STM32——TIM1的TIM1_CH1N通道PWM初始化

TIM1 是 STM32 的高級定時器，功能很強大，它的每個通道都有對應的互補通道用來互補輸出PWM。之前沒使用過，今天要用來做 PWM 控制，花了好一番功夫才搞定。

• 記錄下初始化代碼：

void  Led_PWM_Init(u16 arr, u32 ckCnt, u16 CCR1_Val)
{
    uint16_t pscValue = 0;
  
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef       TIM_OCInitStructure;
    NVIC_InitTypeDef        NVIC_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);   

    GPIO_Config();                              //PWM控制引腳初始化

    TIM_DeInit(TIM1);

    /* Time Base configuration */
    pscValue = (uint16_t)(SystemCoreClock / ckCnt) - 1;
    TIM_TimeBaseStructure.TIM_Prescaler         = pscValue ;
    TIM_TimeBaseStructure.TIM_CounterMode       = TIM_CounterMode_Up;
    TIM_TimeBaseStructure.TIM_Period            = arr;
    TIM_TimeBaseStructure.TIM_ClockDivision     = 0;
    TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;    //高級定時器特有

    TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

    /* Channel 1, 2,3 and 4 Configuration in PWM mode */
    TIM_OCInitStructure.TIM_OCMode             = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState        = TIM_OutputState_Disable;
//    TIM_OCInitStructure.TIM_OCPolarity         = TIM_OCPolarity_High;
	TIM_OCInitStructure.TIM_OCIdleState        = TIM_OCIdleState_Reset;
	
    TIM_OCInitStructure.TIM_OutputNState       = TIM_OutputNState_Enable;    
    TIM_OCInitStructure.TIM_OCNPolarity        = TIM_OCNPolarity_High;
  
    TIM_OCInitStructure.TIM_OCNIdleState       = TIM_OCNIdleState_Set;

    TIM_OCInitStructure.TIM_Pulse                   = CCR1_Val;                      //佔空比
    TIM_OC1Init(TIM1, &TIM_OCInitStructure);

    TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable);

    TIM_ARRPreloadConfig(TIM1, ENABLE);

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

高級定時器做PWM的話和其他定時器一樣的使用。只是配置不一樣。
對於高級定時器來說，要有這句TIM_CtrlPWMOutputs(TIM1, ENABLE);使能PWM輸出。
由於只是使用TIM1的通道1的互補通道，所以關閉通道1的 PWM 輸出

    TIM_OCInitStructure.TIM_OutputState        = TIM_OutputState_Disable;

打開通道1的互補通道的PWM的輸出

  TIM_OCInitStructure.TIM_OutputNState       = TIM_OutputNState_Enable;  

百度和對照別人的代碼，搞了好久也沒搞定不能控制亮度。後來發現是沒有這句

TIM_OCInitStructure.TIM_OCIdleState        = TIM_OCIdleState_Reset;

上面這句要和下面這句設置相反：
一個是TIM_OCIdleState_Reset、另一個是TIM_OCNIdleState_Set

  TIM_OCInitStructure.TIM_OCNIdleState       = TIM_OCNIdleState_Set;