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ADC self calibration AdcOffsetSelfCal()

Stefan Fischer
Intellectual 680 points

Other Parts Discussed in Thread: TMS320F28032

Hi

 i have a question about AdcOffsetSelfCal() if i use external reference do i have to set  

AdcRegs.ADCCTL1.bit.ADCREFSEL = 1;

Or is the selfcalibration always done with the internal BG ?

thx

S.Fischer

  • 0
    Guru 192875 points

    Hi Stefan,

    For external reference you've to use 

    01 - External reference, 2.048 V on ADCREFIN
    10 - External reference, 1.500 V on ADCREFIN
    11 - External reference, 1.024 V on ADCREFIN

    if you don't mention ADCREFIN value, by default 00 - Internal reference (default) is selected.

    Do refer: SPRU716D for more info.

    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    Intellectual 680 points

    I should have mentioned that i use the TMS320F28032 which has only a 3.3V external Reference. 

    so which should i use in the calibration Routine Internal or external Reference? 

     

  • 0 in reply to Stefan Fischer
    TI__Guru 60865 points

    Hi Stefan,

    Internal/external reference shouldn't make very much if any difference for offset, but I would nevertheless recommend that you setup your ADC as you intend to use it before using self-calibration as a best-practice. You should therefore setup the ADC in external reference mode and also set the clock as you intend to use it, set overlap mode as you plan to use it, and any other configurations as you intend to use them.