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PWM not work by using TIM10_CH1

Question asked by su.black on Sep 4, 2013
Latest reply on Sep 4, 2013 by Clive One
My platform's MCU is STM32f205.
I try to modify TIM10_PWMOutput example from STM32F2xx Standard Peripherals Firmware Library to generate one PWM signal by using TIM10_CH1function of pin PB8. But it doesn't work? Can somebody help me to fix this issue? please see the reference codes as below.

int main(void)
{
  /* TIM Configuration */
  TIM_Config();
 
  /* ---------------------------------------------------------------------------
    TIM10 Configuration: generate 1 PWM signal:
    
    In this example TIM10 input clock (TIM10CLK) is set to 2 * APB2 clock (PCLK2),
    since APB2 prescaler is different from 1.   
      TIM10CLK = 2 * PCLK2  
      PCLK2 = HCLK / 2
      => TIM10CLK = HCLK = SystemCoreClock
          
    To get TIM10 counter clock at 20 MHz, the prescaler is computed as follows:
       Prescaler = (TIM10CLK / TIM10 counter clock) - 1
       Prescaler = (SystemCoreClock /20 MHz) - 1
                                              
    To get TIM10 output clock at 30 KHz, the period (TIM10_ARR) is computed as follows:
       ARR = (TIM10 counter clock / TIM10 output clock) - 1
           = 665
                  
    TIM10 Channel1 duty cycle = (TIM10_CCR1/ TIM10_ARR)* 100 = 50%

    Note:
     SystemCoreClock variable holds HCLK frequency and is defined in system_stm32f2xx.c file.
     Each time the core clock (HCLK) changes, user had to call SystemCoreClockUpdate()
     function to update SystemCoreClock variable value. Otherwise, any configuration
     based on this variable will be incorrect.    
  --------------------------------------------------------------------------- */   


  /* Compute the prescaler value */
  PrescalerValue = (uint16_t) (SystemCoreClock / 20000000) - 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(TIM10, &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(TIM10, &TIM_OCInitStructure);

  TIM_OC1PreloadConfig(TIM10, TIM_OCPreload_Enable);

  TIM_ARRPreloadConfig(TIM10, ENABLE);

  /* TIM10 enable counter */
  TIM_Cmd(TIM10, ENABLE);

  while (1)
  {}
}

/**
  * @brief  Configure the TIM10 Ouput Channels.
  * @param  None
  * @retval None
  */
void TIM_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
 
  /* TIM10 clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM10, ENABLE);

  /* GPIOF clock enable */
  //RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOF, ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
 
  /* GPIOF Configuration: TIM10 CH1 (PF6) */
  //GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 ;
    /* GPIOF Configuration: TIM10 CH1 (PB8) */
  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(GPIOF, &GPIO_InitStructure);
    GPIO_Init(GPIOB, &GPIO_InitStructure);

  /* Connect TIM pins to AF3 */
  //GPIO_PinAFConfig(GPIOF, GPIO_PinSource6, GPIO_AF_TIM10);
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource8, GPIO_AF_TIM10);
}

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