void TIM2_PWM_Init(uint32_t arr,uint32_t psc)
{
//此部分需手动修改IO口设置
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE); //TIM2时钟使能
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE); //使能PORTA时钟
GPIO_PinAFConfig(GPIOA,GPIO_PinSource0,GPIO_AF_TIM2); //GPIOA0复用为定时器2
GPIO_PinAFConfig(GPIOA,GPIO_PinSource1,GPIO_AF_TIM2); //GPIOA1复用为定时器2
GPIO_PinAFConfig(GPIOA,GPIO_PinSource2,GPIO_AF_TIM2); //GPIOA2复用为定时器2
GPIO_PinAFConfig(GPIOA,GPIO_PinSource3,GPIO_AF_TIM2); //GPIOA3复用为定时器2
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_2|GPIO_Pin_3; //GPIOFA
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; //复用功能
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; //速度100MHz
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //推挽复用输出
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; //上拉
GPIO_Init(GPIOA,&GPIO_InitStructure); //初始化
TIM_TimeBaseStructure.TIM_Prescaler=psc; //定时器分频
TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //向上计数模式
TIM_TimeBaseStructure.TIM_Period=arr; //自动重装载值
TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;
TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructure);//初始化定时器2
//初始化TIM3 PWM模式
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //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_Low; //输出极性:TIM输出比较极性低
TIM_OC1Init(TIM2, &TIM_OCInitStructure); //根据T指定的参数初始化外设TIM2 4OC1
TIM_OC2Init(TIM2, &TIM_OCInitStructure); //根据T指定的参数初始化外设TIM2 4OC1
TIM_OC3Init(TIM2, &TIM_OCInitStructure); //根据T指定的参数初始化外设TIM2 4OC1
TIM_OC4Init(TIM2, &TIM_OCInitStructure); //根据T指定的参数初始化外设TIM2 4OC1
TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Enable); //使能TIM2在CCR1上的预装载寄存器
TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Enable); //使能TIM2在CCR1上的预装载寄存器
TIM_OC3PreloadConfig(TIM2, TIM_OCPreload_Enable); //使能TIM2在CCR1上的预装载寄存器
TIM_OC4PreloadConfig(TIM2, TIM_OCPreload_Enable); //使能TIM2在CCR1上的预装载寄存器
TIM_ARRPreloadConfig(TIM2,ENABLE);//ARPE使能
TIM_Cmd(TIM2, ENABLE); //使能TIM2
}
int main(void)
{
TIM2_PWM_Init(210-1,100-1);//4KHz
TIM_SetCompare1(TIM2,100); //修改比较值,修改占空比 //A B轮
TIM_SetCompare2(TIM2,500); //修改比较值,修改占空比
TIM_SetCompare3(TIM2,800); //修改比较值,修改占空比
TIM_SetCompare4(TIM2,900); //修改比较值,修改占空比
}
首先要知道定时器的时钟频率,不清楚的可以去CubeMX查看,
PWM的频率=定时器时钟 / TIM_Prescaler / TIM_Period
PWM占空比=TIM_Pulse / TIM_Period
我们可以通过修改此函数来改变TIM_Pulse的值,如下
TIM_SetCompare4(TIM2,900); //设置TIM2的4通道的比较值为900
如:本文使用的是TIM2
TIM1和TIM8是挂载在APB2总线,时钟168MHz
而TIM2是挂载在APB1总线,时钟84MHz
频率=时钟/arr/psc
如84000000/210/100=4000即4KHz