#include "stm32f4xx.h" // Device header
#include "Handlers.h"
#include "LCDHD44780NonBlocking.h"
#include "BloodPressureMeterFunctions.h"
#include "PressureSensorABPMANN005PG2A3.h"
#include "FIRbandpass_3_10_Hz_Coeff.h"
#include "FIRfilterPtByPt.h"
#include "IIRfilterPtByPt.h"
/*=================================
Formula for pressure calculation:
pressure = ((Output - 1638) * 5)/(14745 - 1638)
1 psi = 51.7149326 mmHg
3.480619445 psi = 180 mmHg
10762 = 180 mmHg
//================================*/
//=== Instances of structures and pointers to structures ===//
pulseWave_ _pulseWave;
pulseWave_* pulseWave = &_pulseWave;
FIRfilterObject _BandpassFIRfilter;
FIRfilterObject* BandpassFIRfilter = &_BandpassFIRfilter;
IIR4thOrderFilterObj _LowpassIIRfilter;
IIR4thOrderFilterObj* LowpassIIRfilter = &_LowpassIIRfilter;
//=== Extern variables enabling calculations and display ===//
extern volatile uint8_t calculate;
extern volatile uint8_t displayOnLCDevery1sec;
extern volatile uint8_t displayOnLCDevery250milisec;
//=========== FIR filter coefficients ===========//
extern float FIRbandpass_3_10_Hz_Coeff[166];
//==== Circular buffers to pass into FIRfilterObject ===//
float signalBufferForBandpassFIRfilter[256];
int main()
{
RCCClockConfiguration();
/* FPU initialization */
SCB->CPACR |= ((3UL << 10*2)|(3UL << 11*2)); /* set CP10 and CP11 Full Access */
PumpValveButtonConfiguration();
LCDInitialize();
TimersInitialization();
LCDLocateXY(0,0);
LCDSendText("Put cuff on arm ");
LCDLocateXY(0,1);
LCDSendText("press button ");
PressureSensorInitialize();
//====== Initialization of pointers ======//
float LPFiltered;
float BPFiltered;
float* lowPassFiltered;
float* bandPassFiltered;
lowPassFiltered = &LPFiltered;
bandPassFiltered = &BPFiltered;
//==============================//
volatile float previousValue, derivative, previousDerivative; // Variables for determining change of 1st derivative sign of lowpass filtered output
volatile float previousValueBP, derivativeBP, previousDerivativeBP; // Variables for determining change of 1st derivative sign of bandpass filtered output
_BandpassFIRfilter = CreateFIRfilterObject(256, signalBufferForBandpassFIRfilter, 166, FIRbandpass_3_10_Hz_Coeff);
_LowpassIIRfilter = IIR_4thOrderSignalFilteringPtByPtInitialize(IIRforwardCoeffLowpass_20Hz, IIRreverseCoeffLowpass_20Hz);
unsigned int BPfilterDelay = (unsigned int) (_BandpassFIRfilter.coefficientsLength - 1) / 2; // Length of bandpass FIR filter group delay
volatile uint8_t displayHeart = 0; // Variable controlling display of heart character on LCD
volatile uint8_t clearHeart = 0; // Variable controlling clear of heart character on LCD
volatile uint8_t calculateMAP = 0; // Variable controlling start of MAP evaluation
while(1)
{
if(calculate)
{
if( pressureArrayHead != pressureArrayTail)
{
//======================= Filtration of data from pressure sensor ========================//
IIR_4thOrderSignalFilteringPtByPt(LowpassIIRfilter, pressureArray[pressureArrayTail], lowPassFiltered);
FIRfilterPtByPt(BandpassFIRfilter, pressureArray[pressureArrayTail], bandPassFiltered);
//======================= Update of buffers and variables values ========================//
pulseWave->currentPressure = ((*lowPassFiltered- 1638.0f) * 5.0f) / (14745.0f - 1638.0f) * 52.0f;
pulseWave->numberOfSamples++;
Last128SamplesBufferHead = (Last128SamplesBufferHead+1) & 127;
Last128SamplesBuffer[Last128SamplesBufferHead] = *lowPassFiltered;
pressureArrayTail = (pressureArrayTail + 1) & pressureArrayMask;
//======= New derivative value calculation =======//
derivative = *lowPassFiltered - previousValue;
derivativeBP = *bandPassFiltered - previousValueBP;
//====================== Peak detection ======================//
if( ((derivative * previousDerivative) < 0) && ((derivative - previousDerivative) < 0) )
{
if((pulseWave->numberOfSamples - pulseWave->previousPeakXcoordinate ) > 64) // if two Peaks distance > approximate 250 ms
{
displayHeart = 1;
pulseWave->previousPeakXcoordinate = pulseWave->numberOfSamples;
}
if( ! pulseWave->systolicPressure )
{
calculateMAP = 1; // if Systolic peak detected start evaluating MAP
pulseWave->systolicPressure = pulseWave->currentPressure;
}
}
//======================== MAP calculation =========================//
if( calculateMAP )
{
if( ((derivativeBP * previousDerivativeBP) < 0) && ((derivativeBP - previousDerivativeBP) < 0) )
{
if( *bandPassFiltered > pulseWave->workingMAPpressure )
{
pulseWave->MAPpressure = ((Last128SamplesBuffer[(Last128SamplesBufferHead - BPfilterDelay) & 127] - 1638.0f) * 5.0f) / (14745.0f - 1638.0f) * 52.0f;
pulseWave->workingMAPpressure = *bandPassFiltered;
}
}
}
//============ Variables update =============//
previousDerivative = derivative;
previousValue = *lowPassFiltered;
previousDerivativeBP = derivativeBP;
previousValueBP = *bandPassFiltered;
//============ Ending calculations ==============//
if( pulseWave->currentPressure < 50 )
{
LCDLocateXY(0,0);
LCDSendText("SYS:");
LCDLocateXY(7,0);
LCDSendData(' ');
LCDLocateXY(8,0);
LCDSendText("DIA:");
calculate = 0;
calculateMAP = 0;
TIM4->CR1 &= ~TIM_CR1_CEN; // Turn off Timer controlling displaying on LCD
displayOnLCDevery1sec = 0;
displayOnLCDevery250milisec = 0;
pulseWave->diastolicPressure = ( pulseWave->MAPpressure * 3 - pulseWave->systolicPressure ) / 2 ;
LCDLocateXY(4,0);
LCDSend8bitInteger((uint8_t) pulseWave->systolicPressure);
LCDLocateXY(12,0);
LCDSend8bitInteger((uint8_t) pulseWave->diastolicPressure);
LCDLocateXY(0,1);
LCDSendText("MAP: ");
LCDLocateXY(6,1);
LCDSend8bitInteger((uint8_t) pulseWave->MAPpressure);
LCDLocateXY(12,1);
LCDSendText(" ");
}
}
}
else
{
if( pressureArrayHead != pressureArrayTail)
{
//======================= Filtration of data from pressure sensor ========================//
IIR_4thOrderSignalFilteringPtByPt(LowpassIIRfilter, pressureArray[pressureArrayTail], lowPassFiltered);
FIRfilterPtByPt(BandpassFIRfilter, pressureArray[pressureArrayTail], bandPassFiltered);
//======================= Update of buffers and variables values ========================//
Last128SamplesBufferHead = (Last128SamplesBufferHead+1) & 127;
Last128SamplesBuffer[Last128SamplesBufferHead] = *lowPassFiltered;
pressureArrayTail = (pressureArrayTail + 1) & pressureArrayMask;
pulseWave->currentPressure = ((*lowPassFiltered- 1638.0f) * 5.0f) / (14745.0f - 1638.0f) * 52.0f;
previousDerivative = *lowPassFiltered - previousValue;
previousDerivativeBP = *bandPassFiltered - previousValueBP;
previousValue = *lowPassFiltered;
previousValueBP = *bandPassFiltered;
}
}
if(displayOnLCDevery250milisec)
{
if(clearHeart)
{
LCDLocateXY(8,0);
LCDSendData(' ');
clearHeart = 0;
}
if(displayHeart)
{
LCDLocateXY(8,0);
LCDSendData(heart);
displayHeart = 0;
clearHeart = 1;
}
displayOnLCDevery250milisec = 0;
}
if(displayOnLCDevery1sec)
{
LCDLocateXY(12,1);
LCDSend8bitInteger((uint8_t) pulseWave->currentPressure);
displayOnLCDevery1sec = 0;
}
}
}
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