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CCS/TMS320F28027: About ADC Configuration

Madhuri Depuru
Intellectual 325 points
Part Number: TMS320F28027


Tool/software: Code Composer Studio

Hello ,

I am a newbie to microcontrollers. I started learning about ADC configuration from example "adc_soc". I didn't understand the following. please help

/ Wait for ADC interrupt
   for(;;)
   {
      LoopCount++;
   }
}

why LoopCount++ loop is required?

__interrupt void adc_isr(void)
{
  Voltage1[ConversionCount] = AdcResult.ADCRESULT1;  //discard ADCRESULT0 as part of the workaround to the 1st sample errata for rev0
  Voltage2[ConversionCount] = AdcResult.ADCRESULT2;

  // If 20 conversions have been logged, start over
  if(ConversionCount == 9)
  {
     ConversionCount = 0;
  }
  else
  {
      ConversionCount++;
  }

  AdcRegs.ADCINTFLGCLR.bit.ADCINT1 = 1;  //Clear ADCINT1 flag reinitialize for next SOC
  PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;   // Acknowledge interrupt to PIE

  return;
}

I have understood that adc_isr function is called in the " PieVectTable.ADCINT1 = &adc_isr;"

but what is the fuction of it and how come the loop is continuing?

  • 0
    Guru 192875 points

    Hi Madhuri,

    Madhuri Depuru said:
    why LoopCount++ loop is required?

    No specific reason but to simply count the total code cycle counts.

    Madhuri Depuru said:

    I have understood that adc_isr function is called in the " PieVectTable.ADCINT1 = &adc_isr;"

    but what is the fuction of it and how come the loop is continuing?

    The above is to map the ADC ISR to the ADC Interrupt in vector table.

    Let me know if you still have any doubts.

    Regards,

    Gautam

  • 0
    Genius 3050 points

    Hello, Madhuri.

    About your questions:

    Madhuri Depuru said:
    why LoopCount++ loop is required?

    "LoopCount++" is not really needed. It's just a counter, that you can check to insure, that your MCU is working fine. You can safely delete this line.

    Madhuri Depuru said:

    I have understood that adc_isr function is called in the " PieVectTable.ADCINT1 = &adc_isr;"

    but what is the fuction of it and how come the loop is continuing?

    It's not called in that line. This procedure is and ISR. That means, that this procedure will be called, when a particular INTERRUPT will be triggered. In your case this interrupt is "ADCINT1". The line " PieVectTable.ADCINT1 = &adc_isr;" means "when ADCINT1 interrupt will be triggered, call function with name "adc_isr"".

    So, your loop will be calculated, until the ADCINT1 interrupt occurs. Than your loop stops, "adc_isr" is calculated, and then you loop is continued.

    I strongly recommend you to spend time for examining some workshops, like this:

    Also you can check wiki - there are example projects and trainings:  

    I think these recources can help to cover lots of questions, that C2000 neophyte can have.

  • 0 in reply to Disona
    Intellectual 325 points

    Thank you Gautam & Disona

    your replies are really helpful

  • 0 in reply to Madhuri Depuru
    Guru 192875 points
    You're Welcome Madhuri!

    Goodluck & Regards,
    Gautam