pwm初始化的问题

chenshoubao

在pwm初始化函数里面，TIM_OC1Init初始化了TIM_Pulse这个变量。但是在TIM_OC1Init函数定义里面，并没有TIM_Pulse这个变量。什么时候该定义，什么时候该不定义呢?

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //选择定时器模式:TIM脉冲宽度调制模式2
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能
TIM_OCInitStructure.TIM_Pulse = 0; //设置待装入捕获比较寄存器的脉冲值
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出极性:TIM输出比较极性高
TIM_OC1Init(TIM1, &TIM_OCInitStructure);  //根据TIM_OCInitStruct中指定的参数初始化外设TIMx

void TIM_OC1Init(TIM_TypeDef* TIMx, TIM_OCInitTypeDef* TIM_OCInitStruct)
{
  uint16_t tmpccmrx = 0, tmpccer = 0, tmpcr2 = 0;
   
  /* Check the parameters */
  assert_param(IS_TIM_LIST8_PERIPH(TIMx));
  assert_param(IS_TIM_OC_MODE(TIM_OCInitStruct->TIM_OCMode));
  assert_param(IS_TIM_OUTPUT_STATE(TIM_OCInitStruct->TIM_OutputState));
  assert_param(IS_TIM_OC_POLARITY(TIM_OCInitStruct->TIM_OCPolarity));   
 /* Disable the Channel 1: Reset the CC1E Bit */
  TIMx->CCER &= (uint16_t)(~(uint16_t)TIM_CCER_CC1E);
  /* Get the TIMx CCER register value */
  tmpccer = TIMx->CCER;
  /* Get the TIMx CR2 register value */
  tmpcr2 =  TIMx->CR2;
  
  /* Get the TIMx CCMR1 register value */
  tmpccmrx = TIMx->CCMR1;
    
  /* Reset the Output Compare Mode Bits */
  tmpccmrx &= (uint16_t)(~((uint16_t)TIM_CCMR1_OC1M));
  tmpccmrx &= (uint16_t)(~((uint16_t)TIM_CCMR1_CC1S));

  /* Select the Output Compare Mode */
  tmpccmrx |= TIM_OCInitStruct->TIM_OCMode;
  
  /* Reset the Output Polarity level */
  tmpccer &= (uint16_t)(~((uint16_t)TIM_CCER_CC1P));
  /* Set the Output Compare Polarity */
  tmpccer |= TIM_OCInitStruct->TIM_OCPolarity;
  
  /* Set the Output State */
  tmpccer |= TIM_OCInitStruct->TIM_OutputState;
    
  if((TIMx == TIM1) || (TIMx == TIM8)|| (TIMx == TIM15)||
     (TIMx == TIM16)|| (TIMx == TIM17))
  {
    assert_param(IS_TIM_OUTPUTN_STATE(TIM_OCInitStruct->TIM_OutputNState));
    assert_param(IS_TIM_OCN_POLARITY(TIM_OCInitStruct->TIM_OCNPolarity));
    assert_param(IS_TIM_OCNIDLE_STATE(TIM_OCInitStruct->TIM_OCNIdleState));
    assert_param(IS_TIM_OCIDLE_STATE(TIM_OCInitStruct->TIM_OCIdleState));
    
    /* Reset the Output N Polarity level */
    tmpccer &= (uint16_t)(~((uint16_t)TIM_CCER_CC1NP));
    /* Set the Output N Polarity */
    tmpccer |= TIM_OCInitStruct->TIM_OCNPolarity;
    
    /* Reset the Output N State */
    tmpccer &= (uint16_t)(~((uint16_t)TIM_CCER_CC1NE));    
    /* Set the Output N State */
    tmpccer |= TIM_OCInitStruct->TIM_OutputNState;
    
    /* Reset the Output Compare and Output Compare N IDLE State */
    tmpcr2 &= (uint16_t)(~((uint16_t)TIM_CR2_OIS1));
    tmpcr2 &= (uint16_t)(~((uint16_t)TIM_CR2_OIS1N));
    
    /* Set the Output Idle state */
    tmpcr2 |= TIM_OCInitStruct->TIM_OCIdleState;
    /* Set the Output N Idle state */
    tmpcr2 |= TIM_OCInitStruct->TIM_OCNIdleState;
  }

lycreturn

TIM_Pulse  这个用于设置CCRx的是   
在TIM_OC1Init函数里倒数第二句有设置的  TIMx->CCR1 = TIM_OCInitStruct->TIM_Pulse;  
 上面你没有把TIM_OC1Init函数的全部内容贴出来   后面还有几句
/* Write to TIMx CR2 */
  TIMx->CR2 = tmpcr2;
  
  /* Write to TIMx CCMR1 */
  TIMx->CCMR1 = tmpccmrx;

  /* Set the Capture Compare Register value */
  TIMx->CCR1 = TIM_OCInitStruct->TIM_Pulse; 
 
  /* Write to TIMx CCER */
  TIMx->CCER = tmpccer;

chenshoubao

回复【2楼】lycreturn:
---------------------------------
大神 谢谢了