File content as of revision 12:9d30df1529be:

//////////////////////
// Operation Modes  //
//////////////////////

/////////////////
// Variables:  //
/////////////////

// Filter mode - Regular /  efficient
//#define EFFICIENT_FILTER

// second-order sections filter variables - upto 8 sections
#define MAX_SECTION_NUMBER 5

// convertions
#define ADC2Float (2.0f/4095.0f) // 0.0004884f//
#define Float2ADC (4095.0f/2.0f) // 2047.5f   //

// Filter variables
//SOS Matrix limited to order 10
int   FilterSections=1;
float SOSMat[5][6]= { // Predefined SOS Matrix (second order 5Khz filter
    1, -2, 1,  1, -1.961,  0.9624,
    0,  0, 0,  0,  0,  0,
    0,  0, 0,  0,  0,  0,
    0,  0, 0,  0,  0,  0,
    0,  0, 0,  0,  0,  0
};
float Gscale = 0.9810f;
float filterCurrInput[MAX_SECTION_NUMBER+1] = {0};
float filterLastInput[MAX_SECTION_NUMBER+1] = {0};
float filterLLastInput[MAX_SECTION_NUMBER+1] = {0};

// Trigger mode variables
float signalGain = 1.0; // Signal Gain
float trigTresh = 0.5; // threshold for trigger mode
uint32_t trigDelaySet = 5000; // counter for pulse pass
uint32_t trigDelay = trigDelaySet; // counter for pulse pass
uint32_t trigPause = 10; // pause after trigger in microseconds

// Buffer mode variables - Mid work
uint32_t bufferSizeSet = 5000;
uint32_t bufferSize = bufferSizeSet;
uint32_t preBufferSizeSet = 1000;
uint32_t bufferCountDown = bufferSizeSet - preBufferSizeSet;
float bufferADC[5000] = {0};

// gains vector
#define GAIN_VECTOR_SIZE 5
int gainsVectorSize = 5;
float GainVector[] = {0.1 , 0.2 , 0.4 , 0.8 , 1.6};

///////////////////////////////
//    available filters:     //
///////////////////////////////
// off mode, output vdd/2
inline void offMode(void);
// passthrough function (output equals input)
inline void passthrough(void);
// highpass filter
inline void highpass(void);
// highpass filter + trigger mode
inline void highpassTrig(void);
// highpass filter + trigger mode + Gains vector
inline void GainsTrig(void);
// highpass filter + trigger mode + Delays vector
inline void DelaysTrig(void);
// highpass filter + trigger mode + FIR Filter (Convolution)
inline void FIRTrig(void);
// filter_implementation
inline float HPF_Function(float ADCFloat);

//////////////////////////////
//    Filter Function:      //
//////////////////////////////
// filter_implementation
inline float HPF_Function(float ADCFloat)
{
    // filter local variable
    float ADCFloatFiltered;
    // filter mode:
#ifdef EFFICIENT_FILTER
    // filter coeficients best performance if defined in loop
    float SOSMatHP[2][6] = { // 25khz cutoff at 920 kHz sample rate // closer to 30kHz when io toggle switched off.
        1.000000,  -2.000000,  1.000000,  1.000000,  -1.706510,  0.731145,
        1.000000,  -2.000000,  1.000000,  1.000000,  -1.852377,  0.879117
    };
    float GscaleHP = 0.801724;
    // num sections
    int NumSectionsHP = sizeof(SOSMatHP)/sizeof(float)/6;
    // filter stages variables
    static float CurrInput [MAX_SECTION_NUMBER+1];
    static float LastInput [MAX_SECTION_NUMBER+1];
    static float LLastInput [MAX_SECTION_NUMBER+1];

    //////////////////
    // Apply Filter //
    //////////////////
    LLastInput[0] = LastInput[0];
    LastInput[0] = CurrInput[0];
    CurrInput[0] = ADCFloat;
    for (int ii=1; ii <= NumSectionsHP; ii++) {
        LLastInput[ii] = LastInput[ii];
        LastInput[ii] = CurrInput[ii];
        CurrInput[ii] = SOSMatHP[ii-1][0]*CurrInput[ii-1] + SOSMatHP[ii-1][1]*LastInput[ii-1] +
                        SOSMatHP[ii-1][2]*LLastInput[ii-1] -
                        SOSMatHP[ii-1][4]*LastInput[ii] - SOSMatHP[ii-1][5]*LLastInput[ii];
        ADCFloatFiltered = CurrInput[ii];
    }

    ADCFloatFiltered = ADCFloatFiltered * GscaleHP * signalGain;

#else
    filterLLastInput[0] = filterLastInput[0];
    filterLastInput[0] = filterCurrInput[0];
    filterCurrInput[0] = ADCFloat;
    for (int ii=1; ii <= FilterSections; ii++) {
        filterLLastInput[ii] = filterLastInput[ii];
        filterLastInput[ii] = filterCurrInput[ii];
        filterCurrInput[ii] = SOSMat[ii-1][0]*filterCurrInput[ii-1] + SOSMat[ii-1][1]*filterLastInput[ii-1] +
                              SOSMat[ii-1][2]*filterLLastInput[ii-1] -
                              SOSMat[ii-1][4]*filterLastInput[ii] - SOSMat[ii-1][5]*filterLLastInput[ii];

    }
    ADCFloatFiltered = filterCurrInput[FilterSections];
    ADCFloatFiltered = ADCFloatFiltered * Gscale * signalGain;
#endif
    return ADCFloatFiltered;
}


///////////////////////////////
//   Operation Functions:    //
///////////////////////////////
// off mode, output vdd/2
inline void offMode(void)
{
    // generate some delay (limit loop speeds, creates crashes to the Switch mcu
//    for (int ii=0; ii<10; ii++){
//        __ASM volatile ("nop");    // one tick operation, Use to adjust frequency by slowing down the proccess
//    }
    uint16_t ADCValueOut;
    // set to vdd/2
    ADCValueOut=(uint16_t)((0.0f +1.0f) * Float2ADC);
    // Output value using DAC
    *(__IO uint32_t *) Dac_Reg  = ADCValueOut;
}// end off mode

// passthrough function (output equals input)
inline void passthrough(void)
{
    uint32_t ADCValue;

    // Read ADC input
    ADCValue = hadc1.Instance->DR;
    // Output value using DAC
    *(__IO uint32_t *) Dac_Reg  = ADCValue;

} // end passthrough


// high pass filter
inline void highpass(void)
{
    // Dac output variable
    uint16_t ADCValueOut;

    // Read ADC input
    float ADCFloat=((uint16_t)(hadc1.Instance->DR) * ADC2Float)-1.0f;

    // Apply Filter
    float ADCFloatFiltered = HPF_Function( ADCFloat );

    // Apply Saturation to Output
    if (ADCFloatFiltered < -1.0f) {
        ADCValueOut=0; // Min value
    } else if (ADCFloatFiltered > 1.0f) {
        ADCValueOut=0xFFF; // Max value
    } else {
        ADCValueOut=(uint16_t)((ADCFloatFiltered +1.0f) * Float2ADC);
    }

    // Output value using DAC
    // HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_1, DAC_ALIGN_12B_R, ADCValueOut);
    *(__IO uint32_t *) Dac_Reg = ADCValueOut;

} // end high pass filter

// highpass filter + trigger mode
inline void highpassTrig(void)
{
    // trigger variables
    static bool trigFlag=0; // flag to indicate trigger event

    // Dac output variable
    uint16_t ADCValueOut;

    // Read ADC input
    float ADCFloat=((uint16_t)(hadc1.Instance->DR) * ADC2Float)-1.0f;

    // Apply Filter
    float ADCFloatFiltered = HPF_Function( ADCFloat );

    ///////////////////////////////////////////////
    // Event detection                           //
    ///////////////////////////////////////////////
    if (trigFlag) { // event already detected
        trigDelay--;
        if (trigDelay == 0) { // pulse pass run out, perform delay and reset variables
            trigDelay = trigDelaySet; //reset counter for next iteration
            trigFlag=0;
            // reset filter
            ADCFloatFiltered = 0;
            // update dac
            ADCValueOut=(uint16_t)((ADCFloatFiltered +1.0f) * Float2ADC);
            *(__IO uint32_t *) Dac_Reg = ADCValueOut;
            //*(__IO uint32_t *) Dac_Reg = 0; // test triggered mode
            // delay for set time
            wait_ms(trigPause);
        }
    } else if (ADCFloatFiltered >= trigTresh) {
        trigFlag=1;
    }
    ////////////////////////////////
    // Apply Saturation to Output //
    ////////////////////////////////

    if (ADCFloatFiltered < -1.0f) {
        ADCValueOut=0; // Min value
    } else if (ADCFloatFiltered > 1.0f) {
        ADCValueOut=0xFFF; // Max value
    } else {
        ADCValueOut=(uint16_t)((ADCFloatFiltered +1.0f) * Float2ADC);
    }

    // Output value using DAC
    // HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_1, DAC_ALIGN_12B_R, ADCValueOut);
    *(__IO uint32_t *) Dac_Reg = ADCValueOut;
    //wait_us(1);
} // end high pass filter + trigger mode


// highpass filter + trigger mode + Gains vector
inline void GainsTrig(void)
{
    // Gains variables:
    static int GainVectorIndex = 0;
    // trigger variables
    static bool trigFlag=0; // flag to indicate trigger event
    // Dac output variable
    uint16_t ADCValueOut;

    // Read ADC input
    float ADCFloat=((uint16_t)(hadc1.Instance->DR) * ADC2Float)-1.0f;

    // Apply Filter
    float ADCFloatFiltered = HPF_Function( ADCFloat );


    ///////////////////////////////////////////////
    // Event detection                           //
    ///////////////////////////////////////////////
    if (trigFlag) { // event already detected
        trigDelay--;
        if (trigDelay == 0) { // pulse pass run out, perform delay and reset variables
            trigDelay = trigDelaySet; //reset counter for next iteration
            trigFlag=0;
            // reset filter
            ADCFloatFiltered = 0;
            // update dac
            ADCValueOut=(uint16_t)((ADCFloatFiltered +1.0f) * Float2ADC);
            *(__IO uint32_t *) Dac_Reg = ADCValueOut;
            //*(__IO uint32_t *) Dac_Reg = 0; // test triggered mode
            // delay for set time
            wait_ms(trigPause);

            // change gain settings
            GainVectorIndex++;
            GainVectorIndex = GainVectorIndex % gainsVectorSize;
        }
    } else if (ADCFloatFiltered >= trigTresh) {
        trigFlag=1;
    }
    //////////////////////////
    // Apply Gain to Output //
    //////////////////////////
    ADCFloatFiltered = ADCFloatFiltered * GainVector[GainVectorIndex];

    if (ADCFloatFiltered < -1.0f) {
        ADCValueOut=0; // Min value
    } else if (ADCFloatFiltered > 1.0f) {
        ADCValueOut=0xFFF; // Max value
    } else {
        ADCValueOut=(uint16_t)((ADCFloatFiltered +1.0f) * Float2ADC);
    }

    // Output value using DAC
    // HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_1, DAC_ALIGN_12B_R, ADCValueOut);
    *(__IO uint32_t *) Dac_Reg = ADCValueOut;
    //wait_us(1);
} // end GainsTrig





//////////////////////////////////////////////
/////////////////// Implement
//////////////////////////////////////////////

// highpass filter + trigger mode + Delays vector
inline void DelaysTrig(void)  // - mid work feature. (not working yet)
{
    ///////////////////////////////
    //    Gains variables:       //
    ///////////////////////////////
#define DELAY_VECTOR_SIZE 5
    uint32_t DelayVector[] = {100 , 200 , 300 , 400 , 500}; // millis
    static uint16_t DelayVectorIndex = 0;
    static uint32_t BufferIndex = 0;

//uint32_t bufferSizeSet = 5000;
//uint32_t preBufferSizeSet = 1000;
//uint32_t bufferCountDown = bufferSizeSet - preBufferSizeSet;
//float bufferADC[bufferSizeSet] = {0};
    ///////////////////////////////
    //    filter variables:      //
    ///////////////////////////////
    // filter coeficients best performance if defined in loop
    float SOSMatHP[2][6] = { // 25khz cutoff at 920 kHz sample rate // closer to 30kHz when io toggle switched off.
        1.000000,  -2.000000,  1.000000,  1.000000,  -1.706510,  0.731145,
        1.000000,  -2.000000,  1.000000,  1.000000,  -1.852377,  0.879117
    };
    float GscaleHP = 0.801724;

    // num sections
    int NumSectionsHP = sizeof(SOSMatHP)/sizeof(float)/6;

    float ADCFloat;
    float ADCFloatFiltered;
    uint16_t ADCValueOut;

    // filter stages variables
    static float CurrInput [MAX_SECTION_NUMBER+1];
    static float LastInput [MAX_SECTION_NUMBER+1];
    static float LLastInput [MAX_SECTION_NUMBER+1];

    // trigger variables
    static bool trigFlag=0; // flag to indicate trigger event

    ////////////////////
    // Read ADC input //
    ////////////////////
    ADCFloat=((uint16_t)(hadc1.Instance->DR) * ADC2Float)-1.0f;

    //////////////////////////////////////////////////////
    // Apply Filter to input                            //
    //////////////////////////////////////////////////////

    LLastInput[0] = LastInput[0];
    LastInput[0] = CurrInput[0];
    CurrInput[0] = ADCFloat;
    for (int ii=1; ii <= NumSectionsHP; ii++) {
        LLastInput[ii] = LastInput[ii];
        LastInput[ii] = CurrInput[ii];
        CurrInput[ii] = SOSMatHP[ii-1][0]*CurrInput[ii-1] + SOSMatHP[ii-1][1]*LastInput[ii-1] +
                        SOSMatHP[ii-1][2]*LLastInput[ii-1] -
                        SOSMatHP[ii-1][4]*LastInput[ii] - SOSMatHP[ii-1][5]*LLastInput[ii];
        ADCFloatFiltered = CurrInput[ii];
    }

    ADCFloatFiltered = ADCFloatFiltered * GscaleHP;

    ////////////////////////////////
    // Fill in buffer             //
    ////////////////////////////////
    bufferADC[BufferIndex] = ADCFloatFiltered;
    BufferIndex++;
    BufferIndex = BufferIndex % bufferSize;
    ///////////////////////////////////////////////
    // Event detection                           //
    ///////////////////////////////////////////////
    if (trigFlag) { // event already detected
        bufferCountDown--; // count down
        if (bufferCountDown == 0) { // pulse pass run out, perform delay and reset variables
            bufferCountDown = bufferSizeSet - preBufferSizeSet; //reset counter for next iteration
            trigFlag=0;
            // reset filter
            for (int ii=1; ii <= NumSectionsHP; ii++) {
                LLastInput[ii] = 0;
                LastInput[ii] = 0;
                CurrInput[ii] = 0;
                ADCFloatFiltered = 0;
            }

            // generate delay
            // delay for set time
            wait_ms(DelayVector[DelayVectorIndex]);
            // change delay settings
            DelayVectorIndex++;
            DelayVectorIndex = DelayVectorIndex % DELAY_VECTOR_SIZE;


            // play out buffer
            for (int ii=0 ; ii<bufferSize ; ii++) {

                ADCFloatFiltered = bufferADC[BufferIndex];
                BufferIndex++;
                BufferIndex = BufferIndex % bufferSize;
                ////////////////////////////////
                // Apply Saturation to Output //
                ////////////////////////////////

                if (ADCFloatFiltered < -1.0f) {
                    ADCValueOut=0; // Min value
                } else if (ADCFloatFiltered > 1.0f) {
                    ADCValueOut=0xFFF; // Max value
                } else {
                    ADCValueOut=(uint16_t)((ADCFloatFiltered +1.0f) * Float2ADC);
                }

                // Output value using DAC
                // HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_1, DAC_ALIGN_12B_R, ADCValueOut);
                *(__IO uint32_t *) Dac_Reg = ADCValueOut;
                //wait_us(1);
            }
        }
    } else if (ADCFloatFiltered >= trigTresh) {
        trigFlag=1;
    }

} // end GainsTrig