MAX1282EVSYSTEM - Maxim Integrated Products, Inc.

General Description

The MAX1282 evaluation system (EV system) is a com-

plete four-channel data-acquisition system consisting of

a MAX1282 evaluation kit (EV kit) and a Maxim

68HC16MODULE-DIP microcontroller (µC) module. The

MAX1282 is a high-speed, 12-bit data-acquisition sys-

tem. Windows®95/98 software provides a handy user

interface to exercise the MAX1282’s features.

Order the complete EV system (MAX1282EVC16) for

comprehensive evaluation of the MAX1282 using a PC.

Order the EV kit (MAX1282EVKIT) if the 68HC16MOD-

ULE-DIP module has already been purchased with a

previous Maxim EV system, or for custom use in other

µC-based systems.

Features

♦Proven PC Board Layout

♦Convenient On-Board Test Points

♦Data-Logging Software

♦Fully Assembled and Tested

Evaluates: MAX1282

MAX1282 Evaluation System

________________________________________________________________ Maxim Integrated Products 1

19-1688; Rev 0; 8/00

For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.

For small orders, phone 1-800-835-8769.

Ordering Information

PART TEMP. RANGE INTERFACE

MAX1282EVKIT 0°C to +70°C User supplied

MAX1282EVC16 0°C to +70°C Windows software

Note: MAX1282 software is designed for use with the complete

EV system, MAX1282EVC16 (includes 68HC16MODULE-DIP

module and MAX1282EVKIT). If the MAX1282 evaluation soft-

ware will not be used, the MAX1282EVKIT board can be pur-

chased by itself, without the µC.

MAX1282EVC16 System

PART QTY DESCRIPTION

MAX1282EVKIT 1 MAX1282 EV kit

68HC16MODULE-DIP 1 68HC16 µC module

MAX1282EVKIT

Component List

MAX1282EVKIT Files

FILE DESCRIPTION

INSTALL.EXE Installs the EV kit files on your computer

MAX1282.EXE Application program

KIT1282.C16 Software loaded into 68HC16 µC

Recommended Equipment

•Maxim MAX1282EVC16 (contains MAX1282EVKIT

board and 68HC16MODULE-DIP)

•A small DC power supply, such as a 12VDC 0.25A

plug-in transformer or a 9V battery

•An IBM PC-compatible computer running Windows

95/98

•A spare serial communications port, preferably a 9-

pin plug

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

to the 68HC16MODULE-DIP

Quick Start

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

header of the MAX1282 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.

DESIGNATION QTY DESCRIPTION

C1−C4, C10 5 0.01µF ceramic capacitors

C9 1 4.7µF tantalum capacitor

C11, C13 2 0.1µF ceramic capacitors

C12, C14 2 10µF, 10V tantalum capacitors

J1 1 2x20 right-angle socket

JU1 1 2-pin header

JU2 1 3-pin header

R1−R4 4 300Ω ±5% resistors

R9, R10 2 10Ω ±1% resistors

TP1 1 8-pin header

U1 1 Maxim MAX1282BCUE (16-pin

TSSOP)

None 1 PC board, MAX1282 EV kit

None 1 3-1/2in software disk, MAX1282

None 1 MAX1282 EV kit data sheet

None 1 MAX1282 data sheet

Windows 95/98 is a registered trademark of Microsoft Corp.

2) Ensure that JU1 is closed and JU2 is in the 1-2

position (Table 1).

3) Connect a 7VDC to 20VDC power source to the µC

module at the terminal block located next to the

on/off switch, along the top edge of the µC module.

Observe the polarity marked on the board.

4) 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 will be required.

The EV kit software checks the modem status lines

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

has been selected.

5) Install the MAX1282 EV kit software on your com-

puter by running the INSTALL.EXE program on the

floppy disk. The program files are copied and icons

are created for them in the Windows Start menu.

6) Start the MAX1282 program by opening its icon in

the Start menu.

7) 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 press

OK. The program will automatically download

KIT1282.C16 to the module.

8) Apply input signal between CH0 and COM.

Observe the readout on the screen.

Detailed Description

MAX1282 Stand-Alone EV Kit

The MAX1282EVKIT provides a proven PC board layout

to evaluate the MAX1282. It must be interfaced to

appropriate timing signals for proper operation.

Connect +5V to VDD, and connect ground return to

GND (Figure 1). Refer to the MAX1282 data sheet for

timing requirements.

MAX1282 EV System

The MAX1282EVC16 EV system operates from a user-

supplied 7VDC to 20VDC power supply. Windows

95/98 software running on an IBM PC interfaces to the

EV system board through the computer’s serial commu-

nications port. See the Quick Start section for set-up

and operating instructions.

Description of Software

The evaluation software’s main window controls the ser-

ial clock speed and sample rate. It displays the voltage

and output code, as well as some input signal statis-

tics. A separate graph window shows the data chang-

ing in real time. The update rate is limited to about 10

samples per second, due to COM port bandwidth limi-

tations.

Controls

The control word is divided into several fields. To

change the active control word, drop down the appro-

priate field’s combo box and select the desired option.

If the QSPI™ clock is set to STOP, then configuration

data will not be sent until the READ button is pressed.

Statistics

The Minimum and Maximum fields show the highest

and lowest readings acquired. The Average field shows

a running mean. The Clear button resets the statistics.

To remove offset errors, first apply 0V to the active

input channel, clear statistics, acquire some samples,

and then check Tare. This average offset voltage will

now be subtracted from all subsequent measurements.

Sampling

Choose the desired sampling rate (QSPI clock), sam-

pling size (Sample! menu item), and press Begin

Sampling! (in Sample! pop-up window). Sample size is

restricted to a power of two to permit FFT processing

once the data is saved to a file. After the samples have

been collected, the data is automatically uploaded to

the host and is graphed. Once displayed, the data can

optionally be saved to a file.

Saving Graphs to Disk

Data in the real-time graph and in sampled data graphs

may be saved to a file. Only the raw output codes are

saved, but voltages may be inferred, based on the ref-

erence voltage and the maximum code value.

Scanning All Channels Input Signal

To scan through all channels, select SCAN from the

Input menu.

Evaluates: MAX1282

MAX1282 Evaluation System

2 _______________________________________________________________________________________

Table 1. Jumper Functions

JUMPER POSITION FUNCTION

Closed* COM tied to GND

JU1 Open COM must be connected to

analog common

1-2* Operate

JU2 2-3 Shutdown

*Default configuration

QSPI is a trademark of Motorola, Inc.

Evaluates: MAX1282

MAX1282 Evaluation System

_______________________________________________________________________________________ 3

Evaluating Shutdown

The evaluation software configures the 68HC16’s QSPI

submodule to continuously read data from the

MAX1282 into the 68HC16. The sample rate is con-

trolled by the QSPI clock. To evaluate power-saving

modes, these automatic updates must be stopped.

First, set the QSPI clock control to STOP. This reconfig-

ures the 68HC16’s QSPI submodule to stop driving the

serial clock. Second, in the evaluation software’s main

window, uncheck the Read Every...msec check-box.

Next, choose the desired software power-down control

word, and press the Read button to send the new con-

figuration to the MAX1282. If evaluating the hardware

shutdown, move jumper JU2 to the 2-3 position.

Reference Voltage

The evaluation software assumes a 2.5V reference volt-

age, unless otherwise specified. Refer to the MAX1282

data sheet for more information. To override this value,

type the new reference voltage into the VREF edit box

and press the Set VREF button. Note: This new VREF

value is used only by the evaluation software and does

not physically change the reference voltage.

Detailed Hardware

Description

U1, the MAX1282, is a high-speed, multichannel, 12-bit

data-acquisition system. Resistors R1–R4 and capaci-

tors C1–C4 form single-pole, lowpass anti-aliasing fil-

ters with a nominal 3µs time constant and a corner fre-

quency of approximately 50kHz. C9 and C10 bypass

the ADC’s voltage reference and reference buffer.

When plugged into the 68HC16MODULE, the VDD cir-

cuit is powered by +5V. (See Figure 1 and refer to the

MAX1282 data sheet.)

Troubleshooting

Problem: No output measurement. System seems to

report zero voltage or fails to make a measurement.

Check the VDD supply voltage. Check the reference

voltage using a digital voltmeter (DVM). Use an oscillo-

scope to verify that the conversion-start signal is being

strobed. Verify that SHDN is being driven high.

Problem: Measurements are erratic, unstable; poor

accuracy.

Check the reference voltage using a DVM. Use an

oscilloscope to check for noise. When probing for

noise, keep the oscilloscope ground return lead as

short as possible, preferably less than 1/2in (10mm).

Evaluates: MAX1282

MAX1282 Evaluation System

4 _______________________________________________________________________________________

Figure 1. MAX1282 EV Kit Schematic

MAX1282

116

VDD1

CH0

VDD2

CH1

SCLK

CH2

CH3

DIN

SSTRB

DOUT

GND

COM

REFADJ

REF

SHDN

REFADJ

C10

0.01µF

C13

0.1µF

R10

10Ω

C14

10µF

10V

TP1-7

J1-8

VDD2

TP1-6

J1-37

TP1-4

J1-36

TP1-5

J1-31

J1-38

TP1-3

J1-29

TP1-2

J1-35

GND

TP1-1

J1-1

J1-2

J1-3

J1-4

300Ω

0.01µF

CH0

300Ω

0.01µF

CH1

300Ω

0.01µF

CH2

300Ω

0.01µF

CH3

COM

JU1 2

JU2

VDD1

SHDN

REF

4.7µF

10V

J1-7

C11

0.1µF

10Ω

C12

10µF

10V

VDD1

Evaluates: MAX1282

MAX1282 Evaluation System

_______________________________________________________________________________________ 5

Figure 2. MAX1282 EV Kit Component Placement Guide—

Component Side

Figure 3. MAX1282 EV Kit PC Board Layout—Component Side

Figure 4. MAX1282 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.

6_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

Evaluates: MAX1282

MAX1282 Evaluation System

NOTES