19-1688; Rev 0; 8/00
MAX1282 Evaluation System
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.
o
Proven PC Board Layout
o
Convenient On-Board Test Points
o
Data-Logging Software
o
Fully Assembled and Tested
Features
Evaluates: MAX1282
Ordering Information
PART
MAX1282EVKIT
MAX1282EVC16
TEMP. RANGE
0°C to +70°C
0°C to +70°C
INTERFACE
User supplied
Windows software
MAX1282EVC16 System
PART
MAX1282EVKIT
68HC16MODULE-DIP
QTY
1
1
DESCRIPTION
MAX1282 EV kit
68HC16
µC
module
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.
MAX1282EVKIT Files
FILE
DESCRIPTION
Installs the EV kit files on your computer
Application program
Software loaded into 68HC16
µC
INSTALL.EXE
MAX1282.EXE
KIT1282.C16
MAX1282EVKIT
Component List
DESIGNATION
C1−C4, C10
C9
C11, C13
C12, C14
J1
JU1
JU2
R1−R4
R9, R10
TP1
U1
None
None
None
None
QTY
5
1
2
2
1
1
1
4
2
1
1
1
1
1
1
DESCRIPTION
0.01µF ceramic capacitors
4.7µF tantalum capacitor
0.1µF ceramic capacitors
10µF, 10V tantalum capacitors
2x20 right-angle socket
2-pin header
3-pin header
300Ω
±5%
resistors
10Ω
±1%
resistors
8-pin header
Maxim MAX1282BCUE (16-pin
TSSOP)
PC board, MAX1282 EV kit
3-1/2in software disk, MAX1282
MAX1282 EV kit data sheet
MAX1282 data sheet
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.
Windows 95/98 is a registered trademark of Microsoft Corp.
________________________________________________________________
Maxim Integrated Products
1
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.
MAX1282 Evaluation System
Evaluates: MAX1282
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.
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.
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.
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.
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.
Table 1. Jumper Functions
JUMPER
JU1
POSITION
Closed*
Open
1-2*
2-3
FUNCTION
COM tied to GND
COM must be connected to
analog common
Operate
Shutdown
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-
JU2
*Default configuration
QSPI is a trademark of Motorola, Inc.
2
_______________________________________________________________________________________
MAX1282 Evaluation System
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.
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
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 V
REF
edit box
and press the Set V
REF
button. Note: This new V
REF
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.)
_______________________________________________________________________________________
3
Evaluates: MAX1282
MAX1282 Evaluation System
Figure 1. MAX1282 EV Kit Schematic
4
VDD1
1
V
DD1
C13
0.1µF
R10
10Ω
1%
TP1-7
J1-8
TP1-1
2
CH0
R1
300Ω
J1-37
3
CH1
R2
300Ω
C2
0.01µF
CH1
TP1-5
J1-31
J1-38
4
CH2
DIN
TP1-4
J1-36
13
R3
300Ω
5
CH3
SSTRB
12
R4
300Ω
6
COM
DOUT
11
1
J1-7
V
DD2
C14
10µF
10V
16
VDD2
C11
0.1µF
15
TP1-6
VDD1
CH0
SCLK
R9
10Ω
1%
C12
10µF
10V
C1
0.01µF
14
CS
GND
U1
MAX1282
J1-1
J1-2
J1-3
J1-4
CH2
C3
0.01µF
CH3
C4
0.01µF
TP1-3
J1-29
COM
JU1
2
TP1-2
J1-35
7
SHDN
1
SHDN
VDD1
REF
C9
4.7µF
10V
8
REF
GND
10
3 2
JU2
REFADJ
9
C10
0.01µF
REFADJ
_______________________________________________________________________________________
MAX1282 Evaluation System
Evaluates: MAX1282
Figure 3. MAX1282 EV Kit PC Board Layout—Component Side
Figure 2. MAX1282 EV Kit Component Placement Guide—
Component Side
Figure 4. MAX1282 EV Kit PC Board Layout—Solder Side
_______________________________________________________________________________________
5
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