AD5941 Impedance Frequency Sweep without the Sequencer and Interrupts

Hi bmk521 ,

We will look into this. I will contact the product owner and get back to you.

Regards,

JC

Hi,

You will have to add 

AppIMPDataProcess((int32_t*)pBuff,&FifoCnt); 

function inside AD5940_Main() before 

ImpedanceShowResult(AppBuffImpedance, temp,++counter); function.

/* Depending on the data type, do appropriate data pre-process before return back to controller */
int32_t AppIMPDataProcess(int32_t * const pData, uint32_t *pDataCount)
{
  uint32_t DataCount = *pDataCount;
  uint32_t ImpResCount = DataCount/4;

  fImpPol_Type * const pOut = (fImpPol_Type*)pData;
  iImpCar_Type * pSrcData = (iImpCar_Type*)pData;

  *pDataCount = 0;

  DataCount = (DataCount/4)*4;/* We expect RCAL data together with Rz data. One DFT result has two data in FIFO, real part and imaginary part.  */

  /* Convert DFT result to int32_t type */
  for(uint32_t i=0; i<DataCount; i++)
  {
    pData[i] &= 0x3ffff; /* @todo option to check ECC */
    if(pData[i]&(1L<<17)) /* Bit17 is sign bit */
    {
      pData[i] |= 0xfffc0000; /* Data is 18bit in two's complement, bit17 is the sign bit */
    }
  }
  for(uint32_t i=0; i<ImpResCount; i++)
  {
    iImpCar_Type *pDftRcal, *pDftRz;

    pDftRcal = pSrcData++;
    pDftRz = pSrcData++;
    float RzMag,RzPhase;
    float RcalMag, RcalPhase;
    
    RcalMag = sqrt((float)pDftRcal->Real*pDftRcal->Real+(float)pDftRcal->Image*pDftRcal->Image);
    RcalPhase = atan2(-pDftRcal->Image,pDftRcal->Real);
    RzMag = sqrt((float)pDftRz->Real*pDftRz->Real+(float)pDftRz->Image*pDftRz->Image);
    RzPhase = atan2(-pDftRz->Image,pDftRz->Real);

    RzMag = RcalMag/RzMag*AppIMPCfg.RcalVal;
    RzPhase = RcalPhase - RzPhase;
    //printf("V:%d,%d,I:%d,%d ",pDftRcal->Real,pDftRcal->Image, pDftRz->Real, pDftRz->Image);
    
    pOut[i].Magnitude = RzMag;
    pOut[i].Phase = RzPhase;
  }
  *pDataCount = ImpResCount; 
  AppIMPCfg.FreqofData = AppIMPCfg.SweepCurrFreq;
  /* Calculate next frequency point */
  if(AppIMPCfg.SweepCfg.SweepEn == bTRUE)
  {
    AppIMPCfg.FreqofData = AppIMPCfg.SweepCurrFreq;
    AppIMPCfg.SweepCurrFreq = AppIMPCfg.SweepNextFreq;
    AD5940_SweepNext(&AppIMPCfg.SweepCfg, &AppIMPCfg.SweepNextFreq);
  }

  return 0;
}

Output data is stored in pOut[].

Hi Akila thanks for the response. This makes sense, thanks. 

When you call AppIMPDataProcess((int32_t*)pBuff,&FifoCnt); in the AD5940_main, where is the &FifoCnt coming from? If I am correct, the pBuff is a pointer to the AppBuffImpedance declared earlier in the C file(see below).

#define APPBUFF_SIZE_IMPEDANCE 512
uint32_t AppBuffImpedance[APPBUFF_SIZE_IMPEDANCE];
uint64_t counter = 0;

FifoCnt = (AD5940_FIFOGetCnt()/4)*4;

Yes. (int32_t*)pBuff is

#define APPBUFF_SIZE 512
uint32_t AppBuff[APPBUFF_SIZE];