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CCS/TMS320F28379D: Multiple ADC Software continuous execution (Results getting mixed up)

Hasan
Intellectual 405 points
Part Number: TMS320F28379D


Tool/software: Code Composer Studio

Hi,

I am using ADC Channel A0, A2 and A3 of TMS320F28379D synchronously. All the ADC's are software triggered. The result that i'm getting is all mixed up. When i change the analog value on ADC0, it gives the ADC result on ADCRESULT0 but at the same time changing the values on ADCRESULT2 AND ADCRESULT3. The same happens when i update the analog value on ADC Channel A2 and A3. I have added the screenshots of my code. Please check what i'm missing.

  • 0
    TI__Genius 10845 points
    Hi Hasan,

    The above configuration looks correct only. How much change in result are you observing on other channels?

    Thanks
    Vasudha
  • 0 in reply to Vasudha Bhadoria
    Intellectual 405 points
    Sorry, i by mistake clicked this resolved my issue. How do i undo it?

    Currently, i am using 2 variable resistors on both ADC Channel A0 and A3. Both varying the voltage from 0 to 3.3 Volt. But what happen in Debug window, even though nothing is connected at channel A2. When the voltage at channel a0 is 1v, the voltage at channel a2 shows 0.5v and as i increase the voltage at channel A0, the voltage at channel a2 also increases. The change in channel a0 voltage also effects the channel a3 and vice versa
  • 0 in reply to Hasan
    Intellectual 405 points

    I also tried to run the example "adc_soc_software_cpu01.c" but got same results. The results i am getting in the ADC Result Regs (A2,A3,B2,B3). The issue is whenever i change the analog value on ADC Channel A2, it gives ADC Result A2 Value accordingly but at the same time changing the ADC Result A3 Value at some extent. The same thing happens vice versa and when i am using ADC B Channels. I have added some screen shots that may help you. In some cases, when ADC Channel A2 is disconnected and A3 is connected, there will still be some value at A2 which varies when i change the analog value at channel A3. 

    In this screen shot, there is nothing connected at AdcaResult0 and AdcbResult1, but still there are some values which changes as i vary AdcaResult1 AdcbResult0.

  • 0 in reply to Vasudha Bhadoria
    Intellectual 405 points
    Hi Vasudha, Still waiting for your suggestion.
  • 0 in reply to Hasan
    TI__Genius 10845 points
    Hi,

    This is not expected. Can you check if inputs are being provided as expected?
    Also, can you confirm the same issue in code as well. Since the debug window refreshes are slow and if inputs are changed frequently, you might not be seeing the corresponding values.

    Thanks
    Vasudha