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- 2020-10-21
- 在线时间
- 5 小时
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发表于 2020-10-21 11:42:46
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- /*---------------main.c-----------------*/
- //截取我的项目里面的部分代码,头文件自己建
- int main(void)
- {
- //pwm波形 可用示波器测量
- TIM3_Init(899,0);//不分频。PWM频率=72000/(899+1)=80Khz
- TIM3_PWM_Init();
-
- while(1)
- {
- }
- }
- /*---------------tim.c-----------------*/
- // TIM3-CH2
- //注意是全映射还是部分映射 GPIO_PinRemapConfig(GPIO_FullRemap_TIM3, ENABLE); 在PA7上使用TIM3需要全映射
- void TIM3_Init(u16 arr,u16 psc)
- {
-
- NVIC_InitTypeDef NVIC_InitStructure;
- TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
-
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC|RCC_APB2Periph_AFIO, ENABLE);
- GPIO_PinRemapConfig(GPIO_FullRemap_TIM3, ENABLE);
-
-
- //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
-
- NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
- NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn ;
- NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
- NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;
- NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
- NVIC_Init(&NVIC_InitStructure);
- TIM_Cmd(TIM3, ENABLE);
- }
- /*---------------pwm.c-----------------*/
- /*
- PA.7
- */
- //PWM输出初始化
- //arr:自动重装值
- //psc:时钟预分频数
- void TIM3_PWM_Init()
- {
- GPIO_InitTypeDef GPIO_InitStructure;
- TIM_OCInitTypeDef TIM_OCInitStructure;
-
- //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_7; //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(GPIOC, &GPIO_InitStructure);//初始化GPIO
-
- //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_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable); //使能TIM3在CCR2上的预装载寄存器
- TIM_Cmd(TIM3, ENABLE); //使能TIM3
-
- TIM_SetCompare2(TIM3,450); //输出pwm 占空比 = 450/arr
-
- }
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