Part Number: TMS320F28035
Hi,
I have read Silicon Errata of TMS320F28035, in the follow picture, it says, need to discard the first ADC conversion. But in function AdcOffsetSelfCal() , Fist ADC result is used, why,Is there a mistake in my understanding？
many thanks.
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Uint16 AdcConversion(void)
{
Uint16 index, SampleSize, Mean, ACQPS_Value;
Uint32 Sum;
index = 0; //initialize index to 0
SampleSize = 256; //set sample size to 256 (**NOTE: Sample size must be multiples of 2^x where is an integer >= 4)
Sum = 0; //set sum to 0
Mean = 999; //initialize mean to known value
//Set the ADC sample window to the desired value (Sample window = ACQPS + 1)
ACQPS_Value = 8;
AdcRegs.ADCSOC0CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC1CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC2CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC3CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC4CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC5CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC6CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC7CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC8CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC9CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC10CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC11CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC12CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC13CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC14CTL.bit.ACQPS = ACQPS_Value;
AdcRegs.ADCSOC15CTL.bit.ACQPS = ACQPS_Value;
//Enable ping-pong sampling
// Enabled ADCINT1 and ADCINT2
AdcRegs.INTSEL1N2.bit.INT1E = 1;
AdcRegs.INTSEL1N2.bit.INT2E = 1;
// Disable continuous sampling for ADCINT1 and ADCINT2
AdcRegs.INTSEL1N2.bit.INT1CONT = 0;
AdcRegs.INTSEL1N2.bit.INT2CONT = 0;
AdcRegs.ADCCTL1.bit.INTPULSEPOS = 1; //ADCINTs trigger at end of conversion
// Setup ADCINT1 and ADCINT2 trigger source
AdcRegs.INTSEL1N2.bit.INT1SEL = 6; //EOC6 triggers ADCINT1
AdcRegs.INTSEL1N2.bit.INT2SEL = 14; //EOC14 triggers ADCINT2
// Setup each SOC's ADCINT trigger source
AdcRegs.ADCINTSOCSEL1.bit.SOC0 = 2; //ADCINT2 starts SOC0-7
AdcRegs.ADCINTSOCSEL1.bit.SOC1 = 2;
AdcRegs.ADCINTSOCSEL1.bit.SOC2 = 2;
AdcRegs.ADCINTSOCSEL1.bit.SOC3 = 2;
AdcRegs.ADCINTSOCSEL1.bit.SOC4 = 2;
AdcRegs.ADCINTSOCSEL1.bit.SOC5 = 2;
AdcRegs.ADCINTSOCSEL1.bit.SOC6 = 2;
AdcRegs.ADCINTSOCSEL1.bit.SOC7 = 2;
AdcRegs.ADCINTSOCSEL2.bit.SOC8 = 1; //ADCINT1 starts SOC8-15
AdcRegs.ADCINTSOCSEL2.bit.SOC9 = 1;
AdcRegs.ADCINTSOCSEL2.bit.SOC10 = 1;
AdcRegs.ADCINTSOCSEL2.bit.SOC11 = 1;
AdcRegs.ADCINTSOCSEL2.bit.SOC12 = 1;
AdcRegs.ADCINTSOCSEL2.bit.SOC13 = 1;
AdcRegs.ADCINTSOCSEL2.bit.SOC14 = 1;
AdcRegs.ADCINTSOCSEL2.bit.SOC15 = 1;
DELAY_US(ADC_usDELAY); // Delay before converting ADC channels
//ADC Conversion
AdcRegs.ADCSOCFRC1.all = 0x00FF; // Force Start SOC0-7 to begin ping-pong sampling
while( index < SampleSize ){
//Wait for ADCINT1 to trigger, then add ADCRESULT0-7 registers to sum
while (AdcRegs.ADCINTFLG.bit.ADCINT1 == 0){}
AdcRegs.ADCINTFLGCLR.bit.ADCINT1 = 1; //Must clear ADCINT1 flag since INT1CONT = 0
Sum += AdcResult.ADCRESULT0;
Sum += AdcResult.ADCRESULT1;
Sum += AdcResult.ADCRESULT2;
Sum += AdcResult.ADCRESULT3;
Sum += AdcResult.ADCRESULT4;
Sum += AdcResult.ADCRESULT5;
Sum += AdcResult.ADCRESULT6;
// Wait for SOC9 conversion to start, which gives time for SOC7 conversion result
while( AdcRegs.ADCSOCFLG1.bit.SOC9 == 1 ){}
Sum += AdcResult.ADCRESULT7;
//Wait for ADCINT2 to trigger, then add ADCRESULT8-15 registers to sum
while (AdcRegs.ADCINTFLG.bit.ADCINT2 == 0){}
AdcRegs.ADCINTFLGCLR.bit.ADCINT2 = 1; //Must clear ADCINT2 flag since INT2CONT = 0
Sum += AdcResult.ADCRESULT8;
Sum += AdcResult.ADCRESULT9;
Sum += AdcResult.ADCRESULT10;
Sum += AdcResult.ADCRESULT11;
Sum += AdcResult.ADCRESULT12;
Sum += AdcResult.ADCRESULT13;
Sum += AdcResult.ADCRESULT14;
// Wait for SOC1 conversion to start, which gives time for SOC15 conversion result
while( AdcRegs.ADCSOCFLG1.bit.SOC1 == 1 ){}
Sum += AdcResult.ADCRESULT15;
index+=16;
} // end data collection
//Disable ADCINT1 and ADCINT2 to STOP the ping-pong sampling
AdcRegs.INTSEL1N2.bit.INT1E = 0;
AdcRegs.INTSEL1N2.bit.INT2E = 0;
while(AdcRegs.ADCSOCFLG1.all != 0){} // Wait for any pending SOCs to complete
// Clear any pending interrupts
AdcRegs.ADCINTFLGCLR.bit.ADCINT1 = 1;
AdcRegs.ADCINTFLGCLR.bit.ADCINT2 = 1;
AdcRegs.ADCINTOVFCLR.bit.ADCINT1 = 1;
AdcRegs.ADCINTOVFCLR.bit.ADCINT2 = 1;
//reset RR pointer to 32, so that next SOC is SOC0
AdcRegs.SOCPRICTL.bit.SOCPRIORITY = 1;
while( AdcRegs.SOCPRICTL.bit.SOCPRIORITY != 1 );
AdcRegs.SOCPRICTL.bit.SOCPRIORITY = 0;
while( AdcRegs.SOCPRICTL.bit.SOCPRIORITY != 0 );
Mean = Sum / SampleSize; //Calculate average ADC sample value
return Mean; //return the average
}//end AdcConversion
