關(guān)于stm32定時(shí)器的理解
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
表面意思是輸出控制極性為高，但是意思是定時(shí)器輸入0，不反相，輸出0；
輸出控制極性為低，定時(shí)器輸入0，反相輸出1；
CC1E控制開關(guān)。
#define TIM_OCPolarity_High ((uint16_t)0x0000)
#define TIM_OCPolarity_Low ((uint16_t)0x0002)
定時(shí)器通道寫法： TIM_OC2 意思是定時(shí)器channel 2 ，TIM_OC1意思是定時(shí)器通道1.
//小波Linux
pwm占空比：
TIM_SetCompare1(TIM2,led1pwmval);
TIM_SetCompare2(TIM3,led0pwmval);
TIMX為哪個(gè)定時(shí)器，ledxpwmval為占空比的值；
TIM2_PWM_Init(899,0); //不分頻 72000/900=8Khz
arr 自動(dòng)重裝載計(jì)數(shù)器初值 900 =899+1；
占空比例如 占 50% = 450 / 900
ledxpwmval = 450;
定時(shí)器初始化，里面有個(gè)重映射
void TIM2_PWM_Init(u16 arr,u16 psc) {
GPIO_InitTypeDef GPIO_InitStructure; TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; TIM_OCInitTypeDef TIM_OCInitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);//使能定時(shí)器3時(shí)鐘 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE); //使能GPIO外設(shè)和AFIO復(fù)用功能模塊時(shí)鐘 //設(shè)置該引腳為復(fù)用輸出功能,輸出TIM2 CH1的PWM脈沖波形 PA0 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0; //TIM_CH1 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //復(fù)用推挽輸出 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIO //初始化TIM2 TIM_TimeBaseStructure.TIM_Period = arr; //設(shè)置在下一個(gè)更新事件裝入活動(dòng)的自動(dòng)重裝載寄存器周期的值 TIM_TimeBaseStructure.TIM_Prescaler =psc; //設(shè)置用來作為TIMx時(shí)鐘頻率除數(shù)的預(yù)分頻值 TIM_TimeBaseStructure.TIM_ClockDivision = 0; //設(shè)置時(shí)鐘分割:TDTS = Tck_tim TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上計(jì)數(shù)模式 TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure); //根據(jù)TIM_TimeBaseInitStruct中指定的參數(shù)初始化TIMx的時(shí)間基數(shù)單位 //初始化TIM2 Channel 1 PWM模式 TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //選擇定時(shí)器模式:TIM脈沖寬度調(diào)制模式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_OC1Init(TIM2, &TIM_OCInitStructure); //根據(jù)T指定的參數(shù)初始化外設(shè)TIM2 OC1
TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Enable); //使能TIM2在CCR1上的預(yù)裝載寄存器 TIM_Cmd(TIM2, ENABLE); //使能TIM2
}
//TIM3 PWM部分初始化 //PWM輸出初始化 //arr：自動(dòng)重裝值 //psc：時(shí)鐘預(yù)分頻數(shù) void TIM3_PWM_Init(u16 arr,u16 psc) { GPIO_InitTypeDef GPIO_InitStructure; TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; TIM_OCInitTypeDef TIM_OCInitStructure; RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);//使能定時(shí)器3時(shí)鐘 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB " RCC_APB2Periph_AFIO, ENABLE); //使能GPIO外設(shè)和AFIO復(fù)用功能模塊時(shí)鐘 GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3部分重映射 TIM3_CH2->PB5 //設(shè)置該引腳為復(fù)用輸出功能,輸出TIM3 CH2的PWM脈沖波形GPIOB.5 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //TIM_CH2 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //復(fù)用推挽輸出 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOB, &GPIO_InitStructure);//初始化GPIO //初始化TIM3 TIM_TimeBaseStructure.TIM_Period = arr; //設(shè)置在下一個(gè)更新事件裝入活動(dòng)的自動(dòng)重裝載寄存器周期的值 TIM_TimeBaseStructure.TIM_Prescaler =psc; //設(shè)置用來作為TIMx時(shí)鐘頻率除數(shù)的預(yù)分頻值 TIM_TimeBaseStructure.TIM_ClockDivision = 0; //設(shè)置時(shí)鐘分割:TDTS = Tck_tim TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上計(jì)數(shù)模式 TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //根據(jù)TIM_TimeBaseInitStruct中指定的參數(shù)初始化TIMx的時(shí)間基數(shù)單位 //初始化TIM3 Channel2 PWM模式 TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //選擇定時(shí)器模式:TIM脈沖寬度調(diào)制模式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_OC2Init(TIM3, &TIM_OCInitStructure); //根據(jù)T指定的參數(shù)初始化外設(shè)TIM3 OC2
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable); //使能TIM3在CCR2上的預(yù)裝載寄存器 TIM_Cmd(TIM3, ENABLE); //使能TIM3
}
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