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Original question:

TMS320F2800137: DAC

TMS320F2800157: ADC DAC Loopback Register vs Reading on the same ADC pin

Anurag
Prodigy 110 points

Part Number: TMS320F2800157
Other Parts Discussed in Thread: SYSCONFIG

The TRM describes the ADCDACLOOPBACK register which can be used to measure the DAC output on ADCA or ADCC. The TRM states that is using the DACL pin so does the pin for DACL need to be not driven by anything externally for the loopback to work properly?

Sysconfig complains if the CMPSS MUX Select pin isn't enabled in the Analog PinMux module. Is the input signal needed if we're only using the DACL output for loopback? If someone could point to me where the in block diagram this input is used, that would be appreciated.

Also, in this post https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1313196/tms320f2800137-dac

the loopback register isn't used at all. The ADC is just read as the DAC outputs since they are on the same pin. What's the difference between doing this vs the loopback register?

Thanks,

Anurag

  • 0
    TI__Genius 11081 points

    Hello Anurag,

    With the ADCDACLOOPBACK feature, there is no need to bring the DACL output onto a pin. The DAC output is sampled directly on an internal analog channel. There should be no need to configure the pinmux in this case.

    Best regards,
    Ibukun