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/*

 * timer2.c

 *

 *  Created on: 2 Apr 2018

 *      Author: Mike

 */

#include "ch.h"  // needs for all ChibiOS programs

#include "hal.h" // hardware abstraction layer header

#include "timer2.h"

#define  MICROSECS_PULSE 10

// with a dwell angle of 45 degrees , 4 cylinders and a maximum RPM of 5000

// freq = 5000/60 * 2 = 166Hz. Because the breaker might bounce , we accept the

// first pulse longer than 1/300 of a second as being a proper closure .

// the TIM2 counter counts in 10uS increments,

#define BREAKER_COUNT_MIN (1E6/(MICROSECS_PULSE * 300))

#define SAMPLE_BUFF_SIZE 256

uint16_t halfRot;

uint16_t nominal  = 0;

uint16_t phase10 = 100; // 10 degrees

volatile uint16_t sampleCount = 0;

uint16_t outSampleCount = 0;

volatile uint16_t sampleBuff[SAMPLE_BUFF_SIZE];

typedef enum { WAIT_GAP, SKIP_BOUNCE, HAVE_SAMPLE } sampleState_t ;

sampleState_t  sampleState = WAIT_GAP;

// difference between samples

volatile uint16_t deltaTime;

uint16_t rpm;

void initTimer2()

{

        rccEnableTIM2(FALSE);

        rccResetTIM2();

        TIM2->PSC = 72*MICROSECS_PULSE;

        TIM2->ARR = 60000;

        TIM2->CR1 = ~TIM_CR1_CKD  & (TIM_CR1_CEN |

                        TIM_CR1_ARPE );

        /// pulse width 200 uS

        TIM2->CCR1 = 200/MICROSECS_PULSE;

    TIM2->CCER =  TIM_CCER_CC1E | TIM_CCER_CC1P  ; //enabled and active high

    TIM2->CCMR1 = TIM_CCMR1_OC1M_0 | TIM_CCMR1_OC1M_1 | TIM_CCMR1_OC1M_2 |

                           TIM_CCMR1_OC1PE ;

    TIM2->CR2 = TIM_CR2_MMS_1 ; // trigger out is 010 = update

    // change the TIM2 CC2 to TIM3 CC1

        rccEnableTIM3(FALSE);

        rccResetTIM3();

        // TIM3 on the PA6 ... pins : remap code 00

        AFIO->MAPR &= ~ AFIO_MAPR_TIM3_REMAP;

        TIM3->PSC = 72*MICROSECS_PULSE;

        TIM3->ARR = 0xFFFF;

        TIM3->CCMR1 = TIM_CCMR1_CC1S_0 /* | TIM_CCMR1_IC1F_0 | TIM_CCMR1_IC1F_1 | TIM_CCMR1_IC1F_2 */ ;  // filter 16, input

        TIM3->CCER = TIM_CCER_CC1E;

    // link TIM3 ITR1 to TIM2 reload

    // use CCR3

    TIM3->CCMR2 = TIM_CCMR2_CC3S_1 | TIM_CCMR2_CC3S_0 ; //  The

        TIM3->CR1 = ~TIM_CR1_CKD  & (TIM_CR1_CEN | TIM_CR1_ARPE );

    nvicEnableVector(TIM3_IRQn,

                          4);

    TIM3->DIER |= TIM_DIER_CC1IE ;

}

void recalcPhase(void)

{

        nominal = halfRot * (long) (phase10)/ 1800;

}

void adjustRPM(void)

{

        if(rpm < 600)

                rpm = 600;

        if(rpm >  5000)

                rpm = 5000;

        float pulseSec = rpm /30;

halfRot = 1e6 / (pulseSec * MICROSECS_PULSE) ;

  TIM2->ARR = halfRot;

recalcPhase();

}

uint16_t setRPM(uint16_t rpm_ )

{

        if(rpm_ >= 600 && rpm_ < 5000)

        {

          rpm = rpm_;

          adjustRPM();

        }

          return halfRot;

}

uint16_t getRPM(void)

{

        return rpm;

}

uint16_t getDelta(void)

{

        return deltaTime;

}

uint16_t wrapIndex(uint16_t index)

{

        if (index >= SAMPLE_BUFF_SIZE)

                index -= SAMPLE_BUFF_SIZE;

    return index;

}

// allows for wrapping

uint16_t getSampleBuff(uint16_t index)

{

        chSysLock();

        return sampleBuff[wrapIndex(index)];

        chSysUnlock();

}

// waits for ignition pulse , debounces readings,

// returns the pulse time, skips debounce time

uint16_t getNextPulse(void)

{

        static uint16_t lastSampleIndex = 0;

        while(1)

        {

                        while (outSampleCount == sampleCount)

                                chThdSleep(10);

                        uint16_t thisTime  = getSampleBuff(outSampleCount);

                        outSampleCount = wrapIndex(outSampleCount + 1);

                        while (outSampleCount == sampleCount)

                                chThdSleep(10);

                        uint16_t nextTime = getSampleBuff(outSampleCount);

                        // calculate wrapped time delta : should be > than bounce time to allow

                        uint16_t diffTime = nextTime - thisTime;

                        if(diffTime > BREAKER_COUNT_MIN)

                        {

                                lastSampleIndex = outSampleCount;

                                return nextTime;

                        }

        }

  return 0;

}

void processNextPulse(uint16_t retVal)

{

        static uint16_t lastVal = 0;

        // at this point we should try to phase lock

    deltaTime = retVal - lastVal;

    if(deltaTime > 10000)

    {

        __asm(" BKPT #0");

    }

    lastVal = retVal;

    float nomRPM = 30E6 / (MICROSECS_PULSE * deltaTime) ;

        rpm = rpm + (nomRPM -rpm)/10;

        uint16_t skew = 32768 - nominal;

        long delta = (retVal+skew) - (nominal+skew);

        if(delta > 10)

                rpm = rpm - 1;

        if(delta -10)

                rpm = rpm + 1;

//      rpm += delta / 256;

        adjustRPM();

    }

// set the timing advance from reference to

void setAdvance(int16_t deg10)

{

    phase10 = deg10;

    recalcPhase();

}

// timer 3 interrupt

void VectorB4(void)

{

        uint16_t stat = TIM3->SR;

        if(stat & TIM_SR_CC1IF)

        {

                TIM3->SR &= ~TIM_SR_CC1IF;

            uint16_t sample = TIM3->CCR1;

            sampleBuff[sampleCount++] = sample;

            if (sampleCount >= SAMPLE_BUFF_SIZE)

                sampleCount = 0;

        }

}