Maxim Integrated's IoT development kit
Dependencies: MAX30101 MAX30003 MAX113XX_Pixi MAX30205 max32630fthr USBDevice
max30101_algo.cpp
- Committer:
- mahirozturk
- Date:
- 2018-05-09
- Revision:
- 12:1300cb0f6274
- Parent:
- 1:efe9cad8942f
- Child:
- 13:fba77a5d0fa0
File content as of revision 12:1300cb0f6274:
/******************************************************************************* * Copyright (C) 2018 Maxim Integrated Products, Inc., All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. * * Except as contained in this notice, the name of Maxim Integrated * Products, Inc. shall not be used except as stated in the Maxim Integrated * Products, Inc. Branding Policy. * * The mere transfer of this software does not imply any licenses * of trade secrets, proprietary technology, copyrights, patents, * trademarks, maskwork rights, or any other form of intellectual * property whatsoever. Maxim Integrated Products, Inc. retains all * ownership rights. ******************************************************************************* */ #include "max30101_algo.h" //helper functions for the heart rate and SpO2 function uint16_t avg_dc_est(int32_t *p, uint16_t x); void lp_dfir_flt(int16_t din0, int16_t din1, int16_t din2, int16_t *dout0, int16_t *dout1, int16_t *dout2) ; int32_t mul16(int16_t x, int16_t y); // // Heart Rate/SpO2 Monitor function takes sample input 'dinIR' and dinRed. // Other inputs: // ns -> Sample Counter, increments with each sample input. // SampRate -> Input data real-time sample rate. // dinLShft -> Number of left shifts for data to be 16 bit wide. // compSpO2 -> If '1' compute SpO2 value,else compute HR only. // // Outputs: // ir_ac_comp -> AC component of the IR signal. // red_ac_comp -> AC component of the Red signal. // ir_ac_mag -> Peak to Peak magnitude of the IR signal. // red_ac_mag -> Peak to Peak magnitude of the Red signal. // HRbpm -> Heart Rate in beats per minute. // SpO2 -> SpO2 value as %saturation. // DRdy -> '1' when new data is available. // void HRSpO2Func(uint32_t dinIR, uint32_t dinRed, uint32_t dinGreen, uint32_t ns, uint16_t SampRate, uint16_t compSpO2, int16_t *ir_ac_comp, int16_t *red_ac_comp, int16_t *green_ac_comp, int16_t *ir_ac_mag, int16_t *red_ac_mag, int16_t *green_ac_mag, uint16_t *HRbpm2, uint16_t *SpO2B, uint16_t *DRdy) { static int32_t ir_avg_reg = 0; static int32_t red_avg_reg = 0; static int32_t green_avg_reg = 0; static int16_t ir_ac_sig_cur = 0; static int16_t ir_ac_sig_min = 0; static int16_t ir_ac_sig_max = 0; static int16_t ir_avg_est; static int16_t ir_pedge = 0, ir_nedge = 0; static int16_t ir_pzxic, ir_pzxip; static int16_t ir_nzxic; static int16_t red_ac_sig_cur = 0; static int16_t red_ac_sig_min = 0; static int16_t red_ac_sig_max = 0; static int16_t red_avg_est; static int16_t green_avg_est; static int16_t green_ac_sig_cur = 0; //static int16_t green_ac_sig_cur=0; static int16_t green_ac_sig_pre; static int16_t green_ac_sig_max ; static int16_t green_ac_sig_min; static int16_t green_mac_FIFO[5]; int16_t meanGreenMagFIFO; int16_t minAmpForHeartBeat ; uint32_t IRData, RedData, greenData, rnum, rden, rdens; uint16_t zeros_in_HrQue = 0, posCount = 0; static uint32_t prevPeakLoc = 0; static int16_t IrFIFO[100]; static int16_t HrQue[10], lastKnownGoodHr[10]; static int16_t SPO2Que[5]; int16_t SPO2score[5]; static uint16_t HrQindex = 0, lengthOfposCountExceeding = 0; static uint16_t initHrQueCounter = 0, fingerOff = 0; static int16_t HrQueSmoothing[3]; static int16_t SPO2QueSmoothing[3]; int16_t k, j; uint32_t peakLoc ; int16_t bufferIdx1, bufferIdx2; int16_t maxFIFO, IdxMaxFIFO ; int16_t HRperiod2, HRComp2, deltaHR; int16_t cSpO2, SpO2; int16_t HrCount = 0, HrSum = 0, meanGreenMagFIFOcounter = 0; int16_t SPO2D, meanHrQ; int16_t dx[99], cumsumX[99]; static int16_t SPO2QueCounter = 0 ; //, lastDisplayedHrValue; int16_t validSPO2Count = 0; int16_t validSPO2Sum = 0; int16_t SPO2scoreAverage = 0; int16_t SPO2scoreSum = 0 ; // int16_t deltaMeanLastKnownGoodHr = 0, meanLastKnownGoodHr = 0; // int16_t counterMeanLastKnownGoodHr = 0; /* clear some vars if fresh new start */ if ((ns == 0) || (fingerOff > 300)) { ir_avg_reg = 0; red_avg_reg = 0; green_avg_reg = 0; ir_ac_sig_cur = 0; ir_ac_sig_min = 0; ir_ac_sig_max = 0; ir_avg_est = 0; green_avg_est = 0; red_avg_est = 0 ; ir_pedge = 0; ir_nedge = 0; ir_pzxic = 0; ir_pzxip = 0; ir_nzxic = 0 ; //ir_nzxip = 0; red_ac_sig_cur = 0; red_ac_sig_min = 0; red_ac_sig_max = 0; prevPeakLoc = 0 ; bufferIdx1 = 0 ; bufferIdx2 = 0; HrQindex = 0; initHrQueCounter = 0; lengthOfposCountExceeding = 0 ; fingerOff = 0; HRComp2 = 0; for (k = 0 ; k < 100 ; k++) { IrFIFO[k] = 0; } for (k = 0 ; k < 10 ; k++) { HrQue[k] = 0; lastKnownGoodHr[k] = 0; } for (k = 0 ; k < 3 ; k++) { HrQueSmoothing[k] = 70; SPO2QueSmoothing[k] = 97; } for (k = 0 ; k < 5 ; k++) { SPO2Que[k] = 97; SPO2score[k] = 0; green_mac_FIFO[k] = 0; } SPO2QueCounter = 0; *SpO2B = 97; *HRbpm2 = 0; *DRdy = 0 ; } /* Save current state */ green_ac_sig_pre = green_ac_sig_cur; /* Process next data sample */ minAmpForHeartBeat = 0; IRData = dinIR; RedData = dinRed; greenData = dinGreen ; ir_avg_est = avg_dc_est(&ir_avg_reg, IRData); red_avg_est = avg_dc_est(&red_avg_reg, RedData); green_avg_est = avg_dc_est(&green_avg_reg, greenData); lp_dfir_flt((uint16_t)(IRData - ir_avg_est), (uint16_t)(RedData - red_avg_est), (uint16_t)(greenData - green_avg_est), &ir_ac_sig_cur, &red_ac_sig_cur, &green_ac_sig_cur); *ir_ac_comp = ir_ac_sig_cur; *red_ac_comp = red_ac_sig_cur; *green_ac_comp = green_ac_sig_cur; /* save to FIFO */ for (k = 1 ; k < 100 ; k++) { IrFIFO[100 - k] = IrFIFO[99 - k]; } IrFIFO[0] = green_ac_sig_cur ; // invert for (k = 0 ; k < 97 ; k++) { dx[k] = IrFIFO[k + 2] - IrFIFO[k] ; } dx[97] = dx[96]; dx[98] = dx[96]; for (k = 0 ; k < 99 ; k++) { if (dx[k] > 0) { dx[k] = 1; } else { dx[k] = 0; } } cumsumX[0] = 0; for (k = 1; k < 99 ; k++) { if (dx[k] > 0) { cumsumX[k] = cumsumX[k - 1] + dx[k] ; } else { cumsumX[k] = 0; } } /* determine noise * ignore less than 3 consecutive non-zeros's * detect # of sign change */ posCount = 0; for (k = 1; k < 99 ; k++) { if (cumsumX[k] > 0) { posCount ++ ; } else if (cumsumX[k] == 0) { if (posCount < 4 && k >= 4) { for (j = k - 1; j > k - posCount - 1; j--) { cumsumX[j] = 0 ; } } posCount = 0; } } /* ignore less than 3 consecutive zeros's */ posCount = 0; for (k = 1; k < 99 ; k++) { if (cumsumX[k] == 0) { posCount ++ ; } else if (cumsumX[k] > 0) { if (posCount < 4 && k >= 4) { for (j = k - 1; j > k - posCount - 1; j--) { cumsumX[j] = 100 ; } } posCount = 0; } } /* detect # of sign change */ posCount = 0; /* sign change counter */ for (k = 0; k < 98 ; k++) { if (cumsumX[k] == 0 && cumsumX[k + 1] > 0) { posCount ++; } } if (posCount >= 4) { lengthOfposCountExceeding ++ ; } else { lengthOfposCountExceeding = 0 ; } /* Detect IR channel positive zero crossing (rising edge) */ if ((green_ac_sig_pre < 0) && (green_ac_sig_cur >= 0) && fingerOff == 0) { *ir_ac_mag = ir_ac_sig_max - ir_ac_sig_min; *red_ac_mag = red_ac_sig_max - red_ac_sig_min; *green_ac_mag = green_ac_sig_max - green_ac_sig_min; if (*green_ac_mag > 0) { for (k = 0; k < 4 ; k++) { green_mac_FIFO[k] = green_mac_FIFO[k + 1]; } green_mac_FIFO[4] = *green_ac_mag ; if (green_mac_FIFO[4] > 1000) { green_mac_FIFO[4] = 1000; } } meanGreenMagFIFO = 0; meanGreenMagFIFOcounter = 0; for (k = 0; k < 5 ; k++) { if (green_mac_FIFO[k] > 0) { meanGreenMagFIFO = meanGreenMagFIFO + green_mac_FIFO[k] ; meanGreenMagFIFOcounter++; } } if (meanGreenMagFIFOcounter >= 2) { meanGreenMagFIFO = meanGreenMagFIFO / meanGreenMagFIFOcounter ; minAmpForHeartBeat = meanGreenMagFIFO / 4 ; //25% of mean of past heart beat } else { minAmpForHeartBeat = 75; } if (minAmpForHeartBeat < 75) { minAmpForHeartBeat = 75; } if (minAmpForHeartBeat > 400) { minAmpForHeartBeat = 400; } ir_pedge = 1; ir_nedge = 0; ir_ac_sig_max = 0; ir_pzxip = ir_pzxic; ir_pzxic = ns; bufferIdx1 = ir_pzxic - ir_nzxic; bufferIdx2 = ir_pzxic - ir_pzxip; if ((*green_ac_mag) > minAmpForHeartBeat && (*green_ac_mag) < 20000 && bufferIdx1 >= 0 && bufferIdx1 < 100 && bufferIdx2 >= 0 && bufferIdx2 < 100 && bufferIdx1 < bufferIdx2) { // was <5000 maxFIFO = -32766; IdxMaxFIFO = 0; for (j = bufferIdx1; j <= bufferIdx2; j++) { // find max peak if (IrFIFO[j] > maxFIFO) { maxFIFO = IrFIFO[j]; IdxMaxFIFO = j; } } peakLoc = ir_pzxic - IdxMaxFIFO + 1 ; if (prevPeakLoc != 0) { HRperiod2 = (uint16_t)(peakLoc - prevPeakLoc); if (HRperiod2 > 33 && HRperiod2 < 134) { HRComp2 = (6000 / HRperiod2); fingerOff = 0 ; } else { HRComp2 = 0 ; } } else { HRComp2 = 0 ; } if (initHrQueCounter < 10 && HRComp2 > 0) { HrQue[HrQindex] = HRComp2; HrQindex++; initHrQueCounter ++; if (HrQindex == 10) { HrQindex = 0; } } if (initHrQueCounter > 7 && lengthOfposCountExceeding <= 3) { if (HRComp2 > 0) { HrCount = 0; HrSum = 0; zeros_in_HrQue = 0; for (k = 1 ; k < initHrQueCounter ; k++) { if (HrQue[k] > 0) { HrSum += HrQue[k]; HrCount ++; } else { zeros_in_HrQue ++; } } meanHrQ = HrSum / HrCount ; deltaHR = lastKnownGoodHr[0] / 10; if (HRComp2 > lastKnownGoodHr[0] - deltaHR && HRComp2 < lastKnownGoodHr[0] + deltaHR) { for (k = 1 ; k < 10 ; k++) { HrQue[10 - k] = HrQue[9 - k]; } HrQue[0] = HRComp2; } /* HR smoothing using FIFO queue */ if (zeros_in_HrQue <= 2) { for (k = 1 ; k < 3 ; k++) { HrQueSmoothing[3 - k] = HrQueSmoothing[2 - k]; } HrQueSmoothing[0] = meanHrQ ; HRComp2 = ((HrQueSmoothing[0] << 2) + (HrQueSmoothing[1] << 1) + (HrQueSmoothing[2] << 1)) >> 3; *HRbpm2 = HRComp2 ; for (k = 1 ; k < 10 ; k++) { lastKnownGoodHr[10 - k] = lastKnownGoodHr[9 - k]; } lastKnownGoodHr[0] = HRComp2; } } } else if (initHrQueCounter < 7) { /* before que is filled up, display whatever it got. */ *HRbpm2 = HRComp2; } else { // *HRbpm2 = 0 ; HrCount = 0; HrSum = 0; for (k = 0 ; k < 10 ; k++) { if (lastKnownGoodHr[k] > 0) { HrSum = HrSum + lastKnownGoodHr[k]; HrCount++; } } if (HrCount > 0) { *HRbpm2 = HrSum / HrCount; } else { *HRbpm2 = 0; } } prevPeakLoc = peakLoc ; /* save peakLoc into Static var */ if (compSpO2) { rnum = (ir_avg_reg >> 20) * (*red_ac_mag); rden = (red_avg_reg >> 20) * (*ir_ac_mag); rdens = (rden >> 15); if (rdens > 0) { cSpO2 = 110 - (((25 * rnum) / (rdens)) >> 15); } if (cSpO2 >= 100) { SpO2 = 100; } else if (cSpO2 <= 70) { SpO2 = 70; } else { SpO2 = cSpO2; } SPO2Que[SPO2QueCounter ] = SpO2; for (k = 0 ; k < 5 ; k++) { SPO2score[k] = 0; for (j = 0 ; j < 5 ; j++) if (abs(SPO2Que[k] - SPO2Que[j]) > 5) { SPO2score[k] ++; } } SPO2scoreSum = 0; for (k = 0 ; k < 5 ; k++) { SPO2scoreSum += SPO2score[k] ; } SPO2scoreAverage = SPO2scoreSum / 5; for (k = 1 ; k < 5 ; k++) { SPO2score[k] = SPO2score[k] - SPO2scoreAverage; } validSPO2Count = 0; validSPO2Sum = 0; for (k = 1 ; k < 5 ; k++) { if (SPO2score[k] <= 0) { // add for HR to report validSPO2Sum += SPO2Que[k]; validSPO2Count ++; } } if (validSPO2Count > 0) { SPO2D = (validSPO2Sum / validSPO2Count) - 1; } if (SPO2D > 100) { SPO2D = 100; } SPO2QueCounter ++; if (SPO2QueCounter == 5) { SPO2QueCounter = 0; } for (k = 1 ; k < 3 ; k++) { SPO2QueSmoothing[3 - k] = SPO2QueSmoothing[2 - k]; } SPO2QueSmoothing[0] = SPO2D; *SpO2B = ((SPO2QueSmoothing[0] << 2) + (SPO2QueSmoothing[1] << 1) + (SPO2QueSmoothing[2] << 1)) >> 3; if (*SpO2B > 100) { *SpO2B = 100 ; } } else { SpO2 = 0; *SpO2B = 0; } *DRdy = 1; } } /* Detect IR channel negative zero crossing (falling edge) */ if ((green_ac_sig_pre > 0) && (green_ac_sig_cur <= 0)) { ir_pedge = 0; ir_nedge = 1; ir_ac_sig_min = 0; ir_nzxic = ns; } /* Find Maximum IR & Red values in positive cycle */ if (ir_pedge && (green_ac_sig_cur > green_ac_sig_pre)) { ir_ac_sig_max = ir_ac_sig_cur; red_ac_sig_max = red_ac_sig_cur; green_ac_sig_max = green_ac_sig_cur; } /* Find minimum IR & Red values in negative cycle */ if (ir_nedge && (green_ac_sig_cur < green_ac_sig_pre)) { ir_ac_sig_min = ir_ac_sig_cur; red_ac_sig_min = red_ac_sig_cur; green_ac_sig_min = green_ac_sig_cur; } if (IRData < 50000) { // finger-off fingerOff++; *DRdy = 0; } else { fingerOff = 0 ; } if (*SpO2B == 0 || *HRbpm2 == 0) { *DRdy = 0; } } /* * Average DC Estimator */ uint16_t avg_dc_est(int32_t *p, uint16_t x) { *p += ((((int32_t) x << 15) - *p) >> 4); return (*p >> 15); } /* * Symmetric Dual Low Pass FIR Filter */ void lp_dfir_flt(int16_t din0, int16_t din1, int16_t din2, int16_t *dout0, int16_t *dout1, int16_t *dout2) { static const uint16_t FIRCoeffs[12] = {688, 1283, 2316, 3709, 5439, 7431, 9561, 11666, 13563, 15074, 16047, 16384 }; static int16_t cbuf0[32], cbuf1[32], cbuf2[32]; static int16_t offset = 0; int32_t y0, y1, y2; int16_t i; cbuf0[offset] = din0; cbuf1[offset] = din1; cbuf2[offset] = din2; y0 = mul16(FIRCoeffs[11], cbuf0[(offset - 11) & 0x1F]); y1 = mul16(FIRCoeffs[11], cbuf1[(offset - 11) & 0x1F]); y2 = mul16(FIRCoeffs[11], cbuf2[(offset - 11) & 0x1F]); for (i = 0; i < 11; i++) { y0 += mul16(FIRCoeffs[i], cbuf0[(offset - i) & 0x1F] + cbuf0[(offset - 22 + i) & 0x1F]); y1 += mul16(FIRCoeffs[i], cbuf1[(offset - i) & 0x1F] + cbuf1[(offset - 22 + i) & 0x1F]); y2 += mul16(FIRCoeffs[i], cbuf2[(offset - i) & 0x1F] + cbuf2[(offset - 22 + i) & 0x1F]); } offset = (offset + 1) & 0x1F; *dout0 = (y0 >> 15); *dout1 = (y1 >> 15); *dout2 = (y2 >> 15); } /* * Integer multiplier */ int32_t mul16(int16_t x, int16_t y) { return (int32_t)(x * y); }