Digital-to-Analog Converter Window

The MAX1234: Digital to Analog Converter window con-

trols the voltage at the DACOUT pin. Enter the DAC

code value between 0 and 255, and click Write DAC.

The DAC can be powered off by clicking DAC Off (see

Figure 4).

For improved accuracy, set the DAC output code to

255 and measure the actual DACOUT voltage. Enter

the full-scale voltage into DAC Full-Scale Voltage to

adjust the reported ideal DAC output voltage.

Keypad Window

Use the drop-down combo boxes to set up the keypad

control register, then click Write KEY Control. Refer to

the MAX1234 data sheet for suggested usage details

(see Figure 5).

Click Read KPDATA1 to read data masked by the col-

umn mask. Click Read KPDATA2 to read keypad data

masked by the key mask and column mask. Active key

presses are highlighted on the keypad display.

Mask individual keys using the appropriate

R1C1...R4C4 checkboxes and clicking Write key

mask. Or mask an entire column using the C1–C4

checkboxes and clicking Write column mask. Masked

keys are grayed on the keypad display.

GPIO Window

The GPIO screen reassigns the keypad pins to general-

purpose input and output. Keypad pins R1–R4 and

C1–C4 can be individually assigned to GPIO. The

Write GPIO button writes all of the GPIO registers from

the checkboxes. Each GPIO pin can be configured as

an input, a totem-pole output, or an open-collector out-

put (see Figure 6).

MAX1234 Evaluation System/Evaluation Kit

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Figure 1. EV Software’s Main Window

Note: The evaluation software’s main window provides direct access to all registers, and controls the interrupt response.