Evaluates: MAX1284
MAX1284 Evaluation System
2_______________________________________________________________________________________
Quick Start
1) Carefully connect the boards by aligning the 40-pin
header of the MAX1284 EV kit with the 40-pin con-
nector of the 68HC16MODULE-DIP module, both
boards component-side up. Gently press them
together. The two boards should be flush against
one another.
2) Ensure that JU1 is open and JU2 is in the 1-2 posi-
tion.
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 MAX1284 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 MAX1284 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
KIT1284.C16 to the module.
8) Apply an input signal between AIN and GND.
Observe the readout on the screen.
Detailed Description
MAX1284 Stand-Alone EV Kit
The MAX1284EVKIT provides a proven PC board layout
to evaluate the MAX1284. It must be interfaced to
appropriate timing signals for proper operation.
Connect +5V to VDD, and connect the ground return to
GND (Figure 1). Refer to the MAX1284 data sheet for
timing requirements.
MAX1284 EV System
The MAX1284EVC16 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 setup
and operating instructions.
Software Description
The evaluation software’s main window controls the
serial-clock speed and sample rate. It displays the volt-
age and output code as well as some statistics of the
input signal. A separate graph window shows the data
changing in real time. The update rate is limited to
about 10 samples per second, due to COM port band-
width limitations.
Statistics
The Minimum and Maximum fields show the highest
and lowest readings acquired. The Average field
shows a running mean based on the equation
ai= (k)(xi) + (1 - k)(ai - 1). 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),
sampling size (Sample! menu item), and press Begin
Sampling! (in Sample! pop-up window). Sample size is
restricted to a power of 2 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 graphed. Once displayed, the data can
be saved optionally 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.
Evaluating Shutdown
The evaluation software configures the 68HC16’s QSPI
submodule to continuously read data from the
MAX1284 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” checkbox. 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 MAX1284
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.
QSPI is a trademark of Motorola, Inc.