求指导：关于stm32f105的TIM1+PWM输出的配置

只看该作者 · 2012-2-10 10:35

如题：我的代码如下，就是不出PWM波形。求高手指导
void Tim1Init()
{

  RCC_ClocksTypeDef RCC_ClocksStatus;
  GPIO_InitTypeDef GPIO_InitStructure;
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
  TIM_OCInitTypeDef       TIM_OCInitStructure;

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_GPIOA, ENABLE);

/* Configure  pa8 as ouput -------------------------*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Get HCLK Information 返回时钟频率          */
  RCC_GetClocksFreq(&RCC_ClocksStatus);

  TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
  TIM_TimeBaseStructure.TIM_Period = 0xFF;
  TIM_TimeBaseStructure.TIM_Prescaler = 0x4;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = 0x7F;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
  TIM_OC1Init(TIM1, &TIM_OCInitStructure);

  TIM_CtrlPWMOutputs(TIM1, ENABLE);
  TIM_ARRPreloadConfig(TIM1, ENABLE);
  TIM_Cmd(TIM1, ENABLE);

}