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19-4751; Rev 2; 7/98

MAX147 Evaluation System/Evaluation Kit

General Description

The MAX147 evaluation system (EV system) is a com-

plete, low-cost, 8-channel data-acquisition system con-

sisting of a MAX147 evaluation kit (EV kit) and a Maxim

68HC16 or 80C32 microcontroller (µC) module. IBM

PC-compatible software provides a handy user inter-

face to exercise the MAX147’s features. Source code is

provided.

Order the EV system for comprehensive evaluation of

the MAX147 using a personal computer. Order the EV

kit if the 68HC16 or 80C32 µC module was purchased

previously with another Maxim EV system, or for custom

use in other µC-based systems.

The MAX147 EV kit evaluates both the MAX147 and the

MAX146. To evaluate the MAX146, order a free sample

of the MAX146BCPP along with the MAX147 EV kit.

♦

Proven PC Board Layout

♦

Complete Evaluation System

♦

Convenient Test Points Provided On-Board

♦

Data-Logging Software

♦

Source Code Provided

♦

Fully Assembled and Tested

Features

Evaluates: MAX146/MAX147

Ordering Information

PART

MAX147EVKIT-DIP

MAX147EVC16-DIP

MAX147EVC32-DIP

TEMP. RANGE

0°C to +70°C

BOARD TYPE

Through-Hole

Component List

DESIGNATION QTY

C1, C7–C14

C2, C4, C6,

C15, C17–C20

C16

J18

JU1, JU2, JU5

R1–R8

R10–R13

R14

R15

R16

R17, R21

R18

None

DESCRIPTION

0.01µF ceramic capacitors

0.1µF ceramic capacitors

4.7µF tantalum capacitor

10µF tantalum capacitor

0.047µF ceramic capacitor

2x20 right-angle socket

10-pin header

2-pin jumpers

1kΩ, 5% resistors

10kΩ, 5%, 10-pin SIP resistor pack

Open

220kΩ, 5% resistor

180kΩ, 5% resistor

100kΩ trim pot

1MΩ, 5% resistors

100Ω, 5% resistor

Maxim MAX147BCPP

Maxim MAX872CPA

Maxim MAX393CPE

Maxim MAX666CPA

Maxim MAX495CPA

74HCT04

Maxim MAX494CPD

PC board

Software disk, MAX147 Evaluation Kit

QTY

MAX147EVC16

System Component List

DESCRIPTION

MAX147 Evaluation Kit (MAX147EVKIT-DIP)

68HC16 µC Module (68HC16MODULE-DIP)

MAX147EVC32

System Component List

QTY

DESCRIPTION

MAX147 Evaluation Kit (MAX147EVKIT-DIP)

80C32 µC Module (80C32MODULE-DIP)

MAX147 Stand-Alone EV Kit

The MAX147 EV kit provides a proven PC board layout

to facilitate evaluation of the MAX147. It must be

interfaced to appropriate timing signals for proper

operation. Refer to the MAX147 data sheet for timing

requirements.

The MAX147 EV kit operates with either a 3V supply or

a 5V supply. The EV kit’s own 3V regulator is powered

by a user-supplied 5V source. Trim pot R16 sets the

actual 3V voltage. R16 is adjustable from approximately

2.3V to 3.6V.

If a 3V power supply is already in use, disable the on-

board 3V regulator by unplugging the MAX666 from its

socket. Then connect the 3V supply to the VDD input

pad.

________________________________________________________________

Maxim Integrated Products

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.

For small orders, phone 408-737-7600 ext. 3468.

MAX147 Evaluation System/Evaluation Kit

Evaluates: MAX146/MAX147

3V-Only Systems

For 3V systems, unplug the MAX666 regulator and con-

nect your 3V power supply to the VDD input pad.

Connect the 3V and 5V input pads to each other to

power the MAX393. (The MAX393 can be powered with

3V or 5V. See

Detailed Description of Hardware

sec-

tion.) For development flexibility, the EV kit uses a

MAX393 to route the EXTCOM signal to COM or to the

CH0 input. Obtain the 3V DOUT and SSTRB signals

from the header J18, not from the 40-pin connector

(3V-only systems do not require the 74HCT04 level

translator).

Start the MAX147 software on the IBM PC by setting

the current directory to match the directory contain-

ing the Maxim programs, then type the program

name

MAX147.

Do not turn off or disconnect the µC

module while the program is running; if you do, you

will have to restart the program.

The program asks which µC module is in use and

to which port it is connected (the default µC is the

68HC16). For the 80C32 µC module, press µC to

select the 80C32. Press the space bar until the

correct PC serial port is highlighted, and press

ENTER. The MAX147 program is now in terminal-

emulation mode.

Turn on the µC module’s power. The module dis-

plays its log-on banner and tests its RAM.

Download and run the RAM resident program on

the µC module by pressing ALT+L (i.e., hold down

the ALT key as you strike the L key). The program

prompts you for the file name. Press the ENTER

key to download and run the file.

Systems Using 5V Logic

For 5V-logic systems, the 74HCT04 translates the

MAX147’s 3V outputs to 5V levels. The MAX147’s input

may be driven directly by 5V logic levels (obtain the 5V

DOUT and SSTRB signals from the 40-pin connector).

For 5V-only applications, refer to the MAX186/MAX188

analog-to-digital converters.

MAX147 EV System

The MAX147 EV system operates from a user-supplied

9V to 20V DC power supply, from which it generates a

5V supply for the µC board. A 3V regulator supplies

power to the MAX147. 3V to 5V level translators are

provided to interface the MAX147 with the µC board.

Quick Start

Copy the files from the distribution disk to your

hard disk or to blank floppy disks. Make sure that

the MAX147 EV kit software is in its own directory.

The necessary files are in the root directory of the

distribution disk, and the source code is in the

SOURCE subdirectory. The SOURCE subdirectory

is not required to operate the EV system.

Carefully connect the boards by aligning the

MAX147 EV kit’s 40-pin header with the µC mod-

ule’s 40-pin connector. Gently press them together,

so that they are flush against one another.

Connect a 9V to 15V DC power source to the µC

module at the terminal block. This is located next to

the on/off switch, in the upper-right corner of the µC

module. Observe the polarity marked on the board.

Connect a cable from the computer’s serial port to

the µC module. For 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 is selected.

Press ALT+C to switch to the control panel screen

after the RAM resident program is successfully

downloaded.

10) Apply input signals to the CH0–CH7 inputs at the

top edge of the MAX147 EV kit board. Observe

the readout on the screen. Table 3 lists the com-

mands available from the control panel screen.

11) Before turning off power to the MAX147 EV kit, exit

the program by pressing ALT+X.

Evaluating the MAX146

To evaluate the MAX146, turn off power to the EV kit,

remove the MAX147 IC, and replace it with a

MAX146BCPP. Disable the external reference by

removing jumpers JU2 and JU5. Type

MAX147 146

start the software.

Detailed Description

_________________________of Software

Shutdown Power Cycling (MAX147)

From the control panel, use the up/down arrow keys to

select the power cycling mode. Power cycling puts the

MAX147 in powerdown (FULLPD) mode between

readings. The MAX147 is always fully powered during

conversions.

Shutdown Power Cycling (MAX146)

From the control panel, use the up/down arrow keys to

select the power cycling mode. The MAX146 supports

FULLPD mode as well as FASTPD mode, where the

_______________________________________________________________________________________

MAX147 Evaluation System/Evaluation Kit

internal 1.2V bandgap reference remains active. The

MAX146 is always fully powered during conversions.

When used with the slower data-logging command,

specify the delay in seconds. The delay is between

enabled channels, and one line of data is logged after

all enabled channels have been polled.

Evaluates: MAX146/MAX147

Low-Speed Data Logging

The RS-232 serial link limits the data-logging sample

rate to no more than 10sps (samples per second). The

data-logging command is used to write data to a user-

specified file in plain comma-spaced-value text format.

From the control panel screen, press L. If a log file is

not already open, the software asks for a file name.

Only one log file is allowed per session. Once a log file

is open, press L to toggle data logging on or off.

With data logging enabled, “Logging” flashes on the

screen. One complete line of data is written after all

enabled channels are sampled.

The first line of the log file contains the column head-

ings. Each subsequent line of the log file contains all

eight channels, separated by commas. The values are

written as raw decimal output codes or as scaled volt-

ages, depending on which setting the control panel is

currently displaying. Use the C and V commands to

select the display format (Table 3). F3, the log data

marker command, can be used to sequentially tag dif-

ferent sections of the log file to indicate a change in

setup or input conditions. Pressing F3 writes an extra

entry at the end of the current line of the data log, to

indicate a change in setup or input conditions.

COM Voltage

COM is connected to ground (default) or to a user-

supplied analog common voltage applied to the

EXTCOM input pad. Press F6 to select the desired

COM connection.

The EV kit software can measure a user-applied COM

voltage. When F4 is pressed from the control panel

screen (Table 3), the software connects the EXTCOM

input pad to input channel 0. Next, the software con-

nects COM to ground. The channel 0 voltage is mea-

sured in single-ended unipolar mode. The measure-

ment is performed several times and averaged. After

measuring the external COM pad voltage, the switches

are restored to their previous configuration.

Operating with QSPI,

24 Bits per Transfer

The EV kit software program KIT147.S19 loaded into

the 68HC16 module uses a 24-bits-per-transfer mode,

which operates at 59ksps throughput. Refer to the tim-

ing diagrams in the

Clock Modes

section of the

MAX147 data sheet.

High-Speed Data Sampling

The S command samples rates over 10 samples per

second (sps). Data is collected from only one of the

eight channels at a rate from 100sps to 91ksps. First,

select the channel by pressing one of the number keys

0–7. Next, press F to specify the name of the file into

which the samples should be written. If the file already

exists, the screen displays “*** file already exists ***”.

To begin collecting data, press B. After the samples are

collected, the data is automatically uploaded to the

host and stored in the sample file.

Table 1. Recommended QSPI Setup

Parameters for 24 Bits per Transfer

(used in KIT147.S19)

PARAMETER

SPBR

CPOL

CPHA

BITS

DTL

TR0

TR1

CR0

CR1

RR1

5 (1.68MHz)

0 (clock is idle low)

0 (data is stable on clock rising edge)

16 (when enabled)

4 (7.6µs delay used in internal clock mode)

0000 0000 1xxx xxyy (configure and start

conversion)

0000 0000 0000 0000 (read data)

External clock: 1000 xxx0 (hold CS low).

Internal clock: 1010 xxx0 (hold CS low; DT

delay after transfer).

0100 xxx0 (16-bit enable)

Received data, left justified, with one lead-

ing zero bit

VALUE

Controlling the Sampling Rate

The rate for high-speed sampling, data logging, and

the oscilloscope demo mode (Table 3, key O) is con-

trolled by the D (delay between samples) command.

When used with the sample or oscilloscope demo com-

mands, specify the approximate delay in microseconds

or milliseconds by typing D, then the number, then “µsec”

or “msec”. Always verify timing by using an oscilloscope,

since this delay is not linear due to code overhead. The

fast sampling screen and oscilloscope demo mode use

delays from 100µs to 1000µs. The 68HC16 software sup-

ports delays between 68µs and 1000ms. The 80C32 soft-

ware supports delays between 450µs and 70ms.

_______________________________________________________________________________________

MAX147 Evaluation System/Evaluation Kit

Evaluates: MAX146/MAX147

Operating with QSPI,

16 Bits per Transfer

The program KIT14716.S19 demonstrates the 16-bits-

per-transfer interface scheme, which operates at 91ksps

throughput. In this demonstration,

is held low and

the QSPI operates continuously in the background.

Refer to the timing diagrams in the

Clock Modes

section

of the MAX147 data sheet. To use this program, follow

the instructions in

Quick Start,

but in step 8, download

KIT14716.S19 instead of KIT147.S19. After loading,

press ALT+C to switch to the control panel.

For lowest component count, enable the MAX146’s inter-

nal reference by removing the shunts from JU2 and

JU5. This enables the internal bandgap reference and

the reference buffer, driving VREF internally to 2.5V. A

0.01µF ceramic bypass capacitor near REFADJ (C1 on

the EV kit) provides noise filtering for the bandgap

reference.

Detailed Description

of Hardware

The MAX147 EV kit board includes a MAX666, config-

ured as a 3V regulator. Trim pot R16 adjusts the VDD

voltage between 2.3V and 3.6V.

The MAX872 is a micropower 2.5V reference.

The MAX494 and MAX495 are low-voltage, rail-to-rail op

amps with 500kHz gain-bandwidth product. The

MAX495 buffers the external COM input source. The

MAX494 can be used to buffer some of the input signals.

The MAX393 analog switch allows the EV kit software to

route the MAX147 COM pin to ground or to the external

COM input. In addition, the external COM input can be

routed to input channel 0. Typical systems connect

COM directly to analog ground or the analog common

voltage. The MAX393 can be powered by 3V, but if

driven by 5V logic (as is the case with the EV system), it

must be powered by 5V.

The 74HCT04 translates the DOUT and SSTRB signals

from 3V to 5V logic levels for interfacing to the µC mod-

ule. The MAX147’s logic inputs can be driven directly

from 5V logic levels.

Changing the Reference Voltage

The MAX147 EV kit software assumes a 2.5V reference

voltage, unless otherwise specified. When using a refer-

ence value other than 2.5V, specify the value when start-

ing the program. For example, if VREF is driven by a

2.048V reference, start the MAX147 software by typing:

MAX147 VREF 2.048

Or, on the MAX146, if REFADJ is driven by a 1.2V refer-

ence, start the MAX147 software by typing:

MAX147 146 REFADJ 1.2

The external reference’s temperature coefficient must

be 20ppm/°C or less to achieve accuracy to within four

LSBs over the 0°C to +70°C temperature range. For

12-bit accuracy over the 0°C to +70°C range, the refer-

ence’s temperature coefficient must be 4ppm/°C or less.

The MAX146 can use either its internal reference or an

external reference. On the EV kit, the internal reference

has been disabled by pulling REFADJ up to VDD (JU2)

and driving VREF with a MAX872 2.5V reference (JU5).

Input-Signal Buffering

The analog-to-digital converter (ADC) inputs require a

sufficiently low-impedance source for specified accura-

cy. An ADC can inject a small amount of charge at the

start of the acquisition time, and the source signal must

recover to within the desired accuracy before the

acquisition time ends. If the source by itself cannot do

this, use an op amp to buffer the input signal.

To buffer the CH4–CH7 input signals, unplug the 14-pin

header from U7, and install the supplied MAX494 quad

op amp in its place. Note the location of pin 1 toward

the upper right corner of the board.

When using an input buffer, the buffer output cannot

reach the power-supply rails.

If the MAX494 op-amp

buffer is installed and the input to the buffer is

grounded, the buffered output will not reach

ground.

The MAX494 allows its output signal to go to

within approximately 50mV of either supply.

Table 2. Recommended QSPI Setup

Parameters for 16 Bits per Transfer

(used in KIT14716.S19)

PARAMETER

SPBR

CPOL

CPHA

BITS

DTL

TR0

VALUE

5 (1.68MHz)

0 (clock is idle low)

0 (data is stable on clock rising edge)

4 (7.6µs delay used in internal clock mode)

0000 0001 xxxx xyy0 (configure and start

conversion)

External clock: 1100 xxx0 (16-bit transfer).

Internal clock: 1110 xxx0 (16-bit transfer

with DT delay).

Received data, left justified

CR0

RR0

_______________________________________________________________________________________

MAX147 Evaluation System/Evaluation Kit

Table 3. MAX147 EV Kit Command Reference

KEY

0, 1, 2, 3,

4, 5, 6, 7

FUNCTION

Enables or disables the corresponding input channel 0, 1, 2, 3, 4, 5, 6, or 7. The EV kit software scans all enabled

channels.

Displays the conversion results in decimal form.

Delay between samples. Delays longer than one second are handled by the IBM PC; otherwise, the µC module han-

dles the delay. Timing is approximate and should be verified with an oscilloscope.

Enables or disables data logging. If the -L command-line option was not specified, the L command prompts for a

log-file name.

Oscilloscope demo. Samples are collected and discarded as fast as possible. Observe waveforms and timing with

an oscilloscope.

Power-up delay. Timing is approximate and should be verified with an oscilloscope. When using an external refer-

ence, power-up delay is not necessary and should be set to zero. Power-up delay is used regardless of which

power-cycling mode is selected.

Samples one of the eight inputs at high speed. The sampling rate is controlled by the P and D delays. Due to pro-

gram overhead, the O and S commands operate at different rates. Timing should be verified with an oscilloscope.

Displays the conversion results in volts.

Chooses input scale (unipolar, bipolar, unipolar differential, bipolar differential) for all enabled channels. Disabled

channels are unaffected.

Writes a marker into the data-log file.

Measures the value of a user-applied COM voltage.

Changes the assumed value of VREF.

Changes the assumed voltage at COM. Selecting G connects the COM pin to ground; selecting E connects the

COM pin to the EXTCOM input pad.

Internal clock mode

External clock mode

Selects power-down mode.

Switches back to terminal mode.

Exits to DOS.

Evaluates: MAX146/MAX147

⇑

⇓

ALT+T

ALT+X

_______________________________________________________________________________________

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