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TMS320F280049: DAC and ADC

Tomotaroh Kohro
Mastermind 19805 points

Part Number: TMS320F280049

Hello Support team.

 

I am reading TRM of F28004x.

And I understood that input data of DAC is DACVALS.

 

I understood that input data of ADC-A can be DACA_OUT of DAC-A. (Figure 12.-1)

Also without any configuration, ADC-A can input from DACA_OUT same as A0/B15/C15 ball.

I think that these (A0/B15/C15 and DACA_OUT) signals do not need to be control as pin mux.

 

But A0/B15/C15 is connected with outside module. (DC/DC, ABC and so on).

Sometime customer wants to check DAC/ADC module as self-checking. In this case ADC-A needs to get some data from DACA_OUT of DAC-A. But if external module is running and it is connected with A0/B15/C15, it is difficult to do self-checking.

I would like to know if C2000 can control A0/B15/C15 stop to input data from external module such as disabling.

 

Best Regards

KORO

  • 0
    TI__Mastermind 28275 points
    Hi Koro,

    No, that is not possible. This is the way to think about it: A0/B15/C15 is a ADC pin.
    The ADC will sample whatever voltage is physically present on that pin whether this voltage comes internally from the device or externally.
    When DACA is enabled, there is an internal mux that connects DACOUTA to A0/B15/C15 and hence DACOUTA now drives A0/B15/C15. Due to this, after enabling DACA, you can't force an external voltage on A0/B15/C15 because you will have a contention of 2 voltages.

    Your options are to either move the signal on A0/B15/C15 to a different pin or use an external mux that decouples the signal from A0/B15/C15 every time you want to sample DACA.
  • 0 in reply to Frank Ankapong
    TI__Mastermind 19805 points
    Frank-san

    Thanks a lot.
    I understood but please allow me to confirm again as double-checking.

    > Your options are to either move the signal on A0/B15/C15 to a different pin

    Does this mean using another pin as HW because there is no PIN MUX function?

    Br
    KORO
  • 0 in reply to Tomotaroh Kohro
    TI__Mastermind 28275 points

    Koro,

    Yes it means using another pin.