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Evaluate: MAX1400/MAX1402
10) Apply input signals to the inputs labeled
AIN1–AIN5, at the bottom-edge of the MAX1402 EV
kit board. AIN6 is analog common. Observe the
readout on the screen.
Upgrading the 68HC16 Module
The MAX1402 EV kit requires Rev. 2.0 of the Maxim
68HC16 Module ROM. Check the label on device U3
on the module; if its label says Rev. 1.0, contact the
factory for a replacement.
To install the new ROM, use the following procedure.
Use antistatic handling precautions. To reduce the risk
of ESD damage, gather all required materials and per-
form the installation at one sitting:
1) Slide the ON/OFF switch to the OFF position.
2) Using a flat-blade screwdriver, gently pry U3, the
REV 1.0 ROM, out of its socket.
3) Remove the REV 2.0 ROM from its antistatic pack-
aging.
4) Align the REV 2.0 ROM in the U3 socket pins.
Observe correct polarity (the notch at the top of the
ROM). Verify that the pins are lined up with the
socket, and gently press the ROM into place.
Proceed to the regular Quick Start instructions.
Detailed Description
_________________________of Software
The MAX1402 digitizes up to seven inputs. The various
program functions are grouped into windows, which are
accessible from the Show menu on the main menu bar.
Main Display
The main display shows the calculated input voltage
and raw A/D output code for each active channel.
Although there are nine input channels, only certain
configurations are allowed.
Select any single channel or one of the scanning
sequences from the Inputs menu. AIN 1-6 designates
an analog input between the AIN1 pin and the AIN6 pin.
CALOFF designates the signal between the CALOFF+
and CALOFF- pins. CALGAIN designates the signal
between the CALGAIN+ and CALGAIN- pins.
The EV kit software assumes that CALOFF+ and
CALOFF- are grounded so that CALOFF measures zero
volts. Similarly, the software assumes that CALGAIN+ is
connected to REFIN+ and CALGAIN- is connected to
REFIN- so that CALGAIN measures the reference volt-
age. These two points calibrate the code-to-voltage
translation function performed in the software.
The MAX1400/MAX1402 automatically triggers its mea-
surements, unless the FSYNC control bit is set. The
evaluation kit software communicates with the
MAX1400/MAX1402 at intervals determined by the
Update Every combo box. To halt this automatic update,
uncheck the Update Every checkbox or change the
Update Every to a value between 100ms and 60000ms.
Normally, the microcontroller collects new data as soon
as it becomes available, by using the INT pin to trigger
an interrupt service routine. If the INT pin is not used as
an interrupt, then the MAX1400 must not be operated in
free-running mode. Check or uncheck the Use INT
Interrupt checkbox to configure the evaluation kit soft-
ware.
Configuration Tool
The Configuration Tool controls parameters that apply
to the entire EV kit. Like the other windows, the
Configuration Tool can be activated from the Show
menu of the main menu bar. The CLK control should
match the external ceramic resonator or crystal that
sets the master clock frequency. The VREF Reference
Voltage control tells the software what the reference
voltage is. This is used to convert the raw A/D output
codes into the corresponding input voltage to speed
user evaluation. The Data Rate control determines how
often the MAX1402 performs a measurement. Some
data rates provide 16-bit, noise-free resolution when
used with the SINC3 filter (discussed below). The Filter
Sync control can be used to inhibit the MAX1402 from
performing its self-timed measurements. The Buffer
Inputs checkbox enables the internal input buffers. The
Burnout Test Currents checkbox enables two small
(0.1µA) current sources to provide an input stimulus.
When used with a transducer, these current sources
can be used to verify that the transducer has not failed
open or short circuit.
At the bottom of the window, there are input voltage
range selection buttons. These buttons configure all
input channels for the same input voltage range.
Although the MAX1400/MAX1402 can be operated with
three different input ranges at the same time, the evalu-
ation kit software only supports a single range for all
channels.
The digital filter on the MAX1402 can be configured for
SINC
3
or SINC
1
operation, which affects the filter cutoff
frequency. (SINC' means SIN(X) ÷ X, and SINC
3
means
(SIN(X) ÷ X)
3
.) The SINC
3
filter is required for 16-bit accu-
racy. The SINC
1
filter provides faster settling time with less
accuracy. Alternatively, the raw modulator output can be
driven out the DOUT pin; however, the EV kit software
cannot read data from the MAX1402 in this mode.
MAX1402 Evaluation Kit/Evaluation System
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