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如题,原子的历程是用TIM3部分复用,用PB8输出PWM波形,部分不用的话是将CH2给到了PB5;CH1给到了PB4。为什么我只有PB5有波形输出,PB4没有,代码如下,求解~
- int main(void)
- {
- NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); //设置NVIC中断分组2:2位抢占优先级,2位响应优先级
- TIM3_PWM_Init(899,0); //不分频。PWM频率=72000000/900=80Khz
- while(1)
- {
- TIM_SetCompare2(TIM3,300);
- TIM_SetCompare1(TIM3,300);
- }
- }
-
- 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); //使能定时器3时钟
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE); //使能GPIO外设和AFIO复用功能模块时钟
-
- GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3部分重映射
-
- //设置该引脚为复用输出功能,输出TIM3 CH2的PWM脉冲波形 GPIOB.5
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //TIM_CH2
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_Init(GPIOB, &GPIO_InitStructure);//初始化GPIO
-
- //设置该引脚为复用输出功能,输出TIM3 CH2的PWM脉冲波形 GPIOB.4
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4; //TIM_CH1
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出
- 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; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值
- TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值
- TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_tim
- TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上计数模式
- TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位
-
- //初始化TIM3 Channel2 PWM模式
- 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_OCPolarity = TIM_OCPolarity_High; //输出极性:TIM输出比较极性高
- TIM_OC2Init(TIM3, &TIM_OCInitStructure); //根据T指定的参数初始化外设TIM3 OC2
- TIM_OC1Init(TIM3, &TIM_OCInitStructure); //根据T指定的参数初始化外设TIM3 OC1
- TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable); //使能TIM3在CCR2上的预装载寄存器
- TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable); //使能TIM3在CCR1上的预装载寄存器
-
- TIM_Cmd(TIM3, ENABLE); //使能TIM3
- }
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