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STM32F4 PWM genertation using TIM1 and TIM8

Question asked by gandalf on Apr 15, 2012
Latest reply on Apr 15, 2012 by Clive One
I am using the STM32F4 discovery board to generate a PWM signal using TIMER 1, channel 1, and am using GPIO A8 in AF mode. When i run the code there is no pulse generated, but the pin A8 gets pulled up to Vcc.

 The above mentioned happens for TIMER 8 too(Channel 1, GPIO PC6). I did not have any problem configuring the other Timer's. Since i intend to use the repetition counter i have to work with Timer 1 and Timer 8. I would really appreciate it if someone could help me out here.

The code i attached below:




#include "stm32f4_discovery.h"

TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
uint16_t CCR1_Val = 250;
uint16_t PrescalerValue = 0;

void TIM_Config(void);


int main(void)
{

  /* TIM Configuration */
   TIM_Config();

  PrescalerValue = (uint16_t) ((SystemCoreClock /2) / 28000000) - 1;

  /* Time base configuration */
  TIM_TimeBaseStructure.TIM_Period = 665;
  TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);



  /* PWM1 Mode configuration: Channel1 */
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = CCR1_Val;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

  TIM_OC1Init(TIM1, &TIM_OCInitStructure);
  TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable);

   


  TIM_ARRPreloadConfig(TIM1, ENABLE);


  /* TIM 1 enable counter */
  TIM_Cmd(TIM1, ENABLE);
 

  while (1)
  {}

}


void TIM_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  /* TIM1 clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
 
  /* GPIOA clock enable */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
 
  /* GPIOC Configuration: TIM1 CH1 (PA8) */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8  ;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP ;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
 

  /* Connect TIM1 pins to AF2 */  
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_TIM1);
                                                            
}

#ifdef  USE_FULL_ASSERT

/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t* file, uint32_t line)
{
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

  while (1)
  {}
}
#endif

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