/*
 * 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 COUNT_FROM_RPM(RPM) ((1E6/(MICROSECS_PULSE * 30 / (RPM ) )))


uint16_t nominal = 0;
uint16_t halfRot;
uint16_t phase10 = 100; // 10 degrees
volatile uint16_t sampleRefCount = 0;
volatile uint16_t  sampleVar;
volatile uint16_t sampleRef;


int gainControl = 1000 ;

volatile uint8_t haveSlowPulse = 0;

uint16_t rpm;
signed count;
signed delta;

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


    // link TIM3 ITR2 to TIM2 reload
    // use TS = 001 to make TRC from Tim2 TRIGGER
	TIM3->SMCR  &= ~(TIM_SMCR_TS_Msk );
	TIM3->SMCR  |=  TIM_SMCR_TS_0; // select ITR2 as trigger source TRC

    TIM3->CCMR1 |=  TIM_CCMR1_CC2S_1 |  TIM_CCMR1_CC2S_0 ; //  The CC2S bits are 11, use TRC

	TIM3->CCER = TIM_CCER_CC1E | TIM_CCER_CC2E;

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


    nvicEnableVector(TIM3_IRQn,
                          4);



    TIM3->DIER |= TIM_DIER_CC1IE  | TIM_DIER_CC2IE;
}


void recalcPhase(void)
{
	nominal = halfRot * (long) (phase10)/ 1800;
}

void adjustRPM(void)
{
	if(rpm < 600)
		rpm = 600;
	if(rpm >  5000)
		rpm = 5000;

}

uint16_t setRPM(uint16_t rpm_ )
{
	if(rpm_ >= 600 && rpm_ < 6000)
	{
	  rpm = rpm_;
	  adjustRPM();
	}
	  return halfRot;
}

uint16_t getRPM(void)
{
	return rpm;
}

signed getDelta(void)
{
	return delta;
}

signed getCount(void)
{
	return  count;
}

void setGain(int gain)
{
	gainControl = gain;
}


uint8_t slowPulse(void)
{
	return haveSlowPulse;
}


void processPhase (int refCount,int varCount, int diff)
{

    // scale it up by 32
	// at this point we should try to phase lock


	signed pd = 0;
	bool lock = false;
// basically locked
	if(refCount==1 && varCount==1 )
	{
		lock = true;
       pd = (diff <  32768 ? diff : diff - 65536L) ;
	}
	// frequency detector
	else if (refCount > 1)
	{
		pd = (refCount*32768L);
	}
	else if (varCount > 1)
	{
		pd = (-varCount * 32768L);
	}
    float delta_phi = pd/ (gainControl * 1.0);


    delta = pd;



    // phase detector returns +/



    float const wn = 0.01;
    float const zeta = 0.707f; // was 0.707
    float const K = 1000;

    float const t1 = K/(wn*wn);
    float const t2 = 2 * zeta/wn;
    float const  b0 = (4*K/t1)*(1.+t2/2.0f);
    float const b1 = (8*K / t1);
    float const b2 = (4*K/t1)*(1.-t2/2.0f);

    float const a1 = -2.0f;
    float const a2 = 1.0f;
    static float v0=0, v1 = 0, v2 = 0 ;


    static float phi_hat = 100.0f;


    v2=v1; v1=v0;
    v0 = delta_phi -v1 *a1 -v2 *a2;


    phi_hat = v0 * b0 + v1 * b1 + v2 * b2 ;



    // 6.283 = 1.0 Hz

    // 62.2 = 10Hz
    // decide on whether to go for forcing loop or to track

    int32_t arr;

   // 	if(lock)


       arr = (6283000L/MICROSECS_PULSE)/ (phi_hat+60);

    if(arr > 20000)
    	arr = 20000;
    if(arr < 100)
    	arr = 100;



     count = arr;

    TIM2->ARR = arr ;
    recalcPhase();



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

	rpm =  nomRPM ;


	adjustRPM();
    }




// set the timing advance from reference to
void setAdvance(int16_t deg10)
{
    phase10 = deg10;
    recalcPhase();

}

// timer 3 interrupt
void VectorB4(void)
{
    static uint16_t lastSampleRef = 0;
    static uint8_t refCount = 0;
	static uint8_t varCount = 0;
	uint16_t samplePeriod;

	uint16_t stat = TIM3->SR;
	if(stat & TIM_SR_CC1IF)
	{
		TIM3->SR &= ~TIM_SR_CC1IF;
		uint16_t sample = TIM3->CCR1;
		if(sample-lastSampleRef >  100 /*BREAKER_COUNT_MIN */)
		{
			sampleRef = sample;

			++refCount;
		}
     	samplePeriod = sample-lastSampleRef;

     	chDbgCheck(samplePeriod != 65535);
     	lastSampleRef = sample;
	}
	if(stat & TIM_SR_CC2IF)
	{
		TIM3->SR &= ~TIM_SR_CC2IF;
		 sampleVar  = TIM3->CCR2;
		 ++varCount;
	}




    if(refCount != 0 && varCount != 0  ) /*we have an R,V pair  */
    {

//
    processPhase (refCount,varCount,sampleRef-sampleVar);
    haveSlowPulse = (varCount > 20);
   refCount = 0;
   varCount = 0;
   }



}