stm32定時器--通道pwm輸出參數TIM_OCInitStructure如何配置

設置定時器的pwm輸出時需配置TIM_OCInitTypeDef結構體的參數，輸入捕獲是用TIM_ICInitTypeDef結構體。

typedef struct
{
  uint16_t TIM_OCMode;      //

  uint16_t TIM_OutputState;  //輸出狀態 

  uint16_t TIM_OutputNState;  //互補通道的輸出狀態

  uint16_t TIM_Pulse;   //佔空比      

  uint16_t TIM_OCPolarity;  //輸出極性

  uint16_t TIM_OCNPolarity; //互補通道的輸出極性

  uint16_t TIM_OCIdleState;  //空閒狀態

  uint16_t TIM_OCNIdleState; //互補通道的空閒狀態
} TIM_OCInitTypeDef;

互補通道的參數都有，如果像只用一個通道比如用的T15_CH1N,則配置帶N的參數，注意參數值也要選帶N的，TIM_OCPolarity_Low和TIM_OCNPolarity_Low值是不一樣的，不能混用，因爲對應寄存器的控制位不一樣。

    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;             //TIM脈衝寬度調製模式1
    TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable; //比較輸出使能
    TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;     //輸出極性:TIM輸出比較極性低    
    TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCNIdleState_Reset;//輸出空閒狀態
    TIM_OCInitStructure.TIM_Pulse =ChannelPulse;   //佔空比           
    TIM_OC1Init(TIM15, &TIM_OCInitStructure);    

比如T3_CH2:

    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //TIM脈衝寬度調製模式2
     TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比較輸出使能
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //輸出極性:TIM輸出比較極性高
    TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Reset; //空閒狀態，低電平

    TIM_OCInitStructure.TIM_Pulse = ChannelPulse;//佔空比
    TIM_OC2Init(TIM3, &TIM_OCInitStructure);

TIM_OCInitStructure的參數配置不涉及通道，通道的選擇就是靠TIM_OCxInit區分。

先看第一個參數：TIM_OCMode對應寄存器CCMR1的6：4位:

主要看TIM_OCMode_PWM1 和 TIM_OCMode_PWM2的區別

#define TIM_OCMode_PWM1                    ((uint16_t)0x0060)即6：4=110
#define TIM_OCMode_PWM2                    ((uint16_t)0x0070) 即6：4=111

那誰是有效電平呢？看寄存器CCER

對應這兩句：

TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;//有效電平爲高電平，即輸出極性CC2P=0

TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比較輸出使能，即CC2E=1

還有最後一個參數：TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Reset;對應CR2的第8位：

#define TIM_OCIdleState_Set                ((uint16_t)0x0100)  
#define TIM_OCIdleState_Reset              ((uint16_t)0x0000)

知道了定義後看看定時器3的設置會產生什麼樣的波形：（TIM_OCMode_PWM2，TIM_OCPolarity_High，佔空比30%）

佔空比30%對應的計數值ChannelPulse = (uint16_t) (((uint32_t) 30 * (週期計數值-1)) / 100);

（TIM_OCMode_PWM1，TIM_OCPolarity_High，佔空比30%）

（TIM_OCMode_PWM1，TIM_OCPolarity_Low，佔空比30%）

（TIM_OCMode_PWM2，TIM_OCPolarity_Low，佔空比30%）

附完整的定時器初始化（stm32f072的PA1引腳對應T15_CH1N）：

/*
PA1--AF5--TIM15CH1N
**************************************************************************
*/
void TIM15_PWM_Init(void)
{	
    uint16_t ChannelPulse = 0,PWM_TimerPeriod; 
    
	GPIO_InitTypeDef         GPIO_InitStructure;
	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
	TIM_OCInitTypeDef        TIM_OCInitStructure;
	NVIC_InitTypeDef NVIC_InitStructure;	
    //引腳初始化
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM15 , ENABLE);  
	RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);//使能GPIOA時鐘和複用功能時鐘	
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1; //TIM2二通道PWM波形輸出端口PA1			 
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
	GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;//設置引腳爲推輓輸出
	GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; 	//設置引腳爲上拉		
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;	//設置引腳速度爲50MHZ
	GPIO_Init(GPIOA, &GPIO_InitStructure);
	GPIO_PinAFConfig(GPIOA, GPIO_PinSource1, GPIO_AF_5);	
    
    /* 
        系統時鐘48mhz，要實現150us週期，即6.67khz，48m/6.67k=7196 
         48M/4800=10khz
    */
	PWM_TimerPeriod = (unsigned int)( 4800 ) - 1;
    ChannelPulse = (uint16_t) (((uint32_t) 95 * (PWM_TimerPeriod - 1)) / 100);//佔空比5%	
	/* Time 定時基礎設置*/
	TIM_TimeBaseStructure.TIM_Prescaler = 0;
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  /* Time 定時設置爲上升沿計算模式*/
	TIM_TimeBaseStructure.TIM_Period = PWM_TimerPeriod;
	TIM_TimeBaseStructure.TIM_ClockDivision = 0;
	TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
	TIM_TimeBaseInit(TIM15, &TIM_TimeBaseStructure);	
	TIM_ARRPreloadConfig(TIM15, ENABLE);
    
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;             //TIM脈衝寬度調製模式1
	TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable; //比較輸出使能
	TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;     //輸出極性:TIM輸出比較極性低	
    TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCNIdleState_Reset;//輸出空閒狀態
	TIM_OCInitStructure.TIM_Pulse =ChannelPulse;               //設置待裝入捕獲比較寄存器的脈衝值,取值必須在0x0000~0xFFFF之間
	TIM_OC1Init(TIM15, &TIM_OCInitStructure);          //根據TIM_OCInitStruct中指定的參數初始化外設TIMx
    
	TIM_OC1PreloadConfig(TIM15, TIM_OCPreload_Enable); //使能TIMx在CCR1上的預裝載寄存器	
	TIM_Cmd(TIM15, ENABLE);
  /* TIM1 Main Output Enable */
  TIM_CtrlPWMOutputs(TIM15, ENABLE);	
}

stm32f103的TIM3_CH2對應引腳PB5初始化：

//arr：自動重裝值
//psc：時鐘預分頻數
void TIM3_PWM_Init(u16 arr,u16 psc)
{ 
    uint16_t ChannelPulse = 0;    
	GPIO_InitTypeDef GPIO_InitStructure;
	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
	TIM_OCInitTypeDef  TIM_OCInitStructure;
	
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);	//使能定時器3時鐘
 	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB  | RCC_APB2Periph_AFIO, ENABLE);  //使能GPIO外設和AFIO複用功能模塊時鐘	
	GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3部分重映射  TIM3_CH2->PB5    
 
   //設置該引腳爲複用輸出功能,輸出TIM3 CH2的PWM脈衝波形	GPIOB.5
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //TIM_CH2
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;  //複用推輓輸出
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOB, &GPIO_InitStructure);//初始化GPIO
    ChannelPulse = (uint16_t) (((uint32_t) 30 * (arr+1)) / 100);//佔空比30%
   //初始化TIM3
	TIM_TimeBaseStructure.TIM_Period = arr; //設置在下一個更新事件裝入活動的自動重裝載寄存器週期的值
	TIM_TimeBaseStructure.TIM_Prescaler =psc; //設置用來作爲TIMx時鐘頻率除數的預分頻值 
	TIM_TimeBaseStructure.TIM_ClockDivision = 0; //設置時鐘分割:TDTS = Tck_tim
	TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM向上計數模式
	TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //根據TIM_TimeBaseInitStruct中指定的參數初始化TIMx的時間基數單位
	TIM_ARRPreloadConfig(TIM3, ENABLE);	
	//初始化TIM3 Channel2 PWM模式	 
	TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //選擇定時器模式:TIM脈衝寬度調製模式2
 	TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比較輸出使能
	TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //輸出極性:TIM輸出比較極性高
    TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Reset;
    TIM_OCInitStructure.TIM_Pulse = ChannelPulse;
	TIM_OC2Init(TIM3, &TIM_OCInitStructure);  //根據T指定的參數初始化外設TIM3 OC2

	TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);  //使能TIM3在CCR2上的預裝載寄存器
	TIM_Cmd(TIM3, ENABLE);  //使能TIM3	
}