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STM32 Discovery, RC Receiver, PWM Input

Question asked by chia.benjamin on Feb 21, 2014
/* Includes ------------------------------------------------------------------*/
#include "stm32f4xx.h"
#include "stm32f4xx_syscfg.h"
#include "stm32f4xx_rcc.h"
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_exti.h"
#include "misc.h"
 
/** @addtogroup STM32F4_Discovery_Peripheral_Examples
  * @{
  */
 
/** @addtogroup EXTI
  * @{
  */
 
/* Private typedef -----------------------------------------------------------*/
 
EXTI_InitTypeDef   EXTI_InitStructure;
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
void EXTILine0_Config(void);
void LEDInit(void);
int ch10;
/* Private functions ---------------------------------------------------------*/
 
/**
  * @brief  EXTI Example program
  * @param  None
  * @retval None
  */
 
int initdelete3(void){
      /* Initialize LED4 mounted on STM32F4-Discovery board */
      LEDInit();
 
      /* Configure EXTI Line0 (connected to PA0 pin) in interrupt mode */
      EXTILine0_Config();
 
      return 0;
}
void delete3(void)
{
 
  /* Generate software interrupt: simulate a rising edge applied on EXTI0 line */
  //EXTI_GenerateSWInterrupt(EXTI_Line0);
 
  //while (1)
    __NOP();
}
 
/**
  * @brief  Configures LED GPIO.
  * @param  None
  * @retval None
  */
void LEDInit()
{
  GPIO_InitTypeDef  GPIO_InitStructure;
 
  /* Enable the GPIO_LED Clock */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
 
  /* Configure the GPIO_LED pin */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOD, &GPIO_InitStructure);
}
 
/**
  * @brief  Configures EXTI Line0 (connected to PA0 pin) in interrupt mode
  * @param  None
  * @retval None
  */
void EXTILine0_Config(void)
{
 
  GPIO_InitTypeDef   GPIO_InitStructure;
  NVIC_InitTypeDef   NVIC_InitStructure;
  TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
 
  /* Enable GPIOA clock */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
  /* Enable SYSCFG clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
 
  /* TIM5 clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5, ENABLE);
 
  /* Time base configuration - SystemCoreClock = 168000000 for 168 MHz board ABP1 @ 42 MHz (DIV4) */
   TIM_TimeBaseStructure.TIM_Prescaler =(uint16_t) (((SystemCoreClock / 1000000) / 2) - 1); // Shooting for 1 MHz, (1us)
   TIM_TimeBaseStructure.TIM_Period = 10000 - 1;        ////0xFFFF; // Maximal
   TIM_TimeBaseStructure.TIM_ClockDivision = 0;
   TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
   TIM_TimeBaseInit(TIM5, &TIM_TimeBaseStructure);
 
  /* TIM enable counter */
   TIM_Cmd(TIM5, ENABLE);
 
  /* Configure PA0 pin as input floating */
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
 
  /* Connect EXTI Line0 to PA0 pin */
  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);
 
  /* Configure EXTI Line0 */
  EXTI_InitStructure.EXTI_Line = EXTI_Line0;
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising_Falling;
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure);
 
  /* Enable and set EXTI Line0 Interrupt to the lowest priority */
  NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x01;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}
 
/**
  * @brief  This function handles External line 0 interrupt request.
  * @param  None
  * @retval None
  */
void EXTI0_IRQHandler(void)
{
  if(EXTI_GetITStatus(EXTI_Line0) != RESET)
  {
    /* Toggle LED1 */
    GPIO_ToggleBits(GPIOD, GPIO_Pin_13);
    ch10 = TIM_GetCounter(TIM5);
 
 
    /* Clear the EXTI line 0 pending bit */
    EXTI_ClearITPendingBit(EXTI_Line0);
  }
}

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