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TMS320F28377D: ADC-C and ADC-D in 16-bit Mode with -176Pin package.

GINILY
Intellectual 445 points
Part Number: TMS320F28377D


We have been using TMS320F28377DZWTT, with no problem setting ADCINC2 and ADCINC3 as the paired 16-bit Mode. We added a new design with TMS320F28377DPTPS recently, using the same ADCINC2 and ADCINC3. But the ADCRESULT0 always shows 0x0000. The ADCRESULT0 didn't show 0x0000 when switched to 12-bit mode.

Here is the 16-bit mode configuration:

    AdccRegs.ADCCTL2.bit.PRESCALE = 8; //set ADCCLK divider to /5, ADCCLK = 40MHz (Max is 50MHz)
    AdcSetMode(ADC_ADCC, ADC_RESOLUTION_16BIT, ADC_SIGNALMODE_DIFFERENTIAL); //Default use 16Bit, differential
    AdccRegs.ADCCTL1.bit.INTPULSEPOS = 1; //Set pulse positions to late
    //Configure Sine Feedback
    AdccRegs.ADCSOC0CTL.bit.CHSEL =2;
    AdccRegs.ADCSOC0CTL.bit.ACQPS = 119;
    AdccRegs.ADCSOC0CTL.bit.TRIGSEL = 17;
Please advise,
 
Best Regards,
Lily
  • 0
    TI__Guru 60865 points

    Hi Lily,

    The main things to check would be:

    • Configurations all got written and are as expected after your initialization code runs (using the expressions window)
    • ADC C2 channel is actually receiving triggers (I think you've proved this via switching the mode to 12-bit single-ended mode)
    • Also try C3 in 12-bit single-ended mode
    • Based on the single-ended conversion results of C2 and C3 (or by measuring or scoping the input pins directly), what is the input common mode?  Is it within 50mV of VREFHI/2?

    You may also want to check the basic system functionality as well:

    • VDDIO, VDDA, and VDD voltages are within normal operating range? 
      • Current consumption from these rails is within expectation? (or, as a crude check, the device is not getting hot?)
    • PLL settings are as expected and measuring XCLKOUT indicates that the device is actually running at 200MHz?
    • VREFH voltage is in the range of 2.5V to VDDA?
    • No analog input pins are experiencing an over-voltage or under-voltage condition? 

  • 0 in reply to Devin Cottier
    Intellectual 445 points

    Hi Devin,

    Thank you for your help! One of the analog input pins was too high!

    Best Regards,

    Lily