STM32F pulse packet

#include "stm32f4_discovery.h"

/**************************************************************************************/

void RCC_Configuration(void)

{

  /* --------------------------- System Clocks Configuration -----------------*/

  /* TIM1 clock enable */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);

  /* TIM3 clock enable */

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

  /* GPIOA clock enable */

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

}

/**************************************************************************************/

void GPIO_Configuration(void)

{

  GPIO_InitTypeDef GPIO_InitStructure;

  /*-------------------------- GPIO Configuration ----------------------------*/

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Connect TIM1 pins to AF */

  GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_TIM1);

}

/**************************************************************************************/

void TIM1_Configuration(void)

{

  TIM_OCInitTypeDef  TIM_OCInitStructure;

  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

  uint16_t Period;

  Period = 1000000 / 20000; // 20 KHz from 1MHz prescaled

  /* Time base configuration */

  TIM_TimeBaseStructure.TIM_Prescaler = (SystemCoreClock / 1000000) - 1; // Get clock to 1 MHz on STM32F2/F4

  TIM_TimeBaseStructure.TIM_Period = Period - 1;

  TIM_TimeBaseStructure.TIM_ClockDivision = 0;

  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseStructure.TIM_RepetitionCounter = 5 - 1; // Five Pulses per trigger

  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

  /* Enable TIM1 Preload register on ARR */

  TIM_ARRPreloadConfig(TIM1, ENABLE);

  /* TIM PWM1 Mode configuration */

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;

  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

  TIM_OCInitStructure.TIM_Pulse = Period / 2; // 50%

  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

  /* Output Compare PWM1 Mode configuration: Channel1 PA.08 */

  TIM_OC1Init(TIM1, &TIM_OCInitStructure);

  TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable);

  /* One Pulse Mode selection */

  TIM_SelectOnePulseMode(TIM1, TIM_OPMode_Single);

  /* Input Trigger selection */

  TIM_SelectInputTrigger(TIM1, TIM_TS_ITR2); // Slave TIM1, Trigger TIM3 (TS=2)

  /* Slave Mode selection: Trigger Mode */

  TIM_SelectSlaveMode(TIM1, TIM_SlaveMode_Trigger);

  /* TIM1 Main Output Enable */

  TIM_CtrlPWMOutputs(TIM1, ENABLE);

  /* TIM1 enable counter */

  TIM_Cmd(TIM1, ENABLE);

}

/**************************************************************************************/

void TIM3_Configuration(void)

{

  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

  uint16_t Period;

  Period = 1000000 / 50; // 50 Hz from 1MHz prescaled

  /* Time base configuration */

  TIM_TimeBaseStructure.TIM_Prescaler = ((SystemCoreClock / 2) / 1000000) - 1; // Get clock to 1 MHz on STM32F2/F4

  TIM_TimeBaseStructure.TIM_Period = Period - 1;

  TIM_TimeBaseStructure.TIM_ClockDivision = 0;

  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

  /* Trigger of TIM3 Update into TIM1 Slave */

  TIM_SelectOutputTrigger(TIM3, TIM_TRGOSource_Update);

  /* TIM3 enable counter */

  TIM_Cmd(TIM3, ENABLE);

}

/**************************************************************************************/

int main(void)

{

  RCC_Configuration();

  GPIO_Configuration();

  TIM1_Configuration();

  TIM3_Configuration();

  while(1); // Don't want to exit

}

 /* Enable the TIM8 gloabal Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = TIM8_UP_TIM13_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
 /* TIM Interrupts enable */
  TIM_ITConfig(TIM8, TIM_IT_Update , ENABLE);

................

//Interrupt Handler
void   TIM8_UP_TIM13_IRQHandler(void)
{
  if (TIM_GetITStatus(TIM8, TIM_IT_Update) != RESET)
  {
    TIM_ClearITPendingBit(TIM8, TIM_IT_Update);

    tim8_counter--;
    if ( tim8_counter != 0)
    {
         TIM8_Restart();
    }
  }
}