MAX116EVB16 [MAXIM]

Complete Evaluation System Samples to 40ksps;


型号：	MAX116EVB16
厂家：	MAXIM INTEGRATED PRODUCTS
描述：	Complete Evaluation System Samples to 40ksps
文件：	总7页 (文件大小：223K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

19-2404; Rev 0; 6/01

MAX115 Evaluation Kit

General Description

Features

ꢀ Proven PC Board Layout

The MAX115 evaluation system (EV system) is a com-

plete, eight channel data-acquisition system consisting

of a MAX115 evaluation kit (EV kit) and a Maxim

68HC16MOD-16WIDE microcontroller (µC) module. The

MAX115 is a high speed, multichannel, 12-bit data

acquisition system with simultaneous track/holds.

Windows 3.1/Windows 95 software provides a handy

user interface to exercise the MAX115’s features.

ꢀ Complete Evaluation System Samples to 40ksps

ꢀ Convenient Test Points Provided On-Board

ꢀ Data-Logging Software with FFT Capability

ꢀ Fully Assembled and Tested

Order the complete EV System (MAX115EVB16) for

comprehensive evaluation of the MAX115 using a per-

sonal computer. Order the EV kit (MAX115EVKIT) if the

68HC16MOD-16WIDE Module has already been pur-

chased with a previous Maxim EV system or for custom

use in other µC-based systems.

Ordering Information

MAX115EVKIT/MAX116EVKIT Parts List

PART

TEMP. RANGE

0 C to +70 C

INTERFACE TYPE

User-Supplied

DESIGNATION QTY

DESCRIPTION

MAX115EVKIT

MAX115EVB16

MAX116EVKIT

MAX116EVB16

C1, C2, C4, C5,

0.1µF ceramic 1206 chip

capacitors

Windows Software

User-Supplied

C6, C9, C10

C3, C8

10µF, 25V tantalum capacitors

4.7µF, 6.3V tantalum capacitor

100pF ceramic 1206 chip

Windows Software

C11

P1, P2

2 x 20 right angle sockets

R1, R6

100

10k

1ꢀ 1206 chip resistors

5ꢀ 1206 chip resistors

MAX115EVB16 System Component List

R2, R3, R4, R5

R7, R8

PART

QTY

DESCRIPTION

MAX115EVKIT

MAX115 Evaluation Kit

Maxim MAX115CAX or

MAX116CAX

68HC16 MOD-

16WIDE

68HC16 µC Module with 16-bit

parallel interface

78L05 voltage regulator

74HCT244

79L05 negative voltage regulator

16MHz clock oscillator module

PC board

MAX116EVB16 System Component List

NONE

PART

QTY

DESCRIPTION

Software disk, “MAX115

Evaluation Kit”

NONE

MAX116EVKIT

MAX116 Evaluation Kit

68HC16 MOD-

16WIDE

68HC16 µC Module with 16-bit

parallel interface

MAX115 EV Kit File List

INSTALL.EXE

MAX115.EXE

MAX115.HLP

KIT125.B16

MAX115.INI

UNINST.EXE

Installs the EV kit files on your computer

Application program

Help file

Software loaded into 68HC16

Program settings

Removes the EV kit files from your computer

________________________________________________________________ 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.

MAX115 Evaluation Kit

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

Observe the polarity marked on the board.

MAX115 Stand-Alone EV Kit

The MAX115 EV kit provides a proven PC board layout

to facilitate evaluation of the MAX115. It must be inter-

faced to appropriate timing signals for proper opera-

tion. Dual power supplies ( 8VDC min, 20VDC maxꢁ

should be applied to P1-5, P1-9, with ground at P1-1.

Connect active-low read strobe to P1-38, connect write

strobe to P1-37, and connect memory mapped chip

selects to P1-35 and P1-36. Refer to Figure 1, MAX115

EV Kit Schematic for board schematic. Refer to the

MAX115 data sheet for timing requirements.

3ꢁ 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, DCDꢁ to confirm that the correct port

has been selected.

4ꢁ Install the MAX115 EV kit software on your comput-

er by running the INSTALL.EXE program on the

floppy disk. The program files are copied and icons

are created for them in the Windows 3.1 Program

Manager (or the Windows 95 Start Menuꢁ.

MAX115 EV System

The MAX115/MAX116 EV systems operate from a user-

supplied +13V to +20V DC power supply. Windows

3.1/95 software running on an IBM PC interfaces to the

EV system board through the computer’s serial commu-

nications port. The software can be operated with or

without a mouse. Refer to Quick Start section for setup

and operating instructions.

5ꢁ Start the MAX115 program by opening its icon in

the Program Manager (or Start Menuꢁ.

6ꢁ 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

KIT125.B16 to the module.

The MAX115 software is designed for use with the

complete evaluation system MAX115EVB16 or

MAX116EVB16 (includes 68HC16MOD-16WIDE mod-

ule together with MAX115EVKIT or MAX116EVKITꢁ. If

the MAX115 evaluation software will not be used, the

MAX115EVKIT board can be purchased by itself with-

out the microcontroller.

7ꢁ Apply input signals to the inputs labeled CH1A-

CH4A at the bottom edge of the MAX115 EV kit

board. Observe the readout on the screen.

Detailed Description

of Software

The MAX115 digitizes up to four inputs from either the A

or B input bank. Conversion time is determined by the

number of enabled inputs. The software collects sam-

ples at a maximum throughput of 40ksps (one channelꢁ

to 26ksps (four channelsꢁ. The various program func-

tions are grouped into dialog boxes, which are accessi-

ble from the Window menu on the main menu bar.

To evaluate the MAX116, order the complete evaluation

system MAX116EVB16 or just the interface board

MAX116EVKIT.

Quick Start

Before you begin, you will need:

•

Maxim’s MAX115EVB16 (contains MAX115EVKIT

board and 68HC16MOD-16WIDEꢁ

A small DC power supply (+13V to +20V DC at

250mAꢁ

Keyboard Navigation

If a mouse or other pointing device is not available,

operate the program using the following keyboard

shortcuts. Press ALT+W to bring up the Window menu

and then select a tool window. Press the TAB key to

select controls within the selected tool window. Buttons

are activated by pressing the space bar. Check boxes,

radio buttons, and combo boxes respond to the

up/down arrow keys. Refer to Table 1, Keyboard

Navigation Shortcuts.

An IBM PC-compatible computer running Windows

3.1 or Windows 95

•

A spare serial communications port (9-pin plugꢁ

A serial cable to connect the computer’s serial port

to the Maxim 68HC16MOD-16WIDE module

1ꢁ Carefully connect the boards by aligning the two

40-pin headers of the MAX115 EV kit with the two

40-pin connectors of the 68HC16MOD-16WIDE

module. Gently press them together. The two

boards should be flush against one another.

2ꢁ Connect a +13V to +20V DC power source to the

µC module at the terminal block located next to the

_______________________________________________________________________________________

MAX115 Evaluation Kit

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.

Table 1. Keyboard Navigation Shortcuts

KEY

FUNCTION

Select next control

TAB

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

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.

ALT + Print

Screen

Copy the image of main window onto the

clipboard

Low-Speed Data Logging

Readings can be taken automatically from user-selected

channels at regular intervals up to ten samples per sec-

ond by selecting “Scan Tool” from the “Window”menu.

The Channel Selection and Configuration group con-

trols which channels shall be scanned, and (where

applicableꢁ configures each channel for bipolar and/or

differential input. The Bipolar and Differential controls

are disabled because the MAX115 inputs are always

bipolar and never differential. The scan rate combo box

controls the rate at which measurements are made.

Readings are displayed in the Recent Values text

area. Readings may optionally be recorded into a data

log file. Click on the “New Log” button to begin or end

data logging. This brings up the "Log File Format" dia-

log box. One complete line of data is written after all

enabled channels have been sampled. The first line of

the log file contains the column headings. Each subse-

quent line of the log file contains all enabled channels,

separated by commas, tabs, or spaces (previously

selected in the Log File Format dialog boxꢁ. Once a log

file has been opened, it can be paused or resumed

with the corresponding Log menu commands. The pro-

gram continues to write data to the log file until the

Stop Log button is clicked.

The MAX115 EV kit software performs power-up by

writing a configuration word with the shutdown bit set.

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

allow time for the reference voltage to stabilize so that

an accurate measurement may be performed.

Sampling Tool

To sample data at rates up to 40ksps (samples per

secondꢁ, select “Sampling Tool” from the “Window”

menu, make your selections, and click on the Start but-

ton. The timing delays may be adjusted as appropriate

to control the sample rate. The effective sample rate

can be estimated by taking the reciprocal of the sum of

the delay between samples, the power-up delay and

the conversion time. Sample size is restricted to a

power of two, so that the data can be processed by the

FFT tool. The sample size control controls the number

of samples collected on each selected channel. After

the samples have been collected, the data is automati-

cally uploaded to the host and is graphed. Once dis-

played, the data can optionally be saved to a file.

FFT Tool

The MAX115 evaluation software includes an FFT (Fast

Fourier Transformꢁ tool that can display the spectral

content of data collected with the high-speed sampling

tool. To view the spectral content of a waveform, first

select a data sample that was previously collected with

the high-speed sampling tool. Then, select “FFT Tool”

from the “Window” menu. Check the output plots

desired, and click on the Start button. A data window-

ing function preprocesses a data sample before per-

forming the FFT. When the input signal is not synchro-

nized to the sampling clock, spectral energy appears

to leak into nearby frequency buckets. A suitable data

One-Shot Read Tool

The One-Shot Read Tool allows direct control of the

A/D configuration. Select the channel and mode of

operation to update the Control Byte display, or

change the Control Byte bits 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.

Power Cycling Tool

To reduce average supply current demand, the

MAX115 can be shut down between conversions. From

_______________________________________________________________________________________

MAX115 Evaluation Kit

window tapers the raw data to zero amplitude at the

beginning and end, reducing this spectral leakage. 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.

MAX115. CS8 is the chip-select output for the 7E800

memory-mapped I/O area, which the EV system uses to

generate the conversion start strobe that signals the

MAX115 to sample its inputs.

Measuring Supply Current

EV kit supply current can be monitored by measuring the

voltage across resistor R1 (for the +5V supplyꢁ or R6 (for

Device Characteristics

The device characteristics dialog box contains parame-

ters that are not expected to change often. The device

selection is used to evaluate devices similar to the main

device type.

the -5V supplyꢁ. These resistors are 100

1ꢀ, thus

0.001V across R1 represents 10µA of supply current.

Troubleshooting

Problem: No output measurement. System seems to

report zero voltage, or fails to make a measurement.

Evaluating the MAX116

The MAX115 software can evaluate the MAX116 directly.

From the “Window” menu, pick “Device Characteristics”.

Next, change the device type from MAX115 to MAX116.

This tells the program that the input voltage span is

Check +5V and -5V supply voltages. Check the 2.5V

REFOUT reference voltage using a digital voltmeter.

Use an oscilloscope to verify that the 16MHz clock is

running and that the conversion-start signal is being

strobed.

instead of 2V

REF

Problem: Measurements are erratic, unstable; poor

accuracy.

Changing the Reference Voltage

The MAX115 EV kit software assumes a +2.5V refer-

ence voltage, unless otherwise specified. Apply an

external +2.5V reference to the REFIN pad to overdrive

the internal reference. See the MAX115 data sheet for

more information. From the “Window” menu, select

“Device Characteristics”. Type the new reference volt-

age into the reference voltage edit box.

Check the reference voltage using a digital voltmeter.

Use an oscilloscope to check for noise. When probing

for noise, keep the oscilloscope ground return lead as

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

Problem: Inputs appear on wrong channels.

Check the MAX115 clock pin with an oscilloscope. A

crystal oscillator module with fast rise/fall times can

overshoot or undershoot the power supply rails, violat-

ing device operation limits. Use a lowpass filter (such

as R7 and C11 on the MAX115 EV kitꢁ to eliminate

clock overshoot.

Detailed Description

of Hardware

The MAX115 (U1ꢁ is a high-speed, multichannel, 12-bit

data-acquisition system with simultaneous track/holds.

Linear regulators (U2 and U4ꢁ make clean analog 5V

power supplies for the MAX115. R8 and C1 filter digital

noise out of the analog power supply. U3 isolates the

CS, RD, WR, and CONVST signals from the main sys-

tem bus to further prevent digital noise from entering

the MAX115. Refer to Figure 1, MAX115 EV Kit

Schematic and the MAX115 data sheet.

CS7 is the chip-select output for the 7E000 memory-

mapped I/O area, which the EV system uses to write

the configuration byte to, and read data from the

_______________________________________________________________________________________

MAX115 Evaluation Kit

MAX16

U3B

Figure 1. MAX115/MAX116 EV Kit Schematic

_______________________________________________________________________________________

MAX115 Evaluation Kit

1.0"

Figure 2. MAX115/MAX116 EV Kit Component Placement

Guide

Figure 3. MAX115/MAX116 EV Kit PC Board Layout —

Component Side

_______________________________________________________________________________________

MAX115 Evaluation Kit

1.0"

Figure 4. MAX115/MAX116 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.

MAX116EVB16 [MAXIM]

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