MAX1270EVSYS [MAXIM]

Evaluation Kit/Evaluation System for the MAX1270/MAX1271/MAX127/MAX128 ; 评估板/评估系统MAX1270 / MAX1271 / MAX127 / MAX128\n


型号：	MAX1270EVSYS
厂家：	MAXIM INTEGRATED PRODUCTS
描述：	Evaluation Kit/Evaluation System for the MAX1270/MAX1271/MAX127/MAX128 评估板/评估系统MAX1270 / MAX1271 / MAX127 / MAX128\n
文件：	总7页 (文件大小：192K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

19-4782; Rev 2; 8/00

MAX1270 EV Kit/EV System

General Description

Features

The MAX1270 evaluation system (EV system) is a com-

plete, 8-channel data-acquisition system, consisting of a

MAX1270 evaluation kit (EV kit) and a Maxim

68HC16MODULE-DIP microcontroller (µC) module. It is

designed to evaluate the MAX1270/MAX1271, a multi-

range, 8-channel, 12-bit data-acquisition system.

Windows 3.1™/Windows 95™ software provides a handy

user-interface to exercise the MAX1270’s features.

ꢀ Proven PC Board Layout

ꢀ Complete Evaluation System Samples to 12ksps

ꢀ Convenient Test Points Provided On-Board

ꢀ Data-Logging Software with FFT Capability

ꢀ Fully Assembled and Tested

Order the complete EV system (MAX1270EVC16) for

comprehensive evaluation of the MAX1270 or MAX1271,

using a personal computer. Order the EV kit

(MAX1270EVKIT) if you have already purchased the µC

module (68HC16MODULE-DIP) with another Maxim EV

system or for custom use in other µC-based systems.

Ordering Information

PART

TEMP. RANGE

0°C to +70°C

INTERFACE TYPE

User-Supplied

MAX1270EVKIT

MAX1270EVC16

Windows Software

The MAX1270 EV kit can also be used to evaluate the

MAX127 and MAX128.

Note: The MAX1270 software can be used only with the com-

plete evaluation system (MAX1270ECV16), which includes the

68HC16MODULE-DIP module with the MAX1270EVKIT.

Component Lists

MAX1270EVKIT Component List

DESIGNATION

QTY

DESCRIPTION

14-pin sockets

DESIGNATION

C1, C12, C13, C14

C2–C9

QTY

DESCRIPTION

U2, U3

0.1µF ceramic capacitors

0.01µF ceramic capacitors

0.01µF ceramic capacitor

4.7µF, 10V tantalum capacitors

14-pin headers with four

jumper wires

(2–3, 5–6, 9–10, 12–13)

U2, U3

C10

C11, C15

4.096V voltage reference

MAX6141BCSA

22µF, 50V aluminum

electrolytic capacitor

C16

5V at 30mA linear regulator

MAX1615EUK

Dual common-cathode

Schottky diode

None

PC board

JU1

JU2, JU3

3-pin header

2-pin headers

Software disk,

“MAX1270 Evaluation Kit”

10Ω 5ꢀ resistor

Open

R2–R5

R6–R13

R14

MAX1270EVC16 Component List

300Ω 5ꢀ resistors

1MΩ 5ꢀ resistor

8-pin header

PART

QTY

DESCRIPTION

MAX1270EVKIT

MAX1270 evaluation kit

TP1

28-pin socket, 0.300in. width

MAX1270ACNG

68HC16 µC module with

16-bit parallel interface

68HC16MODULE-DIP

Windows 3.1 and Windows 95 are trademarks of Microsoft Corp.

________________________________________________________________ Maxim Integrated Products

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

MAX1270 EV Kit/EV System

MAX1270 EV KIT Software

68HC16 Source Code Files

Windows Application Program Files

Main source code for the KIT1270.C16

program, provided for reference.

Application program that runs under

MAXADC.EXE

Window 3.1 or Windows 95

Compiled with Motorola 68HC Macro

MAX1270.HLP

MAX1270.DLL

MAXADC.INI

MAX1270.C16

Help file

KIT1270.ASM

Assembler, version 4.1. Maxim holds

the copyright but allows customers to

adapt the program for their own use

without charge.

MAXADC personality module for

MAX1270

Program settings file

Source code defining the program

interface with the Maxim 68HC16

module ROM (rev. 1)

Software loaded into 68HC16

microcontroller

EVKIT.ASM

Install/Uninstall Program Files

Source code adding enhanced services

(rev. 2) for the older Maxim 68HC16

module ROM (rev. 1)

UPGRADE1.INC

QSPI.ASM

INSTALL.EXE

Installs the EV kit files on your computer

INSTALL16.EXE

Installs the EV kit files on your computer

Removes the EV kit files from your

computer

Source code defining the program

interface with the Motorola QSPI™

(Queued Serial Peripheral Interface)

UNINST.EXE

Removes the EV kit files from your

computer

UNINST32.EXE

UNINST.INI

Source code defining the program

interface with the Motorola GPT

peripheral. Provides general-purpose

I/O pins.

Database for uninstall program

GPT.ASM

Windows program information file for

uninstall

UN-MAXIM.PIF

Evaluating the MAX127/MAX128

The MAX1270 EV board may be used to evaluate the

MAX127 or MAX128 with a user-supplied, 2-wire con-

troller and software. Replace U1 with the MAX127ACNG

or MAX128ACNG. Cut the default trace on the back of

the board under JU1 (marked with an arrow). Short pins 1

and 2 of jumper JU1. Connect your two-wire interface to

SCL, SDA, and GND. Install 100Ω resistors at R2, R3, R4,

and R5. With the address select pins pulled down by R3,

R4, and R5, the two-wire device address is 01010000 for

writing commands to the part and 01010001 for reading

data from the part. Refer to the MAX127 data sheet for

waveforms and timing requirements.

MAX1270 Evaluation System

The MAX1270 EV system operates from a user-sup-

plied +8V to +12V DC power supply. Windows 3.1/95

software running on an IBM PC interfaces to the EV sys-

tem board through the computer’s serial-communica-

tions port. The software can be operated with or without

a mouse. Refer to the Quick Start section for setup and

operating instructions.

MAX1270/MAX1271

Stand-Alone EV Kit

The MAX1270 EV kit provides a proven PC board layout

to facilitate evaluation of the MAX1270. Apply your sys-

tem’s 12V power-supply rails to the OPAMP+ and

OPAMP- terminals. Connect GND to your system

ground return. The OPAMP+ input powers a MAX1615

linear regulator and a MAX6141 voltage reference. It

must be interfaced to appropriate timing signals for

proper operation.

Note: The MAX1270 EV system software does not

support the MAX127 or MAX128.

Quick Start

Recommended Equipment

Connect your three-wire interface to SCLK, DIN, DOUT,

and GND. Leave R3 and R4 open. If you do not drive

CS, install a 100Ω resistor at R5. If you do not drive

SHDN, install a 100Ω resistor at R2. Make sure JU1 is in

position 2-3 (factory setting). Refer to the MAX1270

data sheet for waveforms and timing requirements.

You will need the following equipment before you

begin:

• A small DC power supply, +8V to +12V at 200mA

QSPI is a trademark of Motorola Corp.

_______________________________________________________________________________________

MAX1270 EV Kit/EV System

• An IBM PC-compatible computer running Windows

Using Op Amp Buffers

Applications measuring high-impedance sources may

require buffers to ensure full measurement accuracy.

The MAX1270EVKIT can be used with optional user-

supplied quad op amp buffers. Simply unplug the 14-

pin headers at U2 and U3 and install a suitable unity-

gain-stable quad op amp.

3.1 or Windows 95

• A spare serial communications port, preferably a

9-pin plug

• A serial cable to connect the computer’s serial port to

the Maxim 68HC16MODULE-DIP module

Procedure

1) Carefully connect the boards by aligning the 40-pin

header of the MAX1270 EV kit with the 40-pin con-

nector of the 68HC16MODULE-DIP module. Gently

press them together. The two boards should be

flush against one another.

Detailed Description

of Software

The various program functions are grouped into dialog

boxes that are accessible from the Window menu on

the main menu bar.

2) Connect an +8V to +12V DC-power source to the

µC module at terminal block J2, located next to the

ON/OFF switch, along the top edge of the µC mod-

ule. Observe the polarity marked on the board.

Keyboard Navigation

If a mouse or other pointing device is not available,

operate the program using the following keyboard

shortcuts.

3) Connect a cable from the computer’s serial port to

the µC module. If using a 9-pin serial port, use a

straight-through, 9-pin female-to-male cable. If the

only available serial port uses a 25-pin connector, a

standard 25-pin to 9-pin adapter is required. The

EV kit software checks the modem status lines

(CTS, DSR, DCD) to confirm that the correct port

has been selected.

• Press ALT+W to bring up the Window menu and then

select a tool window.

• Press the TAB key to select controls within the select-

ed tool window.

• Activate buttons by pressing the space bar.

• Use the up/down arrow keys for check boxes, radio

buttons, and combo boxes.

4) Install the software on your computer by running the

INSTALL.EXE program on the floppy disk. The pro-

gram files are copied and icons are created in the

Windows 3.1 Program Manager (or the Windows 95

Start Menu). The EV kit software evaluates both the

MAX1270 and the MAX1271.

Scan Tool

You can take readings automatically from selected

channels at regular intervals up to 10 samples per sec-

ond by selecting Scan Tool from the Window menu. The

Channel Selection and Configuration group controls

which channels will be scanned.

5) Start the MAX1270 program by opening its icon in

the Program Manager (or Start Menu).

The Scan-Rate combo box controls the rate at which

measurements are made. Readings are displayed in

the Recent Values text area.

6) The program will prompt you to connect the µC

module and turn its power on. Slide SW1 to the

“ON” position. Select the correct serial port, and

click OK. The program will automatically download

KIT1270.C16 to the module.

Table 1. Keyboard Navigation Shortcuts

When the software successfully establishes com-

munication with the EV kit board, you will see a

Device Characteristics Tool and some other win-

dows. The default device setting is for the

MAX1270. If you are using the MAX1271, select

MAX1271 in the Device Characteristics dialog box,

and click the Apply button.

KEY

FUNCTION

TAB

Select next control

ALT + W

Window menu

ALT + space

ALT + minus

Space Bar

System menu of main program window

System menu of child window

Click on the selected button

7) Apply input signals to the inputs labeled CH0–CH7,

at the right edge of the MAX1270 EV kit board.

Observe the readout on the screen.

Copy the image of main window onto

the clipboard

ALT + Print Screen

_______________________________________________________________________________________

MAX1270 EV Kit/EV System

External-Clock Mode

Low-Speed Data Logging

To operate in external-clock mode (18 clocks per con-

version), select External Clock from the list of choices

under Power-Up Mode.

You may optionally record readings into a data log file.

Click on the New Log button to begin or end data log-

ging. The Log File Format dialog box is displayed. One

complete line of data is written after all enabled chan-

nels have been sampled. The first line of the log file

contains the column headings. Each subsequent line

contains all enabled channels, separated by commas,

tabs, or spaces (previously selected in the Log File

Format dialog box). Once a log file has been opened, it

can be paused or resumed with the Pause button. The

program continues to write data to the log file until the

Stop Log button is clicked.

Sampling Tool

To sample data at rates up to 12ksps (samples per

second), select Sampling Tool from the Window menu,

make your selections, and click on the Start button.

Adjust the timing delays as appropriate to control the

sample rate. Estimate the effective sample rate by tak-

ing the reciprocal of the sum of the delay between sam-

ples, the power-up delay, and the conversion time.

Sample size is restricted to a power of two, so that the

Fast Fourier Transform Tool (FFT) can process the data.

Sample Size controls the number of samples collected

on each selected channel. After the samples have been

collected, the data automatically uploads to the host

and is graphed. Once displayed, the data can be

saved to a file.

One-Shot Read Tool

The One-Shot Read Tool allows direct control of the A/D

configuration. Select the channel and mode of opera-

tion to update the Control Byte display, or change indi-

vidual bits within the Control Byte directly, and observe

the change in the channel selection control. The Read

Now button writes the configuration information to the

A/D and performs one reading.

FFT Tool

The MAX1270 evaluation software includes an FFT Tool

that can display the spectral content of data collected

with the Sampling Tool.

Power-Cycling Tool

When using its internal reference, the MAX1270 can be

shut down between measurements to reduce average

supply-current demand. From the Window menu, select

Power-Cycling Tool. The amount of power savings

depends primarily on how long the part is off between

conversions. The accuracy of the conversions depends

on the power-up delay, the reference capacitor, and

the time in power-down. Adjust the off-time with the

Delay-Between-Samples command. Adjust the on-time

with the Power-Up Delay command.

To view the spectral content of a waveform, first select

a data sample that was previously collected with the

Sampling Tool, then select FFT Tool from the Window

menu. Check the output plots desired, and click on the

Start button.

A data-windowing function preprocesses the data sam-

ple before performing an FFT. When the input signal is

not synchronized to the sampling clock, spectral ener-

gy appears to leak into nearby frequency bins. A suit-

able data window tapers the raw data to zero amplitude

at the beginning and end, reducing the spectral energy

leak. For more information on the Fast Fourier

Transform and data-windowing functions, refer to W. H.

Press, et al., Numerical Recipes in Pascal: The Art of

Scientific Computing, Cambridge University Press,

1989, ISBN 0-521-37516-9.

Using an adequate power-up delay will ensure the

desired conversion accuracy during power-cycling

modes. The reference must be allowed enough time to

stabilize before the measurement is performed. Start

with zero Power-Up Delay and increase the delay time

until no further change in accuracy is observed. The

power-up delay requirement depends on the value of

the reference capacitor and the off-time (delay between

samples).

Noise-Analysis Tool

The evaluation software includes a Noise-Analysis Tool

that calculates some statistics of data collected with the

Sampling Tool.

The MAX1270 EV kit software performs power-up by

writing a configuration selecting standby mode. After

powering-up, the power-up delay is executed to allow

time for the reference voltage to stabilize for an accu-

rate measurement.

To view a statistical analysis, first select a data sample

previously collected with the Sampling Tool, then select

Noise-Analysis Tool from the Window menu.

Internal-Clock Mode

To operate in internal-clock mode (13 clocks per con-

version), select Internal Clock from the list of choices

under Power-Up Mode.

Minimum and maximum values are the smallest and

largest values that occur in the data record. Peak-to-

peak voltage is calculated as the difference between

minimum and maximum values.

_______________________________________________________________________________________

MAX1270 EV Kit/EV System

Average value is the arithmetic mean; i.e., the sum of all

values divided by the number of samples. Standard

deviation is used as an approximation to RMS voltage.

Table 2. Jumper Functions

JUMPER STATE

FUNCTION

U1 = MAX127 or MAX128. Use 2-wire

interface signals on TP1 test points.

Device Characteristics

The Device Characteristics dialog box is used to select

between the MAX1270 and MAX1271.

1-2

U1 = MAX1270 or MAX1271. Use

3-wire interface signals on TP1 test

points, or use 68HC16 module and

supplied software.

JU1

2-3*

Evaluating the MAX1271

The MAX1270 software can evaluate the MAX1271

directly. From the Window menu, pick Device

Characteristics. Next, change the device type from

MAX1270 to MAX1271 and click the Apply button. This

Enable U1’s internal reference. JU3

must be open.

Open

JU2

tells the program that the input voltage span is

instead of 10V.

REF

Disable U1’s internal reference. Refer to

Table 3, Voltage Reference Truth Table.

Closed*

Changing the Reference Voltage

The MAX1270 EV kit software assumes a 4.096V refer-

ence voltage, unless otherwise specified by the user. To

If JU2 is open, selects internal

reference. If JU2 is closed, user must

provide reference at VREF input pad.

Refer to Table 3, Voltage Reference

Truth Table.

Open

JU3

use the on-board MAX6141 reference (V

= 4.096V)

REF

close JU2 and JU3. For an external, user-supplied refer-

ence, close JU2, open JU3, and apply the reference to

the V

pad. To use the internal reference, open JU2

REF

Use voltage reference U4. Jumper JU2

must be closed.

and JU3. See the MAX1270 data sheet for more infor-

mation. From the Window menu, select Device

Characteristics, then type the new reference voltage

into the Reference Voltage edit box.

Closed*

Table 3. Voltage Reference Truth Table

Detailed Description

of Hardware

JU2

Open

Closed

JU3

FUNCTION

Open

Enable U1’s internal reference

U1 is a MAX1270/MAX1271/MAX127/MAX128 analog-

to-digital converter. C10 bypasses the internal

bandgap reference, and C11 bypasses the 4.096 volt

reference output. Sockets U2 and U3 accommodate

optional unity-gain-stable quad op amp buffers. C2–C9

and R6–R13 form anti-aliasing input filters for the eight

input channels. U4 is an optional MAX6141 external ref-

erence. U5 is a linear regulator that provides +5V to U1

when used in stand-alone mode.

Closed Invalid operating configuration

User must provide a reference at the

Open

Closed Closed Use voltage reference U4

Troubleshooting

Problem: No output measurement. System seems to

report zero voltage or fails to make a measurement.

• Check the +5V supply voltage. Check the buffer op-

amp supply voltages if applicable.

Measuring Supply Current

Supply current can be monitored by measuring the volt-

age across resistor R1. This resistor is 10Ω 5ꢀ, so

every 1mV across R1 represents 100µA of supply cur-

rent.

• Check the V

and REFADJ reference voltages

REF

using a digital voltmeter.

• Use an oscilloscope to verify that pin 5 (SCLK/SCL) is

receiving clock strobe pulses.

• Verify that SHDN is not being pulled low.

Problem: Erratic, unstable measurement. Use an

oscilloscope to measure:

• V

—increase reference capacitor if necessary.

REF

• SHDN—ensure that shutdown mode is not activated.

• Analog input (while triggering on DIN)—large voltage

disturbances can be cured by using an op amp

buffer (see Op Amp Buffers section).

_______________________________________________________________________________________

MAX1270 EV Kit/EV System

Figure 1. MAX1270 EV Kit Schematic

_______________________________________________________________________________________

MAX1270 EV Kit/EV System

1.0"

Figure 2. MAX1270 EV Kit Component Placement Guide—

Component Side

1.0"

Figure 3. MAX1270 EV Kit PC Board Layout—Component Side

Figure 4. MAX1270 EV Kit PC Board Layout—Solder Side

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7

Printed USA

is a registered trademark of Maxim Integrated Products.

MAX1270EVSYS [MAXIM]

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