TEMP DEMO WINDOW Click Temp Demo to access the Temperature Demo window (see Figure 6). The AD7793 evaluation board has a temperature demo included on the board. To operate the temperature demo, LK2 to LK6 should be inserted and LK1 removed. With these links in place, the excitation current of the AD7793 is connected to a 1 k thermistor that is connected across the AIN2(+)/AIN2(−) pins. In series with the thermistor is a 5 k precision resistor, which is used to generate the reference voltage so that a ratiometric configuration is used. The temperature demo software saves the values in the Mode Register, Configuration Register, and IO
Register. The software then configures the AD7793 to operate with a 210 µA excitation current; the AIN2(+)/AIN2(−) channel is selected as the analog input, the gain is set to 1, and the external reference REFIN(+)/REFIN(−) is selected. The software continuously reads the conversion from the AIN2(+)/AIN2(−) channel and converts the result to temperature using a look-up table.
To exit the Temperature Demo, click the BACK button. The software sets the Configuration Register, Mode Register, and I/O Register to their pretemperature demo values.
Figure 6. AD7793 Evaluation Software Temperature Demo Window
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