then even

though the 'S' command was issued afterwards the one-key

scope will remain key '9'. If 'x' were subsequently set to 2 then

one-key scope will be key x=2, y=1 (key #10). If 'y' were

subsequently set to 3, then one-key scope will be key x=2 /

y=3 (key #26). This rule operates for commands in either Put

or Get modes.

0

X

30 - SIGNAL FOR

S

Bytes / Cmd # Bytes Rtnd

INGLE

K

EY

Scope

n/a

Returns

n/a

0x00..0xFF

Put

Get

n/a

1

n/a

1

Numeric '0'. Returns the signal level in 8-bit unsigned binary

for one key whose location is determined by scope. Note that

the signal level is inverted: decreasing values correspond to

more touch due to the physics of key detection described in

Section 1.1.

Key numbering convention: The numbering of keys goes by

row then column. For example, the key in row X=3, column

Y=1 (X3Y1) is key 11. The formula for conversion of an X-Y

location to a key number is:

1

0

X

31 - DELTA

S

IGNAL FOR

S

Bytes / Cmd # Bytes Rtnd

INGLE

K

EY

Scope

n/a

Returns

n/a

0x00..0xFF

Put

Get

n/a

1

n/a

1

key_number = X_row + (Y_column x 8)

Row and column numbers are per Fig. 1-6. Keys are acquired

in this same burst sequence, i.e. X0Y0, X1Y0, X2Y0 etc.

Numeric '1'. Returns the value {Reference - Signal} in

unsigned 8-bit binary for one key whose location is

determined by scope. If Signal > Reference, the result is

truncated to zero.

s

0

X

73 - SPECIFIC

K

Bytes / Cmd 2nd Byte Range

EY

S

COPE

Scope

n/a

Returns

0x73

n/a

Increasing amounts of this value correspond to increasing

amounts of touch as the sign of signal is inverted (see 0x30

above).

Put

Get

2

n/a

0x00..0x3F

n/a

Lowercase 'S'. Targets a specific individual key for all further

functions that are affected by scope. The second byte must

contain a binary key number from 0..63 decimal.

2

0

X

32 - REFERENCE

V

Bytes / Cmd # Bytes Rtnd

ALUE

Scope

n/a

Returns

n/a

0x00..0xFF

Put

Get

n/a

1

n/a

1

S

0

X

53 - ALL

Scope

n/a

K

EYS

S

Bytes / Cmd 2nd Byte Range

COPE

Returns

0x53

n/a

Numeric '2'. Returns the Reference value in unsigned 8-bit

binary for one key whose location is determined by scope.

Put

Get

1

n/a

3

0

X

33 - R2R OFFSET

Uppercase 'S'. Addresses all keys in the matrix for all further

functions that can target a group of keys.

Scope

n/a

Bytes / Cmd # Bytes Rtnd

Returns

n/a

0x00..0xFF

Put

Get

n/a

1

n/a

1

x

0

X

78 - ROW

Scope

n/a

K

EYS

S

Bytes / Cmd 2nd Byte Range

COPE

Returns

0x78

n/a

Section 1.2, p. 4

Put

Get

2

n/a

0x00..0x07

n/a

Numeric '3'. Returns the R2R offset value in unsigned 8-bit

binary for one key whose location is determined by scope.

This function is useful primarily for circuit diagnostics or for an

independent determination of proper circuit operation.

n/a

Lowercase 'X'. Targets keys in a specific row for functions

that can address key groups. The second byte must contain a

row number from 0..7. This command also affects scope for

single-key commands.

4

0

X34 - C

Z

S

TATE

Scope

n/a

Bytes / Cmd # Bytes Rtnd

Returns

n/a

0x00..0x02

y

0

X

79 - COLUMN

K

Bytes / Cmd 2nd Byte Range

EYS

S

COPE

Put

Get

n/a

1

n/a

1

Scope

n/a

Returns

0x79

n/a

1

Put

Get

2

n/a

0x00..0x07

n/a

Section 1.2, p. 4

Numeric '4'. Returns the Cz state for one key whose location

is determined by scope. This function is useful primarily for

circuit diagnostics or for an independent determination of

circuit operation after calibration. A higher value indicates

more Cz cancellation is being applied to compensate for Cx;

a value of 2 indicates both Cz caps are being switched in.

Lowercase 'Y'. Targets keys in a specific column for functions

that can address key groups. The second byte is a binary

column number from 0..7. This command also affects scope

for single-key commands.

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5

0

X

35 - DETECTION

I

NTEGRATOR

C

Bytes / Cmd # Bytes Rtnd

OUNTS

<

SP> 0

X

20 - SIGNAL

L

EVELS FOR

G

Bytes / Cmd # Bytes Rtnd

ROUP

Scope

n/a

Returns

n/a

0x00..0xFF

Scope

n/a

8, 64

Returns

n/a

0x00..0xFF

Put

Get

n/a

1

n/a

1

Put

Get

n/a

1

n/a

8 or 64

1

Numeric '5'. Returns the Detection Integrator counter value

for one key whose location is determined by scope. This

function is useful primarily for circuit diagnostics.

Space character. Same function as 0x30 above except

returns a group response of 8 bytes (if Scope = row or

column selected) or 64 bytes (if Scope = entire matrix

selected). If no group scope has been selected, returns data

for all keys (64 bytes).

6

0

X

36 - EEPROM

CHECKSUM

Bytes / Cmd # Bytes Rtnd

Scope

n/a

Returns

n/a

0x00..0xFF

!

0

X

21 - DELTA

Scope

n/a

S

IGNALS FOR

G

Bytes / Cmd # Bytes Rtnd

ROUP

Put

Get

n/a

1

n/a

1

Returns

n/a

0x00..0xFF

Put

Get

n/a

1

n/a

8 or 64

8, 64

Numeric '6'. Returns the entire eeprom checksum. This

function is useful primarily for diagnostics and should

periodically be used to check for valid eeprom contents.

Exclamation character. Same function as 0x31 above except

returns a group response for 8 or 64 keys depending on

current scope. If no group scope has been selected, returns

data for all keys (64 bytes).

The checksum should be computed when the entire device's

settings, including the locked reference levels ('L' command)

are set. The host can then periodically test the checksum to

validate eeprom integrity. If needed, the eeprom can then be

reprogrammed by the host or the device can be reset to allow

the eeprom to be updated from Flash ROM (see Section 4.6).

"

0

X

22 - REFERENCE

L

Bytes / Cmd # Bytes Rtnd

EVELS FOR

G

ROUP

Scope

n/a

8, 64

Returns

n/a

0x00..0xFF

Put

Get

n/a

1

n/a

8 or 64

The checksum is a simple 8-bit carry fold-back type. Changes

to multiple Setups can generate identical checksums.

Changes to one location only will always produce a different

checksum. An identical change to 2, 4, 8, 16, 32 or 64 keys is

more prone to generating an identical checksum. A unique

checksum can be obtained again by altering any Setup for

another key (i.e. an unused key) to be different.

Double quote character. Same function as 0x32 above except

returns a group response of 8 or 64 bytes depending on

current scope. If no group scope has been selected, returns

64 bytes.

#

0

X

23 - R2R OFFSET FOR

G

Bytes / Cmd # Bytes Rtnd

ROUP

After any Setups change, the checksum will not be valid until

after the device has been reset.

Scope

n/a

8, 64

Returns

n/a

0x00..0xFF

Put

Get

n/a

1

n/a

8 or 64

Note that the general status byte returned by the ‘7’

command contains a bit that is set if there is an error in

eeprom data; this feature operates independently of the

checksum command.

Hash character. Same function as 0x33 above except returns

a group response of 8 bytes (Scope = row or column

selected) or 64 bytes (Scope = entire matrix selected)

depending on the current group scope setting. If no group

scope has been selected, returns 64 bytes.

There is no put version of the command.

7

0

X

37 - GENERAL

D

Bytes / Cmd # Bytes Rtnd

EVICE

S

TATUS

Scope

n/a

Returns

n/a

0x00..0x1F

$

0

X

24 - CHARGE

C

Bytes / Cmd # Bytes Rtnd

ANCELLATION FOR

G

ROUP

Put

Get

n/a

1

n/a

1

Scope

n/a

8, 64

Returns

n/a

0x00..0x03

Put

Get

n/a

1

n/a

8 or 64

Section 2.12, p. 8

Dollar character. Same function as 0x34 above except returns

a group response of 8 bytes (Scope = row or column

selected) or 64 bytes (Scope = entire matrix selected)

depending on the current group scope setting. If no group

scope has been selected, returns 64 bytes.

Numeric '7'. Returns the part's general status byte which is a

5-bit pattern as follows:

b7

u

b6

u

b5

u

b4

EF

b3

SF

b2

KE

b1

KR

b0

KD

KD: 1= one or more keys are in detection

KR: 1= one or more keys are recalibrating

KE: 1= one or more keys are reporting errors

SF: 1= sync fail; the part is not synchronized to an

external source (if in that mode; see Section 3.17).

EF: 1 = Eeprom / Flash discrepancy (Section 4.6)

%

0

X

25 - DETECT

I

NTEGRATOR

C

Bytes / Cmd # Bytes Rtnd

OUNTS FOR

G

ROUP

Scope

n/a

8, 64

Returns

n/a

0x00..0xFF

Put

Get

n/a

1

n/a

8 or 64

Percent character. Same function as 0x35 above except

returns a group response of 8 bytes (Scope = row or column)

or 64 bytes (Scope = entire matrix) depending on the current

group scope setting. If no group scope has been selected,

returns 64 bytes.

Higher bits (‘u’) report as 0's and are not used.

This command can be used as a general 1-byte status

response; if one or more bits are set, the host can take

interrogate further to narrow down specifics, such as which

key is being touched or in error, via other commands.

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The bitfields for a global response are:

b7 b6 b5 b4 b3

e

0

X

65 - ERROR

C

ODE FOR

S

Bytes / Cmd # Bytes Rtnd

ELECTED

K

EY

Scope

n/a

Returns

n/a

0x00..0x0F

b2

b1

b0

X7Y0 X6Y0 X5Y0 X4Y0 X3Y0 X2Y0 X1Y0 X0Y0

Put

Get

n/a

1

n/a

1

byte1

byte2

byte3

byte4

byte5

byte6

byte7

byte8

1

7

6

5

4

3

2

1

0

X7Y1 X6Y1 X5Y1 X4Y1 X3Y1 X2Y1 X1Y1 X0Y1

15 14 13 12 11 10

X7Y2 X6Y2 X5Y2 X4Y2 X3Y2 X2Y2 X1Y2 X0Y2

23 22 21 20 19 18 17 16

X7Y3 X6Y3 X5Y3 X4Y3 X3Y3 X2Y3 X1Y3 X0Y3

31 30 29 28 27 26 25 24

X7Y4 X6Y4 X5Y4 X4Y4 X3Y4 X2Y4 X1Y4 X0Y4

39 38 37 36 35 34 33 32

X7Y5 X6Y5 X5Y5 X4Y5 X3Y5 X2Y5 X1Y5 X0Y5

47 46 45 44 43 42 41 40

X7Y6 X6Y6 X5Y6 X4Y6 X3Y6 X2Y6 X1Y6 X0Y6

55 54 53 52 51 50 49 48

X7Y7 X6Y7 X5Y7 X4Y7 X3Y7 X2Y7 X1Y7 X0Y7

63 62 61 60 59 58 57 56

Section 2.12, p. 8

9

8

Lowercase 'E'. Returns the error byte for a selected key

defined by the 's' command. A 4-bit pattern is returned:

b7

u

b6

u

b5

u

b4

u

b3

L

b2

H

b1

R

b0

F

F: 1= failed last full recalibration attempt

R: 1= key is in process of full recalibration

H: 1= key reference is high (above normal bounds)

L: 1= key reference is low (below normal bounds)

u: undefined

Refer also to Section 2.10.

Byte 1 is the first returned byte in the sequence.

F, Bit 0 is set if it failed to calibrate properly during a forced

recalibration. The sensor will automatically make 5 sequential

attempts at recalibration before setting this flag.

In all the above examples a '1' in a bit position indicates that

there is some type of error associated with the key. The use

of the 'e' command (or 'E' with scope set to a specific key) will

specify the nature of the error.

R, Bit 1 is set if the key is in the process of a full

recalibration. When set, bits 2 and 3 are immediately cleared.

k

0

X

6B - REPORTING OF

F

Bytes / Cmd

IRST

T

OUCHED

K

#Bytes Rtnd

EY

H, Bit 2 when set indicates either:

Scope

n/a

Returns

n/a

0x00..0xFF

- the reference has drifted above decimal 191, or,

- the total absolute reference level has become higher than

the upper window boundary described in Section 2.11

and as defined by Command ^N after a forced

recalibration.

Put

Get

n/a

1

n/a

1

Section 2.12, p. 8

Lowercase 'K'. Returns a byte that indicates which if any key

has been touched. The byte is structured as follows:

L, Bit 3 when set indicates either:

- the reference has drifted below decimal 64, or,

- the total absolute reference level has become lower than

the lower boundary described in Section 2.11, as defined

by Command ^O after a forced recalibration.

b7

m

b6

-

b5

k5

b4

k4

b3

k3

b2

k2

b1

k1

b0

k0

Bits are used as follows:

m - if '1', indicates that yet another key is active

Bits 2 and 3, if set via drift compensation, would indicate that

the key should be recalibrated by the host. If H and L bits

appear immediately after a full recalibration, it means that the

key is probably defective.

k0..k5 - indicates the key number of a first detected key,

in the range 0..63 (0x00..0x3F).

If a reported key drops out while other keys are active, 'k' will

report one of the other active keys, but there is no rule for

which of the next keys gets reported in k0..k5.

E

0x45 - Error Codes for Group

Scope

n/a

1, 8, 64

Bytes / Cmd # Bytes Rtnd

Returns

n/a

0x00..0xFF

If the byte returned has a value of 255 (0xFF), then no key

has been detected.

Put

Get

n/a

1

n/a

1 or 8

Section 2.12, p. 8

Uppercase 'E'. Returns general error codes for a range of

keys defined by scope. Returns either 1 or 8 bytes depending

on whether a single key, row, column, or entire matrix are

selected.

The bitfields for a single key are the same as for 'e' above.

The bitfields for a single row (X) are:

b7

Y7

b6

Y6

b5

Y5

b4

Y4

b3

Y3

b2

Y2

b1

Y1

b0

Y0

The bitfields for a single column (Y) are:

b7

X7

b6

X6

b5

X5

b4

X4

b3

X3

b2

X2

b1

X1

b0

X0

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K

0

X

4B - KEY

Scope

n/a

T

OUCH

R

Bytes / Cmd # Bytes Rtnd

EPORTING FOR

G

ROUP

5.4 Setup Commands

Returns

n/a

0x00..0xFF

Setup functions are those that alter the behavior a key or a

group of keys. The setups are programmed into eeprom

locations in the part and ordinarily do not need to be

reprogrammed once set. However it is possible to change a

setup while the device is in normal operation without

interrupting the sensing function of the part.

Put

Get

n/a

1

n/a

1 or 8

1, 8, 64

Section 2.12, p. 8

Uppercase 'K'. Returns 1 or 8 bytes depending on the current

scope. The byte(s) returned contain a bit pattern which

indicates touched keys. A scope of a single key, row or

column will return one byte. A scope of all keys will return 8

bytes. If scope is one key, only the LSB is used to report.

Setup functions alter the internal eeprom, and this requires a

much longer time to complete than other commands; see

Table 4-1.

Setup 'put' commands become effective immediately after the

echo response of the command byte unless otherwise noted;

some setups require that the key(s) being altered be

The bitfields for a single key are:

b7

-

b6

-

b5

-

b4

-

b3

-

b2

-

b1

-

b0

key

recalibrated with the 'b' command before they take effect.

The bitfields for a single row (scope is X) are:

^A 0

X

01 - NEGATIVE

D

ETECT

T

Bytes / Cmd Byte 2 Range

HRESHOLD

b7

Y7

b6

Y6

b5

Y5

b4

Y4

b3

Y3

b2

Y2

b1

Y1

b0

Y0

Scope

1, 8, 64

1

Returns

0x01

0x04..0x40

Put

Get

2

1

0x04..0x40

n/a

The bitfields for a single column (scope is Y) are:

Section 2.1, p. 5

b7

X7

b6

X6

b5

X5

b4

X4

b3

X3

b2

X2

b1

X1

b0

X0

Ctrl-A. In Put mode, the command followed by a setting is

programmed into eeprom for the key(s) affected by scope.

The bitfields for a global report are:

1, 8, or 64 keys may be affected. Valid decimal values are:

b7 b6 b5 b4

b3

b2

b1

X7Y0 X6Y0 X5Y0 X4Y0 X3Y0 X2Y0 X1Y0 X0Y0

b0

byte1

byte2

byte3

byte4

byte5

byte6

byte7

byte8

4

5

6

7

17 20 25 30 35 45 55 64

8

10 12 15

7

6

5

4

3

2

1

0

X7Y1 X6Y1 X5Y1 X4Y1 X3Y1 X2Y1 X1Y1 X0Y1

15 14 13 12 11 10

X7Y2 X6Y2 X5Y2 X4Y2 X3Y2 X2Y2 X1Y2 X0Y2

23 22 21 20 19 18 17 16

X7Y3 X6Y3 X5Y3 X4Y3 X3Y3 X2Y3 X1Y3 X0Y3

31 30 29 28 27 26 25 24

X7Y4 X6Y4 X5Y4 X4Y4 X3Y4 X2Y4 X1Y4 X0Y4

39 38 37 36 35 34 33 32

X7Y5 X6Y5 X5Y5 X4Y5 X3Y5 X2Y5 X1Y5 X0Y5

47 46 45 44 43 42 41 40

X7Y6 X6Y6 X5Y6 X4Y6 X3Y6 X2Y6 X1Y6 X0Y6

55 54 53 52 51 50 49 48

X7Y7 X6Y7 X5Y7 X4Y7 X3Y7 X2Y7 X1Y7 X0Y7

63 62 61 60 59 58 57 56

Values other than the above will be rounded down.

9

8

In Get mode, the command will return a single byte according

to the rules of Section 5.2, page 21.

This setup controls key sensitivity by setting the counts of

signal delta needed to cause a detect. Higher = less

sensitive. Numbers should be 6 or greater under most

conditions to reduce the probability of noise detection.

Numbers greater than 20 indicate that the burst length is

probably too high. This setup interacts with Burst Length (^F).

^B 0

X

02 - POSITIVE

D

ETECT

T

Bytes / Cmd Byte 2 Range

HRESHOLD

Scope

1, 8, 64

1

Returns

0x02

0x04..0x40

Byte 1 is the first returned byte in the sequence.

Put

Get

2

1

0x04..0x40

n/a

In all the above examples a '1' in a bit position indicates that

the key is touched; a '0' indicates no touch.

Section 2.2, p. 6

Ctrl-B. In Put mode, the command followed by a setting is

programmed into eeprom for the key(s) affected by scope. 1,

8, or 64 keys may be affected. Valid decimal values are:

4

5

6

7

17 20 25 30 35 45 55 64

8

10 12 15

Values other than the above will be rounded down.

In Get mode, the command will return a single byte according

to the rules of Section 5.2, page 21.

This setup controls the ability of a key to recalibrate quickly

should the signal transition positive quickly, as when a touch

is prolonged enough to cause a recalibration, and when the

key is then 'untouched'. This condition can also be caused by

a foreign object being removed from a key. The value should

normally be set between 6 and 10 counts. If the value is very

high, the key will still recover by means of the drift

compensation process, albeit more slowly.

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^C 0

X

03 - NEGATIVE

T

HRESHOLD

H

Bytes / Cmd Byte 2 Range

YSTERESIS

^F

0

X

06 - BURST

Scope

1, 8, 64

1

L

ENGTH

Scope

64

Returns

0x03

0x01..0x03

Bytes / Cmd Byte 2 Range

Returns

0x06

0x00..0x40

Put

Get

2

1

0x01..0x03

n/a

Put

Get

2

1

0x00..0x40

n/a

Section 2.3, p. 6

Section 3.6, p. 12

Ctrl-C. In Put mode, the command followed by a setting is

programmed into eeprom for all keys only. The value should

be from 0 to 3, representing hysteresis as follows:

Ctrl-F. In Put mode the command sets the burst length of one

or more keys, according to the current scope. Valid decimal

values are:

0: 50%

1: 25%

0

1

2

3

4

5

12 15 20 25 30 40 50 64

7

10

2: 12.5%

3: 0% (no hysteresis)

Values other than the above will be rounded down.

In Get mode, the command will return a single byte according

to the rules of Section 5.2, page 21.

Values other than the above will be rounded down.

The percentage is the distance from the threshold level to the

reference level. The hysteresis level is always closer to the

threshold point than to the reference point. 25% is a

reasonable value under most conditions.

^F sets the length of the acquisition burst on a key by key

basis. This setting is directly proportional to signal gain. This

setup interacts with Negative and Positive Threshold (^A and

^B). Increasing ^F can allow for higher threshold levels and

more robust signals, at the expense of increased radiated

emissions and reduced Cx load capacity.

As this parameter is common to all keys, Put and Get

operations send or return only one byte.

Special condition: If the value for ^F for a key is set to zero

the burst disabled and the key will not function; the key will

report back with an error code. The timing for the 'phantom

burst' will be preserved so that overall key scan timing will

remain unchanged.

^D 0

X

04 - POSITIVE

T

HRESHOLD

H

Bytes / Cmd Byte 2 Range

YSTERESIS

Scope

64

Returns

0x04

0x01..0x03

Put

Get

2

1

0x01..0x03

n/a

Section 2.3, p. 6

^G 0

X

07 - BURST

SPACING

Bytes / Cmd Byte 2 Range

Ctrl-D. Identical in operation to ^C above except this applies

to positive 'detections' used to recalibrate the sensor (see ^B

above for details). Uses same hysteresis values as ^C above.

Scope

64

Returns

0x07

0x00..0x05

Put

Get

2

1

0x00..0x05

n/a

Section 3.8, p. 12

^E 0

X

05 - DWELL

T

IME IN

M

Bytes / Cmd Byte 2 Range

ACHINE

C

YCLES

Scope

64

Returns

0x05

0x01

Ctrl-G. In Put mode, sets the spacing between successive

acquire bursts for the entire matrix.

Put

Get

2

1

0x01

n/a

The second byte indicates the spacing to be set according to

the following values:

Sections 1.2, 3.3, 3.9, 3.13

0: 250µs

1: 300µs

2: 400µs

3: 500µs

4: 1000µs

5: 2000µs

Ctrl-E. Governs the delay from the rise of an X drive to the

termination of Y transfer gating ('dwell time').

This command is included for compatibility with future

versions. The device defaults to 1 (one) machine cycle of

dwell or 167ns with a 6MHz oscillator. Although the command

will be accepted, this setting cannot be changed.

Values higher than the above will be truncated to 2000µs.

The dwell time can be shortened below 167ns by an external

circuit as described in Section 3.9.

Longer delay times equate to slower acquisitions. At lower

delay times (faster rep rates) there can be conflicts with long

burst lengths which will prevent proper operation; see Section

5.7.

As this parameter is common to all keys, Put and Get

operations send or return only one byte, 0x01.

The time required to scan the entire keymatrix once is the

above delay multiplied by 64 regardless of the number of

keys actually used or the part model number.

Burst spacing also affects recalibration time; see Section 2.10

The scope for this function is always 'all keys'.

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The unit of measure is a burst, i.e. a setting of 5 means that a

^H 0

X

08 - NEGATIVE

D

RIFT

C

Bytes / Cmd Byte 2 Range

OMPENSATION

R

ATE

detection must be sensed 5 bursts in sequence. A burst for a

key occurs once every complete matrix scan. Thus, if the

burst spacing is 500us, the response time will be:

Scope

1, 8, 64

1

Returns

0x08

0x01..0x64

Put

Get

2

1

0x01..0x64

n/a

5 x 500us x 64 = 160ms

Section 2.4, p. 6

The second byte must be one of the following values (shown

in decimal):

Ctrl-H. In Put mode, sets the rate of drift compensation used

in the negative signal direction.

0

1

2

3

5

20 32 45 60 90 123 175 255

7

10 15

The second byte must be one of the following valid values

(shown in decimal):

Values other than the above will be rounded down.

1

15

2

20

3

25

4

33

6

45

8

60

10 12

75 100

In Get mode, the command will return a single byte according

to the rules of Section 5.2, page 21.

Values other than the above will be rounded down.

This setup can be used as a noise filter, or as a mechanism

to intentionally slow down key reaction time in order to require

a long user touch.

These numbers correspond to the amount of drift

compensation applied, in 100ms/count of reference change,

for signals which are negative with respect to the reference

level, i.e. in the same direction as legitimate detections.

Higher numbers equate to slower drift compensation.

Overcompensation (too fast) can result in the suppression of

legitimate detections. Under-compensation can result in

inadequate compensation for rapid environmental changes.

Values of 15 to 45 (1.5 to 4.5 secs/count) are considered

normal under most conditions.

Special condition: If the value for ^J is set to zero the key is

disabled, but the burst for the key is still generated.

^K 0x0B - POSITIVE

R

ECALIBRATION

D

Bytes / Cmd Byte 2 Range

ELAY

Scope

1, 8, 64

1

Returns

0x0B

0x00..0xFF

Put

Get

2

1

0x00..0xFF

n/a

Drift compensation does not occur while the signal has

passed below the ^A threshold level or subsequently

remained below the negative hysteresis level.

Section 2.7, p. 7

Ctrl-K. In Put mode, sets the delay until recalibration, timed

from when the signal first crosses the positive threshold. The

default is 0x0A (1 sec).

In Get mode, the command will return a single byte according

to the rules of Section 5.2, page 21.

The second byte controls the delay in 100ms increments, and

must be one of the following valid values:

Put mode scope can be one key, a row or column, or all keys.

0

1

2

3

5

20 32 45 60 90 123 175 255

7

10 15

^I 0

X

09 - POSITIVE

D

RIFT

C

Bytes / Cmd Byte 2 Range

OMPENSATION

R

ATE

Scope

1, 8, 64

1

Returns

0x09

0x01..0x64

Values other than the above will be rounded down. As an

example, a value of 85 will cause a 6-second delay.

Put

Get

2

1

0x01..0x64

n/a

In Get mode, the command will return a single byte according

to the rules of Section 5.2, page 21.

Section 2.4, p. 6

Ctrl-I. Same as ^H above in all respects, except operates

only when the signal is positive with respect to the reference

level, i.e. in an abnormal direction. It is usually desirable to

set this rate much faster than for ^H, i.e. to a lower number.

Valid decimal values are:

Special condition: If ^K is set to zero this feature is disabled

and the key will never auto-recalibrate on positive transitions;

however drift compensation will still operate.

^L 0x0C - NEGATIVE

R

ECALIBRATION

D

Bytes / Cmd Byte 2 Range

ELAY

1

15

2

20

3

25

4

33

6

45

8

60

10 12

75 100

Scope

1, 8, 64

1

Returns

0x0C

0x00..0xFF

Put

Get

2

1

0x00..0xFF

n/a

Values other than the above will be rounded down.

Values of 4 to 10 (0.4 to 1.0 secs/count) are considered

suitable for most systems.

Section 2.5, p. 6

Ctrl-L. In Put mode, sets the delay until recalibration, timed

from when the signal first crosses below the negative

threshold as defined by ^A. The default is 0x3C (9 secs).

Positive drift compensation continues to operate even if the

signal has exceeded the positive threshold.

The second byte represents the delay in 100ms increments,

and must be one of the following valid values:

^J 0x0A - DETECT

I

NTEGRATOR

L

Bytes / Cmd Byte 2 Range

IMIT

Scope

1, 8, 64

1

Returns

0x0A

0x00..0xFF

0

1

2

3

5

20 32 45 60 90 123 175 255

7

10 15

Put

Get

2

1

0x00..0xFF

n/a

Values other than the above will be rounded down. As an

example, a setting of 85 will cause a 6 second delay.

Section 2.6, p. 7

Ctrl-J. In Put mode, sets the detect integrator limit for one or

more keys according to scope.

In Get mode, the command will return a single byte according

to the rules of Section 5.2, page 21.

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Special condition: If the value for ^L is set to zero this Special condition: If the value is set to zero, this feature is

feature is disabled and the key will never auto-recalibrate

after a prolonged touch.

disabled.

^O 0x0F - NEGATIVE

R

EFERENCE

E

RROR

B

Bytes / Cmd Byte 2 Range

AND

^M 0x0D - INTRA-BURST

P

ULSE

S

Bytes / Cmd Byte 2 Range

PACING

Scope

64

Returns

0x0F

0x00..0x63

Scope

64

Returns

0x0D

0x02..0x0A

Put

Get

2

1

0x00..0x63

n/a

Put

Get

2

1

0x02..0x0A

n/a

Section 2.8, p. 7

Section 3.7, p. 12

Ctrl-O. In Put mode, sets the amount of tolerable negative

deviation in the reference level for all keys, in percent with

regard to the 'locked' reference value for each key. The setup

is global in nature and affects all keys equally.

Ctrl-M. In Put mode, sets the amount of time between

individual pulses in a burst.

The second byte must be in the range of 2 to 10 decimal;

other values will be ignored. The setting applies to all keys.

Valid values are from 0 to 99 decimal; higher values will be

truncated to 99. The percentage applied is equal to the

decimal value; a value of 99 equates to 99% of the signal

level (i.e. a 1% decrease w.r.t. the locked reference level).

The value corresponds to the timing between pulses within a

burst, in microseconds. For example, a setting of 5 will set the

pulse spacing to 5 microseconds.

In Get mode the function returns the current setting of ^M.

In Get mode the function returns the current value of ^M.

This setup is identical in nature to ^N except that: (1) it

governs negative reference deviations, and (2) values are

expressed in percent instead of 10's of percent.

Intra-burst pulse spacing controls the fundamental frequency

of the burst and can have a strong effect on radiated

emissions from the matrix control panel. It can also have an

effect on susceptibility to external EMI if the external fields are Special condition: If the value is set to 0, this feature is

close in periodicity to the burst spacing.

^N 0x0E - POSITIVE

disabled.

R

EFERENCE

E

RROR

B

Bytes / Cmd Byte 2 Range

AND

^P 0x10 - ADJACENT

K

EY

SUPPRESSION (‘AKS’)

Bytes / Cmd Byte 2 Range

Scope

64

Returns

0x0E

0x00..0x64

Scope

1, 8, 64

1

Returns

0x10

0x00, 0x01

Put

Get

2

1

0x00..0x64

n/a

Put

Get

2

1

0x00, 0x01

n/a

Section 2.8, p. 7

Section 2.9, p. 8

Ctrl-N. In Put mode, sets the amount of tolerable positive

deviation in the reference level for all keys, in percent, with

regard to the 'locked' reference value for each key. The setup

is global in nature and affects all keys equally.

Ctrl-P. In Put mode, instructs logic for the keys specified by

the current scope whether or not to enable the AKS feature.

Valid 2nd byte values for this function are:

0: AKS off {default}

1: AKS on

Valid values are from 0 to 100 decimal; higher values will be

truncated to 100. The percentage applied is 10x the decimal

value, thus, a value of 100 equates to a 1,000% change (i.e.

10x the locked reference level).

In Get mode, the command will return a single byte according

to the rules of Section 5.2, page 21.

In Get mode the function returns the current setting of ^N.

AKS functions to suppress detections from water films which

can 'spread' a touch signal from the touched key to adjacent

keys. It is also useful for panels with tightly spaced keys,

where a fingertip can partially overlap an adjacent key. This

feature will act to suppress the signals from the unintended

keys.

This setup is used to define the limit of possible positive

reference deviation with respect to a factory setting, which is

used in turn to set an error flag for key(s) whose reference

level rises above the designated error band. If for example

this setting is set to 50, and the device is calibrated and

reference levels are locked (see command 'L', Lock

Reference Levels) into the part by the OEM, then in the future

if the reference level of a key should rise 500% over its

Locked reference level then the key will report back an error

flag via commands 'e' or 'E'.

AKS only operates across keys that have been AKS-enabled;

signal strength comparisons are not made with non-

AKS-enabled keys.

Unused keys with burst lengths of zero are also ignored for

purposes of AKS.

To obtain the error flag for a boundary condition, the key must

be first recalibrated using the 'b' command.

The host device should periodically check the reference

levels for keys to make sure they do not rise above 191 or fall

below 64 (see Section 2.11); if this should happen the host

should recalibrate the affected key(s). Failure to do so will

prevent the error band limits from operating.

The error band can be used to detect circuit faults as well as

extremes of temperature or moisture on the circuitry. Typical

values are from 2 to 4 (20% to 40%).

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Due to the large number of bytes written to eeprom by this

5.5 Supervisory / System Functions

Supervisory functions report or control miscellaneous

functions that affect overall chip control, testing, or

diagnostics. All supervisory functions ignore scope except

where noted.

command, there is a significant delay from the second byte

until the return echo is sent back to the host.

This command should be used only during production. There

is no get version of the command.

For commands requiring Put mode to operate, the device

should be set back to Get mode immediately thereafter where

possible, to help prevent unintended writes to eeprom.

b

0x62 - RECALIBRATE

K

Bytes / Cmd 2nd Byte Range

EYS

Scope

1, 8, 64

n/a

Returns

0x62

n/a

Put

Get

1

n/a

6

0

X

36 - EEPROM

CHECKSUM

Bytes / Cmd # Bytes Rtnd

Scope

n/a

Returns

n/a

0x00..0xFF

Section 2.10, p. 8; Section 3.16

Put

Get

n/a

1

n/a

1

Lowercase 'B'. This is a put-only command that causes the

keys selected by scope to recalibrate. The part must be in Put

mode for this command to work.

See page 22.

44 - DAC TEST

The return byte is sent before the keys have calibrated. While

keys are in recalibration, status of the keys can be

determined using the 'e' or 'E' commands.

D

0

X

Scope

n/a

Bytes / Cmd 2nd Byte Range

0x00..0xFF

n/a

Returns

0x44

n/a

Put

Get

2

n/a

If 'b' is sent while key(s) are already in the middle of

recalibration, the affected key(s) will abandon the old

calibration cycle and start a new one.

Uppercase 'D'. Enables the DAC test mode function. The

second byte contains the value to be sent to the DAC, which

must be sent within 100ms to the part otherwise the

command is automatically cancelled. The part must be in Put

mode for this command to work.

There is no get version of the command.

l

0x6C - RETURN

Scope

L

AST

C

Bytes / Cmd

OMMAND

C

# Bytes Rtnd

HARACTER

Returns

n/a

0x00..0xFF

Put

Get

n/a

1

n/a

1

This function can be used to test the external R2R DAC for

proper operation during board production or in development.

Once in this mode the part ceases to operate as a sensor,

and must be reset via power-down or the reset pin to restore

normal operation. This function does not persist past reset or

power-down.

Lowercase 'L'. This get-only command reports back with the

value of the prior command received by the part. The

command also reports back any erroneous commands,

allowing the host device to verify that a command was

correctly received.

Before the DAC value is set in hardware, the burst length on

all keys is set to 0 to disable keys and prevent further

scanning. All keys will then report errors until all burst lengths

are again set by the host after the part has been reset.

If this command is repeated, the second and subsequent

instances of 'l' will report back with 0x6C.

There is no put version of the command.

A series of 'D' commands can be sent to cause the DAC to

generate a ramp or other test pattern which can be easily

diagnosed on an oscilloscope.

r

0x72 - RESET

Scope

D

EVICE

Bytes / Cmd 2nd Byte Range

Returns

0x72

n/a

There is no get version of the command.

Put

Get

n/a

2

n/a

0x00

n/a

L

0x4C - LOCK

Scope

R

EFERENCE

L

Bytes / Cmd 2nd Byte Range

EVELS

Section 3.14, p. 14

Returns

0x4C

n/a

Put

Get

64

n/a

2

n/a

0x00

n/a

Lowercase 'R'. This put-only command hard-resets the part.

The command 0x72 must be followed by a null (0x00) within

100ms or the command will fail. The part must be in Put

mode for this command to work.

Section 2.8, p. 7

Uppercase 'L'. This is a put-only command that locks the

reference levels of the device into eeprom for all keys, for

boundary checking purposes over the product's life.

After the null byte is received, the device will echo back the ‘r’

character; about 16ms after the echo the part will reset.

Upon waking up again, the part will resume communication

and sensing in accordance with the timing shown in Section

3.16.

The whole command – 'L' followed by a null (0x00) - must be

received within 100ms without any intervening byte, or the

command will fail. The part must be in Put mode for this

command to work.

If for some reason the device is unable to echo back the ‘r’

character, for example due to the host not releasing the SS

line, the part will completely reset anyway after about 2

seconds.

The scope of this command is always 'all keys'.

This function records to eeprom the Cz values, DAC offset,

and signal reference. The locked reference levels are used to

compute boundary checks; these are performed after the next

device recalibration or reset.

There is no get version of the command.

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Note that when the part is in Slave mode, the host can clock

V

0x56 - RETURN

P

ART

V

Bytes / Cmd

ERSION

data to the device at rates up to 1.5MHz even if the setting of

^Q is slower.

Scope

# Bytes Rtnd

Returns

n/a

0x00..0xFF

Put

Get

n/a

1

n/a

1

New settings do not become effective until the device has

been powered off and back on again or after the reset (‘r’)

command.

Uppercase 'V'. This get-only command returns the part

version number.

Refer to Sections 4.3 and 4.4 for specific timing details.

There is no put version of the command.

^R

0

X

12 - OSCILLOSCOPE

S

Bytes / Cmd 2nd Byte Range

YNC

W

0x57 - RETURN

P

ART

S

Scope Bytes / Cmd # Bytes Rtnd

IGNATURE

Scope

1, 8, 64

Returns

0x12

0x00, 0x01

Returns

n/a

0x20, 0x30, 0x40

Put

Get

2

1

0x00, 0x01

n/a

Put

Get

n/a

1

n/a

1

Section 3.20, p. 15

Section 3.1, p. 9

Ctrl-R. In Put mode, controls the oscilloscope sync function

of Pin 37. The settings of this function are:

Uppercase 'W'. This get-only command returns the part

signature as follows:

0: off {factory default}

1: on

0x20

0x30

0x40

(32 decimal) - for QT60325B

(48 decimal) - for QT60485B

(64 decimal) - for QT60645B

When on, Pin 37 outputs a pulse that brackets the acquire

burst(s) for the keys targeted by scope. Without this it is

virtually impossible to view signals corresponding to a specific

key.

There is no put version of this command.

Z

0x5A - ENTER

Scope

SLEEP

Bytes / Cmd 2nd Byte Range

Pin 37 idles low and pulses high during a sync pulse. Pin 37

is also used for SPI mode selection by connecting to +5 or

Ground, and as a result if ^R is used, Pin 37 should never

be clamped to a supply rail but rather connected via a 10K

resistor to prevent a short circuit. See Section 3.20.

Returns

*0x5A, 0x5A

n/a

Put

Get

n/a

2

n/a

0x00

n/a

Section 3.17, p. 14

Uppercase 'Z'. This put-only command forces the device to

enter sleep mode. The command 0x5A must be followed only

by a null (0x00) within 100ms or the command will fail.

^R is volatile, that is, it does not persist after a power down.

^S 0x13 - C

S

C

LAMP

P

Bytes / Cmd 2nd Byte Range

OLARITY

Scope

Returns

0x13

0x00, 0x01

The command returns 0x5A immediately before going to

sleep, and a second 0x5A upon waking up. The part must be

in Put mode for this command to work.

Put

Get

-

2

1

0x00, 0x01

n/a

If for some reason the device is unable to echo back the first

‘Z’ character, for example due to the host not releasing the

SS line, the part will completely reset after about 2 seconds.

Section 3.19, p. 15

Ctrl-S. Controls the polarity of the Cs Clamp line, CSR, pin

35, using the 2nd byte as follows:

The part will reawaken after a logic low is detected for >10µs

on pin 11 (X2WS pin, see Section 3.17, p. 14). The device

then sends the second ‘Z’ back to the host, and resumes

from its prior state before it went to sleep without the need for

recalibration.

0: active-low

1: active-high

The part must be in Put mode for this command to work.

This pin controls the polarity of the reset signal applied to the

charge integrator reset switch. In systems using an n-channel

switch (active-high required to reset the Cs capacitor), this

option should be set to ‘1’; for a p-channel mosfet switch in

bipolar supply systems requiring an active-low to reset the Cs

capacitor, ^S should be set to ‘0’. For the reference circuit of

Figure 3-1 this should be set to ‘0’ (the default); for the circuit

of Figure 3-2 this should be set to ‘1’..

The device always reawakens in Get mode.

There is no get version of the ‘Z’ command.

^Q 0x11 - DATA

Scope

R

ATE

S

Bytes / Cmd 2nd Byte Range

ELECTION

Returns

0x11

0x00..0x03

Put

Get

n/a

2

1

0x00..0x03

n/a

The setting of ^S does not become effective until the device

has been powered off and back on again or after the reset

(‘r’) command has been issued.

Section 4, p. 16

Ctrl-Q. This command sets the communications clock rate of

the SPI interface in Master mode. The acceptable values of

the 2nd byte are:

0: 46.875 kHz {factory default}

1: 93.75 kHz

2: 375 kHz

3: 1.5 MHz

The part must be in Put mode for this command to work.

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^T 0x14 - BOUNDARY

E

Bytes / Cmd Byte 2 Range

QN

C

ONSTANT C1, MSB

^W 0x17 - NOISE

Scope

SYNC

Bytes / Cmd Byte 2 Range

Scope

64

Returns

0x14

0x00..0x7F

Returns

0x17

0x00, 0x01

Put

Get

2

1

0x00..0x7F

n/a

Put

Get

-

2

1

0x00, 0x01

n/a

Section 2.8, p. 7

Section 3.17, p. 14

Ctrl-T. In Put mode, sets the MSB of equation constant C1

for boundary checking purposes. The part must be in Put

mode for this command to work.

Ctrl-W. In Put mode, sets whether the noise sync feature is

enabled or disabled. The part must be in Put mode for this

command to work.

The function has global scope. The default value is 5, which

corresponds to the reference circuit on page 10. A change in

this parameter only has effect after a reset or recalibration of

all keys.

The settings are:

0: off {factory default}

1: on

This function has global scope. The default value is 0 (off).

Valid values are from 0 to 127 decimal. Each count of the

MSB has a value 256x that of the LSB.

This feature can be used to synchronize the part to an

external repetitive source of e-field which might interfere with

the sensor signals, for example 50 or 60Hz fields from

adjacent power wiring. By doing so the part becomes immune

to the noise source.

In Get mode this function returns the current ^T value.

Refer to ^U (0x15) for the LSB definition.

^U 0x15 - BOUNDARY

E

QN

C

Bytes / Cmd Byte 2 Range

ONSTANT C1, LSB

In Get mode this function returns the current setting of ^W.

Scope

64

Returns

0x15

0x00..0xFF

The setting of ^W does not become effective until the device

has been powered off and back on again or after the reset

(‘r’) command has been issued.

Put

Get

2

1

0x00..0xFF

n/a

Section 2.8, p. 7

Ctrl-U. In Put mode, sets the LSB of equation constant C1 for

boundary checking purposes. The part must be in Put mode

for this command to work.

The function has global scope. The default value is 0xE9,

which corresponds to the reference circuit on page 10. A

change in this parameter only has effect after a reset or

recalibration of all keys.

Valid values are from 0 to 255 decimal. The value of the LSB

must be combined with the value of the MSB to form the total

value.

In Get mode this function returns the current ^U value.

Refer to ^T (0x14) for the MSB definition.

^V 0x16 - BOUNDARY

E

QUATION

CONSTANT C2

Bytes / Cmd Byte 2 Range

Scope

64

Returns

0x16

0x00..0xFF

Put

Get

2

1

0x00..0xFF

n/a

Section 2.8, p. 7

Ctrl-V. In Put mode, sets equation constant C2 for boundary

checking purposes. The part must be in Put mode for this

command to work.

This function has global scope. The default value is 8, which

corresponds to the reference circuit on page 10. A change in

this parameter only has effect after a reset or recalibration of

all keys.

Valid values are from 0 to 255 decimal.

In Get mode this function returns the current ^V value.

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processing time. When this happens, burst timing and host

communications can slow down and become erratic.

5.7 Timing Limitations

The device requires processing time between bursts, as well

as time to handle communications with the host. With short

burst spacings, long burst lengths, and long intra-burst pulse

spacings, the device can simply run out of available

Burst spacings should be verified on an oscilloscope during

development to be certain that the device timings are

preserved and are constant. If not, the burst length and/or

pulse spacing should be reduced.

Table 5-2 Permissible Burst Lengths (BL’s)

Pulse Spacing = 2µs

Pulse Spacing = 3µs

Pulse Spacing = 4µs

Pulse Spacing = 5µs

Pulse Spacing = 6µs

Burst

Max BL

Spacing

Burst

Max BL

Spacing

Burst

Max BL

Spacing

Burst

Max BL

Spacing

Burst

Max BL

Spacing

250

300

25

50

64

250

300

10

20

40

64

250

300

10

20

40

64

250

300

10

20

40

50

64

250

300

7

15

30

50

64

400

500

1,000

2,000

1,000

2,000

1,000

2,000

1,000

2,000

1,000

2,000

Pulse Spacing = 7µs

Pulse Spacing = 8µs

Pulse Spacing = 9µs

Pulse Spacing = 10µs

Burst

Max BL

Spacing

Burst

Max BL

Spacing

Burst

Max BL

Spacing

Burst

Max BL

Spacing

250

300

7

250

300

7

250

300

7

250

300

5

15

30

40

50

64

12

25

30

50

64

12

20

30

40

64

10

20

30

40

64

400

500

1,000

2,000

1,000

2,000

1,000

2,000

1,000

2,000

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www.qprox.com QT60xx5B / R1.06

6 PLD Source Listing

Pre-programmed parts are available from Quantum in small quantities.

The object code file for this PLD is also available upon request.

TITLE 'E664SPI'

Description

Timing skew generator for E664SPI matrix board. Code is for ICT PEEL22CV10AZ epld. Not warranted to work with any other part.

Compiler and documentation from the ICT web site, www.ictpld.com.

Programmer from System General; model “All Writer”, www.systemgeneral.com.

End_Desc;

PEEL22CV10A

"I/O CONFIGURATION DECLARATION

"IOC (PIN_NO 'PIN_NAME' POLARITY OUTPUT_TYPE FEEDBACK_TYPE)

"Inputs

Y0 PIN 5 "pre-decoded Y inputs

Y1 PIN 4

Y2 PIN 3

Y3 PIN 2

Y4 PIN 8

Y5 PIN 9

Y6 PIN 10

Y7 PIN 11

XS PIN 1 "Sum of X1..X7

X7 PIN 6 "X7 input (gets OR'd with XS)

YG PIN 7 "Y gate trigger

"Outputs

"Clamping outputs

IOC ( 21 'YM0'

IOC ( 19 'YM1'

IOC ( 17 'YM2'

IOC ( 15 'YM3'

IOC ( 16 'YM4'

IOC ( 18 'YM5'

IOC ( 20 'YM6'

IOC ( 22 'YM7'

"Dly ckt drive out

IOC ( 14 'XSD'

Pos

Com

Feed_Pin )

Pos

Com

Feed_Pin )

"QS3251 neg enable

IOC ( 23 'YGG' Pos

OutCom Feed_Pin )

AR NODE 25 "Global Asynchronous Reset

SP NODE 26 "Global Synchronous Preset

DEFINE

EQUATIONS

AR = 0;

SP = 0;

" Define Y clamp outputs

YM0.COM = 0;

YM1.COM = 0;

YM2.COM = 0;

YM3.COM = 0;

YM4.COM = 0;

YM5.COM = 0;

YM6.COM = 0;

YM7.COM = 0;

"Enable control. Goes low on active Y channel (Y= active high to clamp)

YM0.OE = Y0;

YM1.OE = Y1;

YM2.OE = Y2;

YM3.OE = Y3;

YM4.OE = Y4;

YM5.OE = Y5;

YM6.OE = Y6;

YM7.OE = Y7;

XSD.COM = 0;

XSD.OE = !(XS # X7);

"clamp the delay cap when all 'x' lines are 0

YGG.COM =!(YG & !XSD); "Enable the 3251 so long as both Yg is high AND xsd is low

"As soon as xsd goes high, disable the 3251

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7 Electrical Specifications

7.1 Absolute Maximum Specifications

Operating temp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40^OC to +105^OC

Storage temp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55^OC to +125^OC

V

DD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5 to +5.5V

Max continuous pin current, any control or drive pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mꢀ

Short circuit duration to ground, any pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . infinite

Short circuit duration to V^DD, any pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . infinite

Voltage forced onto any pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.6V to (Vdd + 0.6) Volts

Frequency of operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16MHz

Eeprom maximum writes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100,000 write cycles

Flash maximum writes (eeprom backup). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,000 write cycles

7.2 Recommended operating conditions

VDD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +4.75 to 5.25V

Supply ripple+noise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5mV p-p max

Cx transverse load capacitance per key from X to Y. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to 20pF

Fosc oscillator frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6MHz +/-2%

7.3 DC Specifications

Vdd = 5.0V, Cs = 15nF, Freq = 6.00MHz, Ta = recommended range, unless otherwise noted

Parameter

Notes

Description

Min

Typ

Max

Units

I

DDR

DDS

BOD

Supply current, running

Supply current, sleep

Brown-out detection voltage

Low input logic level

High input logic level

Low output voltage

15

mA

µA

V

Not including external components

I

20

V

4

V

IL

0.8

0.6

V

HL

2.2

V

OL

V

4mA sink

V

OH

High output voltage

Input leakage current

Acquisition resolution

Pullup resistors

Vdd-0.7

V

1mA source

I

IL

1

8

µA

bits

kohms

A

R

P

35

120

Drdy, SS’ pins

7.4 Timing

Parameter

Notes

Description

Min

Typ

Max

Units

T

DR

2

3

Tdr delay from response

Multi-byte return spacing

Host command space

SPI Clock rate

1

1,000

2,000

µS

T

15

Tcm

Fck

µS

1.5

MHz

µS

Tradc

ADC delay from R2R setup

8.16

From R2R setup to AIN+ sample

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www.qprox.com QT60xx5B / R1.06

7.5 Maximum Drdy Response Delays

... with adjacent key suppression disabled:

Burst Spacing

Function Type

Setup - put (affect 1 key)

Setup - put (affect 8 keys)

Setup - put (affect 64 keys)

Lock reference Level (L)

Calibrate command (all keys)

Get key errors (E), Get keys pushed

All other commands

250µs

300µs

10ms

400µs

500µs

10ms

1ms

10ms

40ms

300ms

800ms

4ms

2ms

10ms

40ms

300ms

800ms

4ms

10ms

40ms

10ms

40ms

300ms

800ms

4.8ms

1.8ms

800us

300ms

800ms

5.7ms

2.1ms

900us

300ms

800ms

7.6ms

2.8ms

1.2ms

300ms

800ms

9.5ms

3.5ms

1.5ms

2ms

1ms

... with adjacent key suppression enabled:

Burst Spacing

Function Type

Setup - put (affect 1 key)

Setup - put (affect 8 keys)

Setup - put (affect 64 keys)

Lock reference Level (L)

Calibrate command (all keys)

Get key errors (E), Get keys pushed

All other commands

250µs

10ms

300µs

10ms

40ms

300ms

800ms

6.6ms

3ms

400µs

10ms

40ms

300ms

800ms

8.8ms

4ms

500µs

10ms

40ms

300ms

800ms

11ms

5ms

1ms

10ms

40ms

300ms

800ms

5ms

2ms

10ms

40ms

300ms

800ms

4ms

40ms

300ms

800ms

5.5ms

2.5ms

1.5ms

2ms

1.8ms

2.4ms

3.5ms

2ms

Preliminary Data: All specifications subject to change

.

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8 Mechanical

8.1 Dimensions

A

44

42

40

38

36

34

35

43

41

39

37

1

2

3

4

5

6

7

8

9

33

32

31

30

29

28

27

26

25

24

23

p

P

L

10

11

13

15

17

19

21

20 22

12

14

16

18

a

e

o

H

h

E

Package Type: 44 Pin TQFP

Millimeters

Inches

Max

SYMBOL

Min

Max

Notes

Min

Notes

a

A

e

E

h

H

L

p

P

o

9.90

10.10

12.21

0.20

0.75

0.15

1.20

0.45

0.80

8.00

7

SQ

0.386

0.458

0.003

0.018

0.002

-

0.012

0.031

0.315

0

0.394

0.478

0.008

0.030

0.006

0.047

0.018

0.031

0.315

7

SQ

11.75

0.09

0.45

0.05

-

0.30

0.80

8.00

0

BSC

8.2 Marking

T_A

TQFP

Marking

-40⁰C to +105⁰C

QT60325B-AS

QT60485B-AS

QT60645B-AS

QT60325B-A

QT60485B-A

QT60645B-A

lQ

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www.qprox.com QT60xx5B / R1.06

9 Index

A

adc

H

hard reset, 8

hysteresis, 6, 25, 26, 32

subranging, 4, 5

adjacent key suppression, 8, 27

alert output, 15

application assistance, 5

I

intra-burst pulse spacing, 12, 27, 34

B

block diagram, 5

boundary equation, 30, 33

burst length, 8, 9, 12, 20, 24, 25, 28, 34

burst spacing, 6, 25, 34

burst timing, 9, 19

J

jfet, 13

K

key design, 5

key numbering convention, 21

key reporting, 23, 24

C

calibration, 8, 13, 14, 15, 20, 21, 28

charge cancellation, 4, 9, 22

charge gate, 9

L

ladder dac

R2R ladder, 5, 7, 9, 14

led, 15

lock reference levels, 7, 17, 28

charge integrator, 4, 5, 9, 12, 13, 29

charge neutralization, 9

circuit model, 4, 5

cs, 6, 9, 13, 15, 29

cs clamp polarity, 29

csr drive polarity, 15

cx, 4, 6, 8, 9, 21, 25

M

marking, 38

master mode, 16, 18, 19

master-slave mode, 16, 18

matrix configuration, 5

mechanical, 38

miso, 17, 18

mosi, 14, 17, 18, 19

multi-byte responses, 18, 19

cz, 5, 6, 7, 8, 9, 13, 14, 21, 28

D

dac test, 28

delta signals, 22

detect integrator, 22, 26

detection integrator, 6, 7, 22

device status, 22

device variations, 5

dimensions, 38

direction commands, 20

drdy’, 17, 18

N

negative detect integrator, 26

negative detect threshold, 12, 24

negative error band, 27

negative recalibration delay, 6, 26

negative threshold, 5, 6, 8, 12, 25, 26

noise, 12, 15, 16, 24, 26

noise coupling, 12

drift compensation, 6, 7, 8, 13, 15, 20, 23, 24, 26

dwell, 34

gate dwell, 5, 9, 12, 13, 14, 16, 25

E

O

echo, 18, 19, 24, 28

eeprom checksum, 22, 28

electrostatic shield, 15

emi, 4, 27

offset, 5, 6, 7, 8, 9, 13, 14, 21, 22, 28

opamp, 13

oscillator, 14, 16

oscilloscope sync, 15

error code, 23

Error byte, 23

error guardbanding, 7

esd protection, 16

P

pcb layout, 15

peel22cv10az, 13, 35

pld, 9, 12, 13, 14, 16, 35

positive detect threshold, 24

positive drift compensation, 26

positive error band, 27

positive recal delay, 7, 8

positive recalibration delay, 7, 26

positive threshold, 6, 7, 8, 25, 26

power supply, 15

F

fast-recalibration, 7, 8

field flow, 4

function summary table, 31

G

gate dwell

put command, 20

dwell, 5, 9, 12, 13, 14, 16, 25

get command, 20

ground plane, 15

Q

qmbtn, 4, 15, 16

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www.qprox.com QT60xx5B / R1.06

spi interface, 4

qs3251, 12, 13, 16, 35

qt60325, 9, 29

qt60485, 9, 29

spi noise problems, 16

spi rate, 29

ss’, 17, 18, 19

startup, 13, 14, 15

status commands, 20, 21

subranging

ADC, 4, 5

supervisory functions, 20, 28

sync, 14, 15, 16, 18, 22, 29, 30

R

r2r ladder

ladder DAC, 5, 7, 9, 14

recalibrate keys (command), 28

recalibration, 6, 7, 8, 13, 23, 24, 26, 28, 30

reference level, 4, 6, 7, 8, 25, 26, 27

reference levels, 22

T

reference window boundary, 8

reset, 4, 7, 8, 9, 13, 14, 15, 20, 21, 28, 29, 30, 35

resonator, 14, 15

response delays, 17, 37

return last command, 28

return part signature, 29

return part version, 29

threshold level, 6, 7, 25, 26

timing limitations, 34

tlc2272, 13

U

uart, 16

rf emissions, 5

V

S

scan sequence

Matrix scan sequence, 9

sck, 17, 18, 19

vdd, 15, 16

vee, 15

virtual ground, 4

scope, 16, 20, 21

scope commands, 21

sensitivity, 12

W

water films, 4, 14, 27

serial interface, 16

setup commands, 20, 24

signal gain, 9, 13, 25

signal levels, 4, 22

signal processing, 4, 5

slave mode, 16, 17, 18, 19

sleep mode, 14, 29

sleep_wake, 14, 15

soft reset, 8

X

x electrode drives, 9

x2ws, 14

Y

y gate drives, 12

yc0..yc7, 12

ys0..ys2, 12

spi, 4, 15, 16, 17, 18, 19, 20, 29

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www.qprox.com QT60xx5B / R1.06

Erratta / Notes

4 April 2003 - The QT60xx5 version 1.05 datasheet erroneously showed negative recalibration timeouts in the range from

1..255 seconds. The correct range is 0.1..25.5 seconds. From version 1.06 datasheet on this document change has been

made. The devices themselves are not affected.

QT60xx5B / R1.06

LQ

Patented and patents pending

Corporate Headquarters

1 Mitchell Point

Ensign Way, Hamble SO31 4RF

Great Britain

Tel: +44 (0)23 8056 5600 Fax: +44 (0)23 8045 3939

admin@qprox.com

www.qprox.com

North America

651 Holiday Drive Bldg. 5 / 300

Pittsburgh, PA 15220 USA

Tel: 412-391-7367 Fax: 412-291-1015

The specifications set out in this document are subject to change without notice. All products sold and services supplied by QRG are subject

to our Terms and Conditions of sale and supply of services which are available online at www.qprox.com and are supplied with every order

acknowledgement. QProx, QTouch, QMatrix, QLevel, and QSlide are trademarks of QRG. QRG products are not suitable for medical

(including lifesaving equipment), safety or mission critical applications or other similar purposes. Except as expressly set out in QRG's

Terms and Conditions, no licenses to patents or other intellectual property of QRG (express or implied) are granted by QRG in connection

with the sale of QRG products or provision of QRG services. QRG will not be liable for customer product design and customers are entirely

responsible for their products and applications which incorporate QRG's products.

QT60xx5B / R1.06


型号：	QT60645B
厂家：	QUANTUM RESEARCH GROUP
描述：	32, 48, 64 KEY QMatrix KEYPANEL SENSOR ICS 32 ， 48 ， 64 KEY QMatrix KEYPANEL传感器IC 传感器
文件：	总42页 (文件大小：810K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

QT60645B [QUANTUM]

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