三、具体代码：
- int main(void) //主函数
- {undefined
- delay_init(); //延时函数初始化
- uart_init(9600); //串口初始化
- TIM4_PWM_Init(999,7199); //TIM4 PWM输出初始化
- TIM3_Interrupt_Init(999,7199); //TIM3定时器中断初始化
- pwmval= 600; //占空比
- while(1) ；
- }
- void TIM4_PWM_Init(u16 arr,u16 psc) //TIM4 定时器PWM输出功能初始化函数
- {
- GPIO_InitTypeDef GPIO_InitStructure;
- TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
- TIM_OCInitTypeDef TIM_OCInitStructure;
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);//使能GPIO外设和AFIO复用功能模块时钟使能
- GPIO_InitStructure.GPIO_Pin = /*GPIO_Pin_6 | GPIO_Pin_7|*/GPIO_Pin_8 | GPIO_Pin_9;
- 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);
- 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 80K
- TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值 不分频
- 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(TIM4, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位
- TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //PWM模式2
- TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //正向通道有效
- TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable; //反向通道无效
- TIM_OCInitStructure.TIM_Pulse = 0; //占空时间
- // TIM_OC1Init(TIM4,&TIM_OCInitStructure); //通道1
- // TIM_OC1PreloadConfig(TIM4, TIM_OCPreload_Enable);
- // TIM_OC2Init(TIM4,&TIM_OCInitStructure); //通道2
- // TIM_OC2PreloadConfig(TIM4, TIM_OCPreload_Enable);
- TIM_OC3Init(TIM4, &TIM_OCInitStructure); //使能通道3
- TIM_OC3PreloadConfig(TIM4, TIM_OCPreload_Enable);
- TIM_OC4Init(TIM4, &TIM_OCInitStructure); //使能通道4
- TIM_OC4PreloadConfig(TIM4, TIM_OCPreload_Enable);
- TIM_CtrlPWMOutputs(TIM4,ENABLE);
- TIM_ARRPreloadConfig(TIM4, ENABLE); //使能TIMx在ARR上的预装载寄存器
- TIM_Cmd(TIM4, ENABLE); //使能TIMx外设
- }
- void TIM3_Interrupt_Init(u16 arr,u16 psc) //TIM3定时器中断功能初始化函数
- {undefined
- TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
- NVIC_InitTypeDef NVIC_InitStructure;
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //时钟使能
- 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 计数到5000为500ms
- TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值 10Khz的计数频率
- 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
- TIM_ITConfig(TIM3,TIM_IT_Update | TIM_IT_Trigger,ENABLE);
- NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn; //TIM3中断
- NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; //抢占优先级0级
- NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; //相应优先级3级
- NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能
- NVIC_Init(&NVIC_InitStructure); //根据NVIC_InitStruct中指定的参数初始化外设NVIC寄存器
- TIM_Cmd(TIM3, ENABLE); //使能TIMx外设
- }
- void TIM3_IRQHandler(void) //TIM3中断服务函数
- {
- if(TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET) //检查指定的TIM中断发生与否:TIM 中断源
- {undefined
- ++Event;
- if(Event == 1)
- {undefined
- TIM_SetCompare3(TIM4,(led0pwmval*80)/100);
- }
- if(Event == 2)
- {undefined
- Event = 0;
- TIM_SetCompare3(TIM4,(led0pwmval*20)/100);
- }
- TIM_ClearITPendingBit(TIM3, TIM_IT_Update); //清除TIMx的中断待处理位:TIM 中断源
- }
- }
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