hoverboard-firmware-hack-serial-esc/Src/control.c

#include "stm32f1xx_hal.h"
#include "defines.h"
#include "setup.h"
#include "config.h"

TIM_HandleTypeDef TimHandle;
uint16_t ppm_captured_value[PPM_NUM_CHANNELS+1] = {0};
uint8_t ppm_count = 0;
uint32_t timeout = 100;

void PPM_ISR_Callback() {
  // Dummy loop with 16 bit count wrap around
  uint16_t rc_delay = TIM2->CNT;
  TIM2->CNT = 0;

  if (rc_delay > 3000) {
    ppm_count = 0;
  }
  else if (ppm_count < PPM_NUM_CHANNELS){
    timeout = 0;
    ppm_captured_value[ppm_count] = CLAMP(rc_delay, 1000, 2000) - 1000;
    ppm_count++;
  }

}

void PPM_Init() {
  GPIO_InitTypeDef GPIO_InitStruct;
  /*Configure GPIO pin : PA3 */
  GPIO_InitStruct.Pin = GPIO_PIN_3;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_FALLING;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
  GPIO_InitStruct.Pull = GPIO_PULLDOWN;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  __HAL_RCC_TIM2_CLK_ENABLE();
  TimHandle.Instance = TIM2;
  TimHandle.Init.Period = UINT16_MAX;
  TimHandle.Init.Prescaler = (SystemCoreClock/DELAY_TIM_FREQUENCY_US)-1;;
  TimHandle.Init.ClockDivision = 0;
  TimHandle.Init.CounterMode = TIM_COUNTERMODE_UP;
  HAL_TIM_Base_Init(&TimHandle);

  /* EXTI interrupt init*/
  HAL_NVIC_SetPriority(EXTI3_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(EXTI3_IRQn);
  HAL_TIM_Base_Start(&TimHandle);
}