#include "define.h" //адреса и значения регистров (не пользуюсь cmsis, hal)

volatile int up;
volatile int down;

void main(void){
  RCC_AHB1ENR |= RCC_AHB1ENR_GPIOA; //GPIOA clocking
  RCC_APB1ENR |= RCC_APB1ENR_TIM2; //TIM2 clocking

  GPIOA_MODER |= GPIOA_MODER_AF_P0; //GPIOA0 alternate function
  GPIOA_AFRL |= GPIOA_AFRL_AF1_P0 //GPIOA0 TIM2_CH1

  TIM2_PSC = 16-1; //Prescaler 16
  
  TIM2_CCMR1 |= TIM2_CCMR1_CC1S_0_1; //Select TI1 active input for TIM2_CCR1
  TIM2_CCER &= ~TIM2_CCER_CC1P &
               ~TIM2_CCER_CC1NP; //TI1FP1 rising edge

  TIM2_CCMR1 |= TIM2_CCMR1_CC2S_1_0; //Select TI1 active input for TIM2_CCR2
  TIM2_CCER |= TIM2_CCER_CC2P &
              ~TIM2_CCER_CC2NP; //TI1FP2 falling edge
  
  TIM2_SMCR |= TIM2_SMCR_TS_1_0_1; //Select TI1FP1 valid trigger input
  TIM2_SMCR |= TIM2_SMCR_SMS_1_0_0; //Reset mode
  
  TIM2_CCER |= TIM2_CCER_CC1E; //Enable the capture CC1            
  TIM2_CCER |= TIM2_CCER_CC2E; //Enable the capture CC2
  
  TIM2_DIER |= TIM2_DIER_CC1IE; //Enable the interrupt CC1
  TIM2_DIER |= TIM2_DIER_CC2IE; //Enable the interrupt CC2

  TIM2_CR1 |= TIM2_CR1_CEN; //Counter enabled
  
  NVIC_ISER0 |= NVIC_ISER0_TIM2; //TIM2 Interrupt
  
  while(1);
}

//обработчик прерывания (startup.c)
void interrupt(void){
        if(TIM2_SR & 2) up=TIM2_CCR1;
        if(TIM2_SR & 4) down=TIM2_CCR2;
        TIM2_SR = 0;
}

void interrupt(void)
{
     uint32_t Flags = TIM2_SR;
     TIM2_SR = ~Flags;

     if(Flags & TIM_SR_CC1IF)
        up=TIM2_CCR1;
     if(Flags & TIM_SR_CC2IF)
        down=TIM2_CCR2;
}

TIM2_DIER |= 0
    | TIM2_DIER_CC1IE    //Enable the interrupt CC1
    | TIM2_DIER_CC2IE    //Enable the interrupt CC2
  ;

NVIC_ISER0 |= NVIC_ISER0_TIM2; //TIM2 Interrupt

typedef STM32::TIM::Timer<STM32::TIM::TIM_3>        tmr;

void Init ()
{
    tmr::EnableClocks ();

// вход - PC7, TIM3_CH2

// частота таймера - 10 кГц
    tmr::TIMx->PSC = CLOCK_APB1_TIM / 10000- 1;
    tmr::TIMx->ARR = 0xFFFF;

    tmr::TIMx->CR1 = TIM_CR1_CKD_1;                            // предделитель на 4 для фильтров

    tmr::Ch2::CCMRx =    tmr::Ch1::CCMR_CCS_IC1_CROSS |        // первый канал - на второй вход
                        tmr::Ch2::CCMR_CCS_IC1 |            // второй канал - туда же
                        tmr::Ch1::CCMR_CCS_FILTER * 15 |    // фильтр - восемь сэмплов на 1/32-й частоты
                        tmr::Ch2::CCMR_CCS_FILTER * 15;        // убирает импульсы короче 57 мкс

    tmr::TIMx->CCER =    tmr::Ch1::CCER_CCxE |                // включаем оба канала
                        tmr::Ch2::CCER_CCxE |
                        tmr::Ch2::CCER_CCxP;                // второй канал - по заднему фронту

    tmr::TIMx->SMCR =    TIM_SMCR_TS_0 * 6 |                    // trigger input - filtered timer input 2
                        TIM_SMCR_SMS_0 * 4;                    // slave mode - reset mode

// прерывание по сбросу таймера
    tmr::UpdateInterrupt::Enable ();
    NVIC_EnableIRQ (tmr_irq);

    tmr::Enable();

}


void IrqProcess ()
{
    tmr::UpdateInterrupt::Clear ();


    int32_t cur_period = tmr::TIMx->CCR2;
    int32_t on_time = tmr::TIMx->CCR1;

    int32_t off_time = cur_period - on_time;

    // тут был кусочек пред-обработки

    // перезапускаем таймер - импульсы идут
    stop_tmr.Restart ();
}

  TIM2_CCER |= TIM2_CCER_CC2P &
              ~TIM2_CCER_CC2NP; //TI1FP2 falling edge

TIM2_CCER |= TIM2_CCER_CC2P &
              ~TIM2_CCER_CC2NP; //TI1FP2 falling edge

TIM2_CCER |= TIM2_CCER_CC2P;

TIM2_CCER = 0
    | 0 * TIM2_CCER_CC4NP   // 0 - single edge, 1 - both edges
    | 0 * TIM2_CCER_CC4P    // 0 - rising edge, 1 - falling edge/both edges
    | 0 * TIM2_CCER_CC4E    // 0 - disabled, 1 - enabled
    | 0 * TIM2_CCER_CC3NP
    | 0 * TIM2_CCER_CC3P
    | 0 * TIM2_CCER_CC3E
    | 0 * TIM2_CCER_CC2NP
    | 1 * TIM2_CCER_CC2P
    | 1 * TIM2_CCER_CC2E
    | 0 * TIM2_CCER_CC1NP
    | 0 * TIM2_CCER_CC1P
    | 0 * TIM2_CCER_CC1E
;