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AD5941 Can AD594x continuously and simultaneously generate a sine wave and process the data via ADC? if yes, can I have the code in BIA formation, please?

Category: Software
Product Number: AD5941
Software Version: AD5940 EXAMPLES

Referring to this question:

 is there way to use ad5940 without interrupt or GPIO interrupt pin? 

I'm not sure if the author ever got it to work, anyway, so I have a requirement to generate the sinewave of programmable freq continuously in BIA setup (4 wire setup), and continuously get the ADC data, not stopping ever, till I manually stop it.

The current BIA example uses a sequencer, and the WG stops and starts all the time, as I cheded on the oscilloscope. I'm okay with the interrupt to trigger to notify if the data is ready, but not sure if I should use the sequencer? I tried to write the example myself without the sequencer, but it didn't work, and hence I'm here asking for help.

So, here's a question: Can AD594x continuously and simultaneously generate a sine wave and process the data via ADC? if yes, can I have the code in BIA formation, please?

Parents
  • Hi,

    You may just remove the sleep command from all sequences in BIA code.

    That is remove the below line wherever it is called:

    AD5940_EnterSleepS();

    Also inside measure sequence, WG block is turned off. You may remove the red part below:

    AD5940_AFECtrlS(AFECTRL_ADCCNV|AFECTRL_DFT|AFECTRL_WG|AFECTRL_ADCPWR, bFALSE);  /* Stop ADC convert and DFT */

  • Thanks for the reply. I implemented the changes, however, the WG stops/starts frequently, please see the attached screenshot. Could you share the code that you got it to work?

  • Hi,

    With the below code:

    *********
    // @file:    BodyComposition.c
    *****/
    #include "BodyImpedance.h"
    
    
    AppBIACfg_Type AppBIACfg = 
    {
      .bParaChanged = bFALSE,
      .SeqStartAddr = 0,
      .MaxSeqLen = 0,
      
      .SeqStartAddrCal = 0,
      .MaxSeqLenCal = 0,
    
      .ReDoRtiaCal = bFALSE,
      .SysClkFreq = 16000000.0,
      .WuptClkFreq = 32000.0,
      .AdcClkFreq = 16000000.0,
      .BiaODR = 20.0, /* 20.0 Hz*/
      .NumOfData = -1,
      .RcalVal = 10000.0, /* 10kOhm */
    
      .PwrMod = AFEPWR_LP,
      .HstiaRtiaSel = HSTIARTIA_1K,
      .CtiaSel = 16,
      .ExcitBufGain = EXCITBUFGAIN_2,
      .HsDacGain = HSDACGAIN_1,
      .HsDacUpdateRate = 7,
      .DacVoltPP = 800.0,
    
      .SinFreq = 50000.0, /* 50kHz */
    
      .ADCPgaGain = ADCPGA_1,
      .ADCSinc3Osr = ADCSINC3OSR_2,
      .ADCSinc2Osr = ADCSINC2OSR_22,
    
      .DftNum = DFTNUM_8192,
      .DftSrc = DFTSRC_SINC3,
      .HanWinEn = bTRUE,
    
      .SweepCfg.SweepEn = bFALSE,
      .SweepCfg.SweepStart = 10000,
      .SweepCfg.SweepStop = 150000.0,
      .SweepCfg.SweepPoints = 100,
      .SweepCfg.SweepLog = bTRUE,
      .SweepCfg.SweepIndex = 0,
    
      .FifoThresh = 4,
      .BIAInited = bFALSE,
      .StopRequired = bFALSE,
      .MeasSeqCycleCount = 0,
    };
    
    /**
       This function is provided for upper controllers that want to change 
       application parameters specially for user defined parameters.
    */
    AD5940Err AppBIAGetCfg(void *pCfg)
    {
      if(pCfg){
        *(AppBIACfg_Type**)pCfg = &AppBIACfg;
        return AD5940ERR_OK;
      }
      return AD5940ERR_PARA;
    }
    
    AD5940Err AppBIACtrl(int32_t BcmCtrl, void *pPara)
    {
      switch (BcmCtrl)
      {
        case BIACTRL_START:
        {
          WUPTCfg_Type wupt_cfg;
          if(AD5940_WakeUp(10) > 10)  /* Wakeup AFE by read register, read 10 times at most */
            return AD5940ERR_WAKEUP;  /* Wakeup Failed */
          if(AppBIACfg.BIAInited == bFALSE)
            return AD5940ERR_APPERROR;
          /* Start it */
          wupt_cfg.WuptEn = bTRUE;
          wupt_cfg.WuptEndSeq = WUPTENDSEQ_A;
          wupt_cfg.WuptOrder[0] = SEQID_0;
          wupt_cfg.SeqxSleepTime[SEQID_0] = (uint32_t)(AppBIACfg.WuptClkFreq/AppBIACfg.BiaODR)-2-1;
          wupt_cfg.SeqxWakeupTime[SEQID_0] = 1; /* The minimum value is 1. Do not set it to zero. Set it to 1 will spend 2 32kHz clock. */
          AD5940_WUPTCfg(&wupt_cfg);
          
          AppBIACfg.FifoDataCount = 0;  /* restart */
          break;
        }
        case BIACTRL_STOPNOW:
        {
          if(AD5940_WakeUp(10) > 10)  /* Wakeup AFE by read register, read 10 times at most */
            return AD5940ERR_WAKEUP;  /* Wakeup Failed */
          /* Start Wupt right now */
          AD5940_WUPTCtrl(bFALSE);
          /* There is chance this operation will fail because sequencer could put AFE back 
            to hibernate mode just after waking up. Use STOPSYNC is better. */
          AD5940_WUPTCtrl(bFALSE);
          break;
        }
        case BIACTRL_STOPSYNC:
        {
          AppBIACfg.StopRequired = bTRUE;
          break;
        }
        case BIACTRL_GETFREQ:
        if(pPara)
        {
          if(AppBIACfg.SweepCfg.SweepEn == bTRUE)
            *(float*)pPara = AppBIACfg.FreqofData;
          else
            *(float*)pPara = AppBIACfg.SinFreq;
        }
        break;
        case BIACTRL_SHUTDOWN:
        {
          AppBIACtrl(BIACTRL_STOPNOW, 0);  /* Stop the measurement if it's running. */
          /* Turn off LPloop related blocks which are not controlled automatically by sleep operation */
          AFERefCfg_Type aferef_cfg;
          LPLoopCfg_Type lp_loop;
          memset(&aferef_cfg, 0, sizeof(aferef_cfg));
          AD5940_REFCfgS(&aferef_cfg);
          memset(&lp_loop, 0, sizeof(lp_loop));
          AD5940_LPLoopCfgS(&lp_loop);
          AD5940_EnterSleepS();  /* Enter Hibernate */
        }
        break;
        default:
        break;
      }
      return AD5940ERR_OK;
    }
    
    /* Generate init sequence */
    static AD5940Err AppBIASeqCfgGen(void)
    {
      AD5940Err error = AD5940ERR_OK;
      uint32_t const *pSeqCmd;
      uint32_t SeqLen;
    
      AFERefCfg_Type aferef_cfg;
      HSLoopCfg_Type hs_loop;
      LPLoopCfg_Type lp_loop;
      DSPCfg_Type dsp_cfg;
      float sin_freq;
    
      /* Start sequence generator here */
      AD5940_SEQGenCtrl(bTRUE);
    
      //AD5940_AFECtrlS(AFECTRL_ALL, bFALSE);  /* Init all to disable state */
    
      aferef_cfg.HpBandgapEn = bTRUE;
      aferef_cfg.Hp1V1BuffEn = bTRUE;
      aferef_cfg.Hp1V8BuffEn = bTRUE;
      aferef_cfg.Disc1V1Cap = bFALSE;
      aferef_cfg.Disc1V8Cap = bFALSE;
      aferef_cfg.Hp1V8ThemBuff = bFALSE;
      aferef_cfg.Hp1V8Ilimit = bFALSE;
      aferef_cfg.Lp1V1BuffEn = bFALSE;
      aferef_cfg.Lp1V8BuffEn = bFALSE;
      /* LP reference control - turn off them to save power*/
      aferef_cfg.LpBandgapEn = bTRUE;
      aferef_cfg.LpRefBufEn = bTRUE;
      aferef_cfg.LpRefBoostEn = bFALSE;
      AD5940_REFCfgS(&aferef_cfg);	
      hs_loop.HsDacCfg.ExcitBufGain = AppBIACfg.ExcitBufGain;
      hs_loop.HsDacCfg.HsDacGain = AppBIACfg.HsDacGain;
      hs_loop.HsDacCfg.HsDacUpdateRate = AppBIACfg.HsDacUpdateRate;
    
      hs_loop.HsTiaCfg.DiodeClose = bFALSE;
      hs_loop.HsTiaCfg.HstiaBias = HSTIABIAS_1P1;
      hs_loop.HsTiaCfg.HstiaCtia = AppBIACfg.CtiaSel; /* 31pF + 2pF */
      hs_loop.HsTiaCfg.HstiaDeRload = HSTIADERLOAD_OPEN;
      hs_loop.HsTiaCfg.HstiaDeRtia = HSTIADERTIA_OPEN;
      hs_loop.HsTiaCfg.HstiaRtiaSel = AppBIACfg.HstiaRtiaSel;
    
      hs_loop.SWMatCfg.Dswitch = SWD_OPEN;
      hs_loop.SWMatCfg.Pswitch = SWP_PL|SWP_PL2;
      hs_loop.SWMatCfg.Nswitch = SWN_NL|SWN_NL2;
      hs_loop.SWMatCfg.Tswitch = SWT_TRTIA;
    
      hs_loop.WgCfg.WgType = WGTYPE_SIN;
      hs_loop.WgCfg.GainCalEn = bFALSE;
      hs_loop.WgCfg.OffsetCalEn = bFALSE;
      if(AppBIACfg.SweepCfg.SweepEn == bTRUE)
      {
    		AppBIACfg.SweepCfg.SweepIndex = 0;
        AppBIACfg.FreqofData = AppBIACfg.SweepCfg.SweepStart;
        AppBIACfg.SweepCurrFreq = AppBIACfg.SweepCfg.SweepStart;
        AD5940_SweepNext(&AppBIACfg.SweepCfg, &AppBIACfg.SweepNextFreq);
        sin_freq = AppBIACfg.SweepCurrFreq;
      }
      else
      {
        sin_freq = AppBIACfg.SinFreq;
        AppBIACfg.FreqofData = sin_freq;
      }
      hs_loop.WgCfg.SinCfg.SinFreqWord = AD5940_WGFreqWordCal(sin_freq, AppBIACfg.SysClkFreq);
      hs_loop.WgCfg.SinCfg.SinAmplitudeWord = (uint32_t)(AppBIACfg.DacVoltPP/800.0f*2047 + 0.5f);
      hs_loop.WgCfg.SinCfg.SinOffsetWord = 0;
      hs_loop.WgCfg.SinCfg.SinPhaseWord = 0;
      AD5940_HSLoopCfgS(&hs_loop);
    
      lp_loop.LpDacCfg.LpdacSel = LPDAC0;
      lp_loop.LpDacCfg.LpDacSrc = LPDACSRC_MMR;
      lp_loop.LpDacCfg.LpDacSW = LPDACSW_VBIAS2LPPA|LPDACSW_VBIAS2PIN|LPDACSW_VZERO2LPTIA|LPDACSW_VZERO2PIN;
      lp_loop.LpDacCfg.LpDacVzeroMux = LPDACVZERO_6BIT;
      lp_loop.LpDacCfg.LpDacVbiasMux = LPDACVBIAS_12BIT;
      lp_loop.LpDacCfg.LpDacRef = LPDACREF_2P5;
      lp_loop.LpDacCfg.DataRst = bFALSE;
      lp_loop.LpDacCfg.PowerEn = bTRUE;
      lp_loop.LpDacCfg.DacData12Bit = (uint32_t)((1100-200)/2200.0*4095);
      lp_loop.LpDacCfg.DacData6Bit = 31;
    
      lp_loop.LpAmpCfg.LpAmpSel = LPAMP0;
      lp_loop.LpAmpCfg.LpAmpPwrMod = LPAMPPWR_NORM;
      lp_loop.LpAmpCfg.LpPaPwrEn = bTRUE;
      lp_loop.LpAmpCfg.LpTiaPwrEn = bTRUE;
      lp_loop.LpAmpCfg.LpTiaRf = LPTIARF_20K;
      lp_loop.LpAmpCfg.LpTiaRload = LPTIARLOAD_SHORT;
      lp_loop.LpAmpCfg.LpTiaRtia = LPTIARTIA_OPEN;
      lp_loop.LpAmpCfg.LpTiaSW = LPTIASW(5)|LPTIASW(6)|LPTIASW(7)|LPTIASW(8)|LPTIASW(9)|LPTIASW(12)|LPTIASW(13); /** @todo Optimization needed for new silicon */
      AD5940_LPLoopCfgS(&lp_loop);
    
      dsp_cfg.ADCBaseCfg.ADCMuxN = ADCMUXN_HSTIA_N;
      dsp_cfg.ADCBaseCfg.ADCMuxP = ADCMUXP_HSTIA_P;
      dsp_cfg.ADCBaseCfg.ADCPga = AppBIACfg.ADCPgaGain;
      
      memset(&dsp_cfg.ADCDigCompCfg, 0, sizeof(dsp_cfg.ADCDigCompCfg));
      
      dsp_cfg.ADCFilterCfg.ADCAvgNum = ADCAVGNUM_16;  /* Don't care because it's disabled */
      dsp_cfg.ADCFilterCfg.ADCRate = ADCRATE_800KHZ;	/* Tell filter block clock rate of ADC*/
      dsp_cfg.ADCFilterCfg.ADCSinc2Osr = AppBIACfg.ADCSinc2Osr;
      dsp_cfg.ADCFilterCfg.ADCSinc3Osr = AppBIACfg.ADCSinc3Osr;
      dsp_cfg.ADCFilterCfg.BpSinc3 = bFALSE;
      dsp_cfg.ADCFilterCfg.BpNotch = bTRUE;
      dsp_cfg.ADCFilterCfg.Sinc2NotchEnable = bTRUE;
      dsp_cfg.DftCfg.DftNum = AppBIACfg.DftNum;
      dsp_cfg.DftCfg.DftSrc = AppBIACfg.DftSrc;
      dsp_cfg.DftCfg.HanWinEn = AppBIACfg.HanWinEn;
      
      memset(&dsp_cfg.StatCfg, 0, sizeof(dsp_cfg.StatCfg)); /* Don't care about Statistic */
      AD5940_DSPCfgS(&dsp_cfg);
        
      /* Enable all of them. They are automatically turned off during hibernate mode to save power */
      AD5940_AFECtrlS(AFECTRL_HPREFPWR|AFECTRL_HSTIAPWR|AFECTRL_INAMPPWR|AFECTRL_EXTBUFPWR|\
                    AFECTRL_WG|AFECTRL_DACREFPWR|AFECTRL_HSDACPWR|\
                    AFECTRL_SINC2NOTCH, bTRUE);
      AD5940_SEQGpioCtrlS(0/*AGPIO_Pin6|AGPIO_Pin5|AGPIO_Pin1*/);        //GP6->endSeq, GP5 -> AD8233=OFF, GP1->RLD=OFF .
      
      /* Sequence end. */
      AD5940_SEQGenInsert(SEQ_STOP()); /* Add one extra command to disable sequencer for initialization sequence because we only want it to run one time. */
    
      /* Stop here */
      error = AD5940_SEQGenFetchSeq(&pSeqCmd, &SeqLen);
      AD5940_SEQGenCtrl(bFALSE); /* Stop sequencer generator */
      if(error == AD5940ERR_OK)
      {
        AppBIACfg.InitSeqInfo.SeqId = SEQID_1;
        AppBIACfg.InitSeqInfo.SeqRamAddr = AppBIACfg.SeqStartAddr;
        AppBIACfg.InitSeqInfo.pSeqCmd = pSeqCmd;
        AppBIACfg.InitSeqInfo.SeqLen = SeqLen;
        /* Write command to SRAM */
        AD5940_SEQCmdWrite(AppBIACfg.InitSeqInfo.SeqRamAddr, pSeqCmd, SeqLen);
      }
      else
        return error; /* Error */
      return AD5940ERR_OK;
    }
    
    
    
    static AD5940Err AppBIARtiaCal(void)
    {
      HSRTIACal_Type hsrtia_cal;
    
      hsrtia_cal.AdcClkFreq = AppBIACfg.AdcClkFreq;
      hsrtia_cal.ADCSinc2Osr = AppBIACfg.ADCSinc2Osr;
      hsrtia_cal.ADCSinc3Osr = AppBIACfg.ADCSinc3Osr;
      hsrtia_cal.bPolarResult = bTRUE; /* We need magnitude and phase here */
      hsrtia_cal.DftCfg.DftNum = AppBIACfg.DftNum;
      hsrtia_cal.DftCfg.DftSrc = AppBIACfg.DftSrc;
      hsrtia_cal.DftCfg.HanWinEn = AppBIACfg.HanWinEn;
      hsrtia_cal.fRcal= AppBIACfg.RcalVal;
      hsrtia_cal.HsTiaCfg.DiodeClose = bFALSE;
      hsrtia_cal.HsTiaCfg.HstiaBias = HSTIABIAS_1P1;
      hsrtia_cal.HsTiaCfg.HstiaCtia = AppBIACfg.CtiaSel;
      hsrtia_cal.HsTiaCfg.HstiaDeRload = HSTIADERLOAD_OPEN;
      hsrtia_cal.HsTiaCfg.HstiaDeRtia = HSTIADERTIA_TODE;
      hsrtia_cal.HsTiaCfg.HstiaRtiaSel = AppBIACfg.HstiaRtiaSel;
      hsrtia_cal.SysClkFreq = AppBIACfg.SysClkFreq;
      hsrtia_cal.fFreq = AppBIACfg.SweepCfg.SweepStart;
    
      if(AppBIACfg.SweepCfg.SweepEn == bTRUE)
      {
        uint32_t i;
        AppBIACfg.SweepCfg.SweepIndex = 0;  /* Reset index */
        for(i=0;i<AppBIACfg.SweepCfg.SweepPoints;i++)
        {
    			AD5940_HSRtiaCal(&hsrtia_cal, AppBIACfg.RtiaCalTable[i]);
    #ifdef ADI_DEBUG
          ADI_Print("Freq:%.2f, RTIA: Mag:%f Ohm, Phase:%.3f\n", hsrtia_cal.fFreq, AppBIACfg.RtiaCalTable[i][0], AppBIACfg.RtiaCalTable[i][1]);
    #endif
          AD5940_SweepNext(&AppBIACfg.SweepCfg, &hsrtia_cal.fFreq);     
        }
        AppBIACfg.SweepCfg.SweepIndex = 0;  /* Reset index */
        AppBIACfg.RtiaCurrValue[0] = AppBIACfg.RtiaCalTable[AppBIACfg.SweepCfg.SweepIndex][0];
        AppBIACfg.RtiaCurrValue[1] = AppBIACfg.RtiaCalTable[AppBIACfg.SweepCfg.SweepIndex][1];
        
      }
      else
      {
        hsrtia_cal.fFreq = AppBIACfg.SinFreq;
        AD5940_HSRtiaCal(&hsrtia_cal, AppBIACfg.RtiaCurrValue);
      }
      return AD5940ERR_OK;
    }
    static AD5940Err Measure(void)
    {
      SWMatrixCfg_Type sw_cfg;
      sw_cfg.Dswitch = SWD_CE0;
      sw_cfg.Pswitch = SWP_CE0;
      sw_cfg.Nswitch = SWN_AIN1;
      sw_cfg.Tswitch = SWT_AIN1|SWT_TRTIA;
      AD5940_SWMatrixCfgS(&sw_cfg);
    uint32_t WaitClks;
      ClksCalInfo_Type clks_cal;
      
      clks_cal.DataType = DATATYPE_DFT;
      clks_cal.DftSrc = AppBIACfg.DftSrc;
      clks_cal.DataCount = 1L<<(AppBIACfg.DftNum+2); /* 2^(DFTNUMBER+2) */
      clks_cal.ADCSinc2Osr = AppBIACfg.ADCSinc2Osr;
      clks_cal.ADCSinc3Osr = AppBIACfg.ADCSinc3Osr;
      clks_cal.ADCAvgNum = 0;
      clks_cal.RatioSys2AdcClk = AppBIACfg.SysClkFreq/AppBIACfg.AdcClkFreq;
      AD5940_ClksCalculate(&clks_cal, &WaitClks);
      AD5940_AGPIOClr(AGPIO_Pin2);
      
      AD5940_ADCMuxCfgS(ADCMUXP_HSTIA_P, ADCMUXN_HSTIA_N);
      AD5940_AFECtrlS(AFECTRL_WG|AFECTRL_ADCPWR, bTRUE);  /* Enable Waveform generator, ADC power */
      AD5940_Delay10us(16*50);
      AD5940_AFECtrlS(AFECTRL_ADCCNV|AFECTRL_DFT, bTRUE);  /* Start ADC convert and DFT */
      AD5940_Delay10us(Waitclks); /* wait for first data ready */  
      //AD5940_AFECtrlS(AFECTRL_ADCCNV|AFECTRL_DFT|AFECTRL_WG|AFECTRL_ADCPWR, bFALSE);  /* Stop ADC convert and DFT */
      AD5940_AFECtrlS(AFECTRL_ADCCNV|AFECTRL_DFT|AFECTRL_ADCPWR, bFALSE);  /* Stop ADC convert and DFT */
    
      AD5940_ADCMuxCfgS(ADCMUXP_AIN3, ADCMUXN_AIN2);
      //AD5940_AFECtrlS(AFECTRL_WG|AFECTRL_ADCPWR, bTRUE);  /* Enable Waveform generator, ADC power */
      AD5940_AFECtrlS(AFECTRL_ADCPWR, bTRUE);  /* Enable Waveform generator, ADC power */
      AD5940_Delay10us(16*50);  //delay for signal settling DFT_WAIT
      AD5940_AFECtrlS(AFECTRL_ADCCNV|AFECTRL_DFT, bTRUE);  /* Start ADC convert and DFT */
      AD5940_Delay10us(Waitclks);  /* wait for first data ready */
      //AD5940_AFECtrlS(AFECTRL_ADCCNV|AFECTRL_DFT|AFECTRL_WG|AFECTRL_ADCPWR, bFALSE);  /* Stop ADC convert and DFT */
       AD5940_AFECtrlS(AFECTRL_ADCCNV|AFECTRL_DFT|AFECTRL_ADCPWR, bFALSE);  /* Stop ADC convert and DFT */
      
      sw_cfg.Dswitch = SWD_OPEN;
      sw_cfg.Pswitch = SWP_PL|SWP_PL2;
      sw_cfg.Nswitch = SWN_NL|SWN_NL2;
      sw_cfg.Tswitch = SWT_TRTIA;
      AD5940_SWMatrixCfgS(&sw_cfg); /* Float switches */
      AD5940_AGPIOSet(AGPIO_Pin2);
       return AD5940ERR_OK;
    }
    
    /* This function provide application initialize.   */
    AD5940Err AppBIAInit(uint32_t *pBuffer, uint32_t BufferSize)
    {
      AD5940Err error = AD5940ERR_OK;
      SEQCfg_Type seq_cfg;
      FIFOCfg_Type fifo_cfg;
    
      if(AD5940_WakeUp(10) > 10)  /* Wakeup AFE by read register, read 10 times at most */
        return AD5940ERR_WAKEUP;  /* Wakeup Failed */
    
      /* Configure sequencer and stop it */
      seq_cfg.SeqMemSize = SEQMEMSIZE_2KB;  /* 2kB SRAM is used for sequencer, others for data FIFO */
      seq_cfg.SeqBreakEn = bFALSE;
      seq_cfg.SeqIgnoreEn = bFALSE;
      seq_cfg.SeqCntCRCClr = bTRUE;
      seq_cfg.SeqEnable = bFALSE;
      seq_cfg.SeqWrTimer = 0;
      AD5940_SEQCfg(&seq_cfg);
    
      /* Do RTIA calibration */
      
      if((AppBIACfg.ReDoRtiaCal == bTRUE) || \
          AppBIACfg.BIAInited == bFALSE)  /* Do calibration on the first initializaion */
      {
        AppBIARtiaCal();
        AppBIACfg.ReDoRtiaCal = bFALSE;
      }
      /* Reconfigure FIFO */
      AD5940_FIFOCtrlS(FIFOSRC_DFT, bFALSE);									/* Disable FIFO firstly */
      fifo_cfg.FIFOEn = bTRUE;
      fifo_cfg.FIFOMode = FIFOMODE_FIFO;
      fifo_cfg.FIFOSize = FIFOSIZE_4KB;                       /* 4kB for FIFO, The reset 2kB for sequencer */
      fifo_cfg.FIFOSrc = FIFOSRC_DFT;
      fifo_cfg.FIFOThresh = AppBIACfg.FifoThresh;              /* DFT result. One pair for RCAL, another for Rz. One DFT result have real part and imaginary part */
      AD5940_FIFOCfg(&fifo_cfg);
    
      AD5940_INTCClrFlag(AFEINTSRC_ALLINT);
      
      /* Start sequence generator */
      /* Initialize sequencer generator */
      if((AppBIACfg.BIAInited == bFALSE)||\
           (AppBIACfg.bParaChanged == bTRUE))
      {
        if(pBuffer == 0)  return AD5940ERR_PARA;
        if(BufferSize == 0) return AD5940ERR_PARA;   
        AD5940_SEQGenInit(pBuffer, BufferSize);
    
        /* Generate initialize sequence */
        error = AppBIASeqCfgGen(); /* Application initialization sequence using either MCU or sequencer */
        if(error != AD5940ERR_OK) return error;
    
        AppBIACfg.bParaChanged = bFALSE; /* Clear this flag as we already implemented the new configuration */
      }
    
      /* Initialization sequencer  */
      AppBIACfg.InitSeqInfo.WriteSRAM = bFALSE;
      AD5940_SEQInfoCfg(&AppBIACfg.InitSeqInfo);
      seq_cfg.SeqEnable = bTRUE;
      AD5940_SEQCfg(&seq_cfg);  /* Enable sequencer */
      AD5940_SEQMmrTrig(AppBIACfg.InitSeqInfo.SeqId);
      while(AD5940_INTCTestFlag(AFEINTC_1, AFEINTSRC_ENDSEQ) == bFALSE);
      
         while(AD5940_INTCTestFlag(AFEINTC_0, AFEINTSRC_DATAFIFOTHRESH) == bFALSE)
          {
          Measure();
          }
        
     // AD5940_ClrMCUIntFlag();   /* Clear interrupt flag generated before */
    
      AD5940_AFEPwrBW(AppBIACfg.PwrMod, AFEBW_250KHZ);
      AD5940_WriteReg(REG_AFE_SWMUX, 1<<3);
      AppBIACfg.BIAInited = bTRUE;  /* BIA application has been initialized. */
      return AD5940ERR_OK;
    }
    
    /* Modify registers when AFE wakeup */
    static AD5940Err AppBIARegModify(int32_t * const pData, uint32_t *pDataCount)
    {
      if(AppBIACfg.NumOfData > 0)
      {
        AppBIACfg.FifoDataCount += *pDataCount/4;
        if(AppBIACfg.FifoDataCount >= AppBIACfg.NumOfData)
        {
          AD5940_WUPTCtrl(bFALSE);
          return AD5940ERR_OK;
        }
      }
      if(AppBIACfg.StopRequired == bTRUE)
      {
        AD5940_WUPTCtrl(bFALSE);
        return AD5940ERR_OK;
      }
      if(AppBIACfg.SweepCfg.SweepEn) /* Need to set new frequency and set power mode */
      {
        AD5940_WGFreqCtrlS(AppBIACfg.SweepNextFreq, AppBIACfg.SysClkFreq);
      }
      return AD5940ERR_OK;
    }
    
    /* Depending on the data type, do appropriate data pre-process before return back to controller */
    static AD5940Err AppBIADataProcess(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]&(1<<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 *pDftVolt, *pDftCurr;
    
        pDftCurr = pSrcData++;
        pDftVolt = pSrcData++;
        float VoltMag,VoltPhase;
        float CurrMag, CurrPhase;
    
        VoltMag = sqrt((float)pDftVolt->Real*pDftVolt->Real+(float)pDftVolt->Image*pDftVolt->Image);
        VoltPhase = atan2(-pDftVolt->Image,pDftVolt->Real);
        CurrMag = sqrt((float)pDftCurr->Real*pDftCurr->Real+(float)pDftCurr->Image*pDftCurr->Image);
        CurrPhase = atan2(-pDftCurr->Image,pDftCurr->Real);
    
        VoltMag = VoltMag/CurrMag*AppBIACfg.RtiaCurrValue[0];
        VoltPhase = VoltPhase - CurrPhase + AppBIACfg.RtiaCurrValue[1];
    
        pOut[i].Magnitude = VoltMag;
        pOut[i].Phase = VoltPhase;
      }
      *pDataCount = ImpResCount; 
      /* Calculate next frequency point */
      if(AppBIACfg.SweepCfg.SweepEn == bTRUE)
      {
        AppBIACfg.FreqofData = AppBIACfg.SweepCurrFreq;
        AppBIACfg.SweepCurrFreq = AppBIACfg.SweepNextFreq;
    		AppBIACfg.RtiaCurrValue[0] = AppBIACfg.RtiaCalTable[AppBIACfg.SweepCfg.SweepIndex][0];
        AppBIACfg.RtiaCurrValue[1] = AppBIACfg.RtiaCalTable[AppBIACfg.SweepCfg.SweepIndex][1];
        AD5940_SweepNext(&AppBIACfg.SweepCfg, &AppBIACfg.SweepNextFreq);
      }
      return AD5940ERR_OK;
    }
    
    
    
    /**
    */
    AD5940Err AppBIAISR(void *pBuff, uint32_t *pCount)
    {
      uint32_t BuffCount;
      uint32_t FifoCnt;
      BuffCount = *pCount;
      if(AppBIACfg.BIAInited == bFALSE)
        return AD5940ERR_APPERROR;
     // if(AD5940_WakeUp(10) > 10)  /* Wakeup AFE by read register, read 10 times at most */
      //  return AD5940ERR_WAKEUP;  /* Wakeup Failed */
      AD5940_SleepKeyCtrlS(SLPKEY_LOCK);  /* Don't enter hibernate */
      *pCount = 0;
    
      if(AD5940_INTCTestFlag(AFEINTC_0, AFEINTSRC_DATAFIFOTHRESH) == bTRUE)
      {
        /* Now there should be 4 data in FIFO */
        FifoCnt = (AD5940_FIFOGetCnt()/4)*4;
        
        if(FifoCnt > BuffCount)
        {
          ///@todo buffer is limited.
        }
        AD5940_FIFORd((uint32_t *)pBuff, FifoCnt);
        AD5940_INTCClrFlag(AFEINTSRC_DATAFIFOTHRESH);
        AppBIARegModify(pBuff, &FifoCnt);   /* If there is need to do AFE re-configure, do it here when AFE is in active state */
        //AD5940_EnterSleepS();  /* Manually put AFE back to hibernate mode. */
        AD5940_SleepKeyCtrlS(SLPKEY_UNLOCK);  /* Allow AFE to enter hibernate mode */
        /* Process data */ 
        AppBIADataProcess((int32_t*)pBuff,&FifoCnt); 
        *pCount = FifoCnt;
        while(AD5940_INTCTestFlag(AFEINTC_0, AFEINTSRC_DATAFIFOTHRESH) == bFALSE)
          {
          Measure();
          }
        return 0;
      }
      
      return 0;
    } 
    
    
    /**
      * @}
      */

    **********
     //@file:    AD5940Main.c
     ***********/
    /** 
     * @addtogroup AD5940_System_Examples
     * @{
     *  @defgroup BioElec_Example
     *  @{
      */
    #include "ad5940.h"
    #include "AD5940.h"
    #include <stdio.h>
    #include "string.h"
    #include "math.h"
    #include "BodyImpedance.h"
    
    #define APPBUFF_SIZE 512
    uint32_t AppBuff[APPBUFF_SIZE];
    
    /* It's your choice here how to do with the data. Here is just an example to print them to UART */
    int32_t BIAShowResult(uint32_t *pData, uint32_t DataCount)
    {
      float freq;
    
      fImpPol_Type *pImp = (fImpPol_Type*)pData;
      AppBIACtrl(BIACTRL_GETFREQ, &freq);
    
      printf("Freq:%.2f ", freq);
      /*Process data*/
      for(int i=0;i<DataCount;i++)
      {
        printf("RzMag: %f Ohm , RzPhase: %f \n",pImp[i].Magnitude,pImp[i].Phase*180/MATH_PI);
      }
      return 0;
    }
    
    /* Initialize AD5940 basic blocks like clock */
    static int32_t AD5940PlatformCfg(void)
    {
      CLKCfg_Type clk_cfg;
      FIFOCfg_Type fifo_cfg;
      AGPIOCfg_Type gpio_cfg;
    
      /* Use hardware reset */
      AD5940_HWReset();
      /* Platform configuration */
      AD5940_Initialize();
      /* Step1. Configure clock */
      clk_cfg.ADCClkDiv = ADCCLKDIV_1;
      clk_cfg.ADCCLkSrc = ADCCLKSRC_HFOSC;
      clk_cfg.SysClkDiv = SYSCLKDIV_1;
      clk_cfg.SysClkSrc = SYSCLKSRC_HFOSC;
      clk_cfg.HfOSC32MHzMode = bFALSE;
      clk_cfg.HFOSCEn = bTRUE;
      clk_cfg.HFXTALEn = bFALSE;
      clk_cfg.LFOSCEn = bTRUE;
      AD5940_CLKCfg(&clk_cfg);
      /* Step2. Configure FIFO and Sequencer*/
      fifo_cfg.FIFOEn = bFALSE;
      fifo_cfg.FIFOMode = FIFOMODE_FIFO;
      fifo_cfg.FIFOSize = FIFOSIZE_4KB;                       /* 4kB for FIFO, The reset 2kB for sequencer */
      fifo_cfg.FIFOSrc = FIFOSRC_DFT;
      fifo_cfg.FIFOThresh = 4;//AppBIACfg.FifoThresh;        /* DFT result. One pair for RCAL, another for Rz. One DFT result have real part and imaginary part */
      AD5940_FIFOCfg(&fifo_cfg);                             /* Disable to reset FIFO. */
      fifo_cfg.FIFOEn = bTRUE;  
      AD5940_FIFOCfg(&fifo_cfg);                             /* Enable FIFO here */
      
      /* Step3. Interrupt controller */
      
      AD5940_INTCCfg(AFEINTC_1, AFEINTSRC_ALLINT, bTRUE);           /* Enable all interrupt in Interrupt Controller 1, so we can check INTC flags */
      AD5940_INTCCfg(AFEINTC_0, AFEINTSRC_DATAFIFOTHRESH, bTRUE);   /* Interrupt Controller 0 will control GP0 to generate interrupt to MCU */
      AD5940_INTCClrFlag(AFEINTSRC_ALLINT);
      /* Step4: Reconfigure GPIO */
      gpio_cfg.FuncSet = GP6_SYNC|GP5_SYNC|GP4_SYNC|GP2_TRIG|GP1_SYNC|GP0_INT;
      gpio_cfg.InputEnSet = AGPIO_Pin2;
      gpio_cfg.OutputEnSet = AGPIO_Pin0|AGPIO_Pin1|AGPIO_Pin4|AGPIO_Pin5|AGPIO_Pin6;
      gpio_cfg.OutVal = 0;
      gpio_cfg.PullEnSet = 0;
    
      AD5940_AGPIOCfg(&gpio_cfg);
      AD5940_SleepKeyCtrlS(SLPKEY_UNLOCK);  /* Allow AFE to enter sleep mode. */
      return 0;
    }
    
    
    /* !!Change the application parameters here if you want to change it to none-default value */
    void AD5940BIAStructInit(void)
    {
      AppBIACfg_Type *pBIACfg;
      
      AppBIAGetCfg(&pBIACfg);
      
      pBIACfg->SeqStartAddr = 0;
      pBIACfg->MaxSeqLen = 512; /** @todo add checker in function */
      
      pBIACfg->RcalVal = 10000.0;
      pBIACfg->DftNum = DFTNUM_8192;
      pBIACfg->NumOfData = -1;      /* Never stop until you stop it manually by AppBIACtrl() function */
      pBIACfg->BiaODR = 20;         /* ODR(Sample Rate) 20Hz */
      pBIACfg->FifoThresh = 4;      /* 4 */
      pBIACfg->ADCSinc3Osr = ADCSINC3OSR_2;
    }
    
    void AD5940_Main(void)
    { 
      static uint32_t IntCount;
      static uint32_t count;
      
      uint32_t temp;
      
      AD5940PlatformCfg();
      
      AD5940BIAStructInit(); /* Configure your parameters in this function */
      
      AppBIAInit(AppBuff, APPBUFF_SIZE);    /* Initialize BIA application. Provide a buffer, which is used to store sequencer commands */
      //AppBIACtrl(BIACTRL_START, 0);         /* Control BIA measurement to start. Second parameter has no meaning with this command. */
      while(1)
      {
        /* Check if interrupt flag which will be set when interrupt occurred. */
        if(AD5940_INTCTestFlag(AFEINTC_0, AFEINTSRC_DATAFIFOTHRESH) == bTRUE)
      {
          IntCount++;
          AD5940_ClrMCUIntFlag(); /* Clear this flag */
          temp = APPBUFF_SIZE;
          AppBIAISR(AppBuff, &temp); /* Deal with it and provide a buffer to store data we got */
          BIAShowResult(AppBuff, temp); /* Show the results to UART */
    
          if(IntCount == 240)
          {
            IntCount = 0;
            //AppBIACtrl(BIACTRL_SHUTDOWN, 0);
          }
        }
        count++;
        if(count > 1000000)
        {
          count = 0;
          //AppBIAInit(0, 0);    /* Re-initialize BIA application. Because sequences are ready, no need to provide a buffer, which is used to store sequencer commands */
          //AppBIACtrl(BIACTRL_START, 0);          /* Control BIA measurement to start. Second parameter has no meaning with this command. */
        }
      }
    }
    
    /**
     * @}
     * @}
     * */
     
    

    I am able to get waveform across (CE0 - AIN1) as below:

  • Thanks for the reply, I implemented the above code, not only was I not getting the WG, but the ADC stopped working as well. There was a small typo in the code, and your attached figure shows it's not a sine wave, Im sorry am I missing something here?

    I also have a few questions regarding the code:

    1.  If the number of data points is -1 (AppBIACfg.NumOfData = -1;), why are we calling the Measure() function again in AppBIAISR()?

    2. Why are we stopping the ADC and DFT in the Measure function?

    AD5940_AFECtrlS(AFECTRL_ADCCNV|AFECTRL_DFT|AFECTRL_ADCPWR, bFALSE); /* Stop ADC convert and DFT */

    I wanted both the WG and ADC to go on till I manually pull the plug or send a stop command. For now I don't care for the power requirements, so might as well use high-power mode.

    3. Why are we floating the switches at the end of the Measure() function?

    If we are, there is no way we will get a continuous WG as we have floated the switches!

    4. Why are we toggling the GPIO_Pin2 in the Measure Function?

    5. Lastly, If we are not using the Sequencer for Measure function can we remove it entirely from the config function as well and thus from the code as well? I'm very happy to use SPI for everything,

  • Hi,

    Apologies for the typo.

    Infact, Waitclks must be scaled as below:

    AD5940_Delay10us(WaitClks/100); 

    instead of 

    AD5940_Delay10us(WaitClks);

    1) Since in the above code, wakeup timer is not used, measurement is not periodically triggered, Measure() need to be called for each measurement, hence called inside AppBIAISR().

    2) ADC must be turned on only for sampling the input. It should not be kept on always. Otherwise data fifo will be filled with junk data.

      In the above code, WG is kept on always.

    3) Floating switches after measurement is a good practice but optional. It is not reflected in the waveform captured above because switches are closed for a negligibly small duration.

    4) Toggling the GPIO_Pin2 helps check that measurement is happening and also to keep count of measurements, by monitoring GPIO2.

    5) Measure() is not using sequence in the above code as measurement is not required to be triggered by timer and sequence can run only at 32kHz clock.

    Hence its sequence is already removed in the above code.

    Below is the BIA measurement output I got for the above code for a 100 Ohm resistive load:

    Hello AD5940-Build Time:11:10:34
    Freq:50000.00 RzMag: 99.953804 Ohm , RzPhase: 1.029252 
    Freq:50000.00 RzMag: 99.953979 Ohm , RzPhase: 1.020536 
    Freq:50000.00 RzMag: 99.954971 Ohm , RzPhase: 1.018610 
    Freq:50000.00 RzMag: 99.958328 Ohm , RzPhase: 1.019177 
    Freq:50000.00 RzMag: 99.960709 Ohm , RzPhase: 1.021670 
    Freq:50000.00 RzMag: 99.958328 Ohm , RzPhase: 1.019177 
    Freq:50000.00 RzMag: 99.951485 Ohm , RzPhase: 1.041997 
    Freq:50000.00 RzMag: 99.960312 Ohm , RzPhase: 1.015318 
    Freq:50000.00 RzMag: 99.961296 Ohm , RzPhase: 1.013385 
    Freq:50000.00 RzMag: 99.960312 Ohm , RzPhase: 1.015318 
    Freq:50000.00 RzMag: 99.958328 Ohm , RzPhase: 1.019177 
    Freq:50000.00 RzMag: 99.958328 Ohm , RzPhase: 1.019177 
    Freq:50000.00 RzMag: 99.960709 Ohm , RzPhase: 1.021670 
    Freq:50000.00 RzMag: 99.952477 Ohm , RzPhase: 1.040064 
    Freq:50000.00 RzMag: 99.956947 Ohm , RzPhase: 1.014751 
    Freq:50000.00 RzMag: 99.961296 Ohm , RzPhase: 1.013385 
    Freq:50000.00 RzMag: 99.957932 Ohm , RzPhase: 1.012818 
    Freq:50000.00 RzMag: 99.955948 Ohm , RzPhase: 1.016677 
    Freq:50000.00 RzMag: 99.956947 Ohm , RzPhase: 1.014751 
    Freq:50000.00 RzMag: 99.956947 Ohm , RzPhase: 1.014751 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.957932 Ohm , RzPhase: 1.012818 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.947716 Ohm , RzPhase: 1.035071 
    Freq:50000.00 RzMag: 99.957932 Ohm , RzPhase: 1.012818 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.956947 Ohm , RzPhase: 1.014751 
    Freq:50000.00 RzMag: 99.946732 Ohm , RzPhase: 1.037004 
    Freq:50000.00 RzMag: 99.958923 Ohm , RzPhase: 1.010885 
    Freq:50000.00 RzMag: 99.948708 Ohm , RzPhase: 1.033138 
    Freq:50000.00 RzMag: 99.958923 Ohm , RzPhase: 1.010885 
    Freq:50000.00 RzMag: 99.958923 Ohm , RzPhase: 1.010885 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.960312 Ohm , RzPhase: 1.015318 
    Freq:50000.00 RzMag: 99.949104 Ohm , RzPhase: 1.039497 
    Freq:50000.00 RzMag: 99.956947 Ohm , RzPhase: 1.014751 
    Freq:50000.00 RzMag: 99.947716 Ohm , RzPhase: 1.035071 
    Freq:50000.00 RzMag: 99.948708 Ohm , RzPhase: 1.033138 
    Freq:50000.00 RzMag: 99.959908 Ohm , RzPhase: 1.008959 
    Freq:50000.00 RzMag: 99.957932 Ohm , RzPhase: 1.012818 
    Freq:50000.00 RzMag: 99.955948 Ohm , RzPhase: 1.016677 
    Freq:50000.00 RzMag: 99.993782 Ohm , RzPhase: 1.024464 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.958923 Ohm , RzPhase: 1.010885 
    Freq:50000.00 RzMag: 99.958923 Ohm , RzPhase: 1.010885 
    Freq:50000.00 RzMag: 99.946342 Ohm , RzPhase: 1.030645 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.958923 Ohm , RzPhase: 1.010885 
    Freq:50000.00 RzMag: 99.956947 Ohm , RzPhase: 1.014751 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 

Reply
  • Hi,

    Apologies for the typo.

    Infact, Waitclks must be scaled as below:

    AD5940_Delay10us(WaitClks/100); 

    instead of 

    AD5940_Delay10us(WaitClks);

    1) Since in the above code, wakeup timer is not used, measurement is not periodically triggered, Measure() need to be called for each measurement, hence called inside AppBIAISR().

    2) ADC must be turned on only for sampling the input. It should not be kept on always. Otherwise data fifo will be filled with junk data.

      In the above code, WG is kept on always.

    3) Floating switches after measurement is a good practice but optional. It is not reflected in the waveform captured above because switches are closed for a negligibly small duration.

    4) Toggling the GPIO_Pin2 helps check that measurement is happening and also to keep count of measurements, by monitoring GPIO2.

    5) Measure() is not using sequence in the above code as measurement is not required to be triggered by timer and sequence can run only at 32kHz clock.

    Hence its sequence is already removed in the above code.

    Below is the BIA measurement output I got for the above code for a 100 Ohm resistive load:

    Hello AD5940-Build Time:11:10:34
    Freq:50000.00 RzMag: 99.953804 Ohm , RzPhase: 1.029252 
    Freq:50000.00 RzMag: 99.953979 Ohm , RzPhase: 1.020536 
    Freq:50000.00 RzMag: 99.954971 Ohm , RzPhase: 1.018610 
    Freq:50000.00 RzMag: 99.958328 Ohm , RzPhase: 1.019177 
    Freq:50000.00 RzMag: 99.960709 Ohm , RzPhase: 1.021670 
    Freq:50000.00 RzMag: 99.958328 Ohm , RzPhase: 1.019177 
    Freq:50000.00 RzMag: 99.951485 Ohm , RzPhase: 1.041997 
    Freq:50000.00 RzMag: 99.960312 Ohm , RzPhase: 1.015318 
    Freq:50000.00 RzMag: 99.961296 Ohm , RzPhase: 1.013385 
    Freq:50000.00 RzMag: 99.960312 Ohm , RzPhase: 1.015318 
    Freq:50000.00 RzMag: 99.958328 Ohm , RzPhase: 1.019177 
    Freq:50000.00 RzMag: 99.958328 Ohm , RzPhase: 1.019177 
    Freq:50000.00 RzMag: 99.960709 Ohm , RzPhase: 1.021670 
    Freq:50000.00 RzMag: 99.952477 Ohm , RzPhase: 1.040064 
    Freq:50000.00 RzMag: 99.956947 Ohm , RzPhase: 1.014751 
    Freq:50000.00 RzMag: 99.961296 Ohm , RzPhase: 1.013385 
    Freq:50000.00 RzMag: 99.957932 Ohm , RzPhase: 1.012818 
    Freq:50000.00 RzMag: 99.955948 Ohm , RzPhase: 1.016677 
    Freq:50000.00 RzMag: 99.956947 Ohm , RzPhase: 1.014751 
    Freq:50000.00 RzMag: 99.956947 Ohm , RzPhase: 1.014751 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.957932 Ohm , RzPhase: 1.012818 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.947716 Ohm , RzPhase: 1.035071 
    Freq:50000.00 RzMag: 99.957932 Ohm , RzPhase: 1.012818 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.956947 Ohm , RzPhase: 1.014751 
    Freq:50000.00 RzMag: 99.946732 Ohm , RzPhase: 1.037004 
    Freq:50000.00 RzMag: 99.958923 Ohm , RzPhase: 1.010885 
    Freq:50000.00 RzMag: 99.948708 Ohm , RzPhase: 1.033138 
    Freq:50000.00 RzMag: 99.958923 Ohm , RzPhase: 1.010885 
    Freq:50000.00 RzMag: 99.958923 Ohm , RzPhase: 1.010885 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.960312 Ohm , RzPhase: 1.015318 
    Freq:50000.00 RzMag: 99.949104 Ohm , RzPhase: 1.039497 
    Freq:50000.00 RzMag: 99.956947 Ohm , RzPhase: 1.014751 
    Freq:50000.00 RzMag: 99.947716 Ohm , RzPhase: 1.035071 
    Freq:50000.00 RzMag: 99.948708 Ohm , RzPhase: 1.033138 
    Freq:50000.00 RzMag: 99.959908 Ohm , RzPhase: 1.008959 
    Freq:50000.00 RzMag: 99.957932 Ohm , RzPhase: 1.012818 
    Freq:50000.00 RzMag: 99.955948 Ohm , RzPhase: 1.016677 
    Freq:50000.00 RzMag: 99.993782 Ohm , RzPhase: 1.024464 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.958923 Ohm , RzPhase: 1.010885 
    Freq:50000.00 RzMag: 99.958923 Ohm , RzPhase: 1.010885 
    Freq:50000.00 RzMag: 99.946342 Ohm , RzPhase: 1.030645 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 
    Freq:50000.00 RzMag: 99.958923 Ohm , RzPhase: 1.010885 
    Freq:50000.00 RzMag: 99.956947 Ohm , RzPhase: 1.014751 
    Freq:50000.00 RzMag: 99.959312 Ohm , RzPhase: 1.017244 

Children
  • Thanks, the code provided does work.

    I have removed the floating switch part, so the sine wave is continuous as checked on an oscilloscope.

    So, this is what I am trying to do now:

    I'm injecting the continuous sine wave generated between CEO and Ain1, and measuring the voltage across part of the body (forearm) between Ain2 and 3. This part works.

    I'm trying to measure the heart rate, and as you can see it is sort of working, but not quite yet

    I want to understand, does some TIA or input current or anything else is trying to stabilize or auto-calibrate periodically? The impedance values shift i.e. either increases or decreases over time as if trying to stabilize or something. Do you know why it could be happening? 

    PS: In the figure above, don't look at the values but look at the pattern i.e. the the pattern is slanting downwards to the right from left means impedance values are decreasing over time for a fixed electrode position on the body.

  • Hi,

    If the requirement is to measure heart rate, may I know why you are not using the AD5940_ECG example?

    May I know if you are testing using eval board or on your custom board?

    If using Eval-AD5940BIOZ board with ECG probes stuck on bodyAD5940_ECG example gives below measurement output:

    Note: Eval board uses AD8233 (heart rate monitor) along with AD5940.

  • Hmm, good point, I'll probably look into it, I used AD8421 as my IA, but I will check it out, thanks! 

    So coming back to the slanting issue mentioned above, could you think of anything why it could be happening?

    Also, I do appreciate your help in this matter!

    Edit: I think the methodology to measure the HRM via AD8233 vs the way I'm doing is different. I'm amplitude modulating the pulse signal vs the conventional way AD8233 acquires the ECG signal. Quick question, when AD8233 is operational, is AD594x injecting current in the body?

  • Also, whats the max Bia ODR? I can see it's 20 currently.

  • BIA ODR can go upto 3kHz. However, in Sensorpal, it is limited to 20.

  • Hi,

    No. AD594x doesn't inject any current.

  • Hi Akila,

    Could you please tell me where should I make changes in the code above to get an ODR of 3k Hz? I changed the BIAODR to 3k, but it didn't work.

    Shravan

  • Hi,

    Kindly watch the value of MAXODR for different configurations, so that you may choose the config with maximum MAXODR.

    (MAXODR is defined in the default BIA example in Github)

  • MAXODR

    So I checked the code and it says:

     AppBIACfg.MaxODR = 1/(((AppBIACfg.MeasSeqCycleCount + 10) / 16.0)* 1E-6)  ;

    I guess this is what you mean? 

    The other comment is "DFT number and sample frequency decides the maxim ODR", I changed the DFT number to DFTNUM_16384 and it didn't do anything. Also, my DAC freq is below 80kHz.

  • Hi,

    Yes.  AppBIACfg.MaxODR = 1/(((AppBIACfg.MeasSeqCycleCount + 10) / 16.0)* 1E-6)  ;