SFFS779 December 2024 TMS320F28P550SJ
Integrity of DAC and ADC can be checked by monitoring the DAC output using ADC. DAC can be configured using software to provide a set of predetermined voltage levels. These voltage levels can be measured by the ADC and results thus obtained can be cross checked against the expected value to verify the DAC and ADC are functioning properly. This technique can be applied during run time to verify that proper voltage levels are being driven from DAC.
For more information on the DAC channels that can be sampled by ADC without external board level connections, refer to the device-specific data sheet or technical reference manual. While performing the loopback checks for 16-bit differential input mode, two DACs must be used to provide input to the ADC. To avoid common cause failures, TI recommends keeping the reference voltages of the ADC and DAC different while performing the test. In addition, the input signal to ADC must not be driven by any other sources while the test is being performed.