CCS/PGA900EVM: pga900EVM

chennangan

Part Number: PGA900EVM

Tool/software: Code Composer Studio

/* ========================================================================== */
interrupt void PADC_Handler(void)
{
#if (ADC_24_BIT_TESTING == 1)
signed long xx,yy;
xx = (PADC_DATA_24BIT & 0x00FFFFFF);/* Mask the upper 8 bits */
if(xx & 0x00800000) /* If sign bit is set */
{
xx = xx | 0xFF000000; /* Sign extend the sign bit */
}

yy = (TADC_DATA_24BIT & 0x00FFFFFF);/* Mask the upper 8 bits */
if(yy & 0x00800000) /* If sign bit is set */
{
yy = yy | 0xFF000000; /* Sign extend the sign bit */
}
#else
SL coeffP;

ADC_Count1++;

/* Accumulate the value of P channel */
FIR_AccadcValue[0] = PADC_DATA;
/* Accumulate the value of T channel */
FIR_AccadcValue[1] += TADC_DATA;

/* Update DAC with previous value */
if (FaultDiag == 0)
{
DAC_REG0 = DAC_Value;
}
else if (FaultDiag == 1)
{
DAC_REG0 = 0x0000;
}
else if (FaultDiag == 2)
{
DAC_REG0 = 0x0FFF;
}

/*
* Application specific Pcoefficient Calculation
* Dn = H + G * PADC/2^14 + N * (PADC/2^14)^2
* DAC = Dn
* Please refer compensation algorithm document.
*/
coeffP = (NtempCoeff[VarI] * FIR_AccadcValue[0]);
coeffP = (coeffP >> 14);
coeffP = coeffP + GtempCoeff[VarI];
coeffP = (coeffP * FIR_AccadcValue[0]);
coeffP = (coeffP >> 14);
coeffP = coeffP + HtempCoeff[VarI];
DAC_Value = (US)(coeffP);
#endif
}

This is a example of PGA900 Generic Firmware .ADC Interrupt get ad and pass it's value to second order function.what the red code mean? why that code is not as follow?

example 1:

/* Accumulate the value of P channel */
FIR_AccadcValue[0] = PADC_DATA;
/* Accumulate the value of T channel */
FIR_AccadcValue[1] = TADC_DATA;

example 2:

/* Accumulate the value of P channel */
FIR_AccadcValue[0] += PADC_DATA;
/* Accumulate the value of T channel */
FIR_AccadcValue[1] += TADC_DATA;

over 5 years ago

0 Scott Cummins over 5 years ago

TI__Mastermind 31655 points

Hello,

It really depends on how you would like to implement this. Everything here was just placed there as an example. In this case you are correct that the values don't actually accumulate how it is currently written. You could accumulate indefinitely, or you could accumulate a certain number of values before resetting back to 0.

For example:

if(TADC_AccIndex < 16)
       {
    	   FIR_AccadcValue[1] += (TADC_data_temp);		/* Accumulate 16 TADC Values for Temp. Calibration */
    	   TADC_AccIndex++;
       }
       else
       {
    	   TADC_AccValue = FIR_AccadcValue[1];
           FIR_AccadcValue[1] = 0;
           TADC_AccIndex = 0;

Again, this is entirely up to you and your application. It will work fine with a single value.

Regards,

Sensors

Sensors forum

CCS/PGA900EVM: pga900EVM