graphed. Once displayed, the data can optionally be

saved 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 MAX1132

into the 68HC16. The sample rate is controlled by the

QSPI clock. To evaluate power-saving modes, these

automatic updates must be stopped. First, set the QSPI

clock control to STOP. This reconfigures the 68HC16’s

QSPI submodule to stop driving the serial clock. Second,

in the evaluation software’s main window, uncheck the

Read Every checkbox. Next, choose the desired software

power-down control word, and click the Read button to

send the new configuration to the MAX1132. If evaluating

the hardware shutdown, move JU2 to the 2-3 position.

Reference Voltage

The evaluation software assumes a +4.096V reference

voltage and a +12V full-scale voltage, unless otherwise

specified. Refer to the MAX1132 data sheet for more

information. To override these values, type the new val-

button.

Detailed Description

of Hardware

The MAX1132 (U1) is a high-speed, single-channel, 16-

bit data-acquisition system. There is no antialiasing filter

provided. The input signal may be applied directly to

JU2. High-impedance signal sources may require an

input buffer, which may be installed in the prototype

area. C4 bypasses the bandgap reference, and C3

bypasses the A/D converter‘s voltage reference. When

circuits are both powered by +5V. (Figure 1). Refer to the

MAX1132 data sheet.

Evaluating the MAX1133

To change the evaluation software's full-scale voltage

for use with the MAX1133, type 4.096 into the full-scale

Troubleshooting

Problem: No output measurement. System seems to

report zero voltage, or fails to make a measurement.

+4.096V reference voltage using a digital voltmeter.

MAX1132 Evaluation Kit/Evaluation System

4

_______________________________________________________________________________________