原子哥,我用库函数版本写的TIM3_CH1的PWM波怎么出不来啊?代码如下:
time.c文件
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
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);
// GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3部分重映射 TIM3_CH2->  B5
/*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(GPIOA, &GPIO_InitStructure); //初始化GPIO
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6; //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(GPIOA, &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,TIM3时钟为72MHZ
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_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
}
main.c文件
int main(void)
{
u16 led0pwmval=2500;
u8 dir=1;
delay_init(); //延时函数初始化
NVIC_Configuration(); //设置NVIC中断分组2:2位抢占优先级,2位响应优先级
//uart_init(9600); //串口初始化为9600
LED_Init(); //LED端口初始化
TIM3_PWM_Init(4999,7199); //PWM频率=72000000/(5000*7200)=2hz,周期=0.5s
TIM_SetCompare2(TIM3,led0pwmval);//占空比50%
TIM_SetCompare1(TIM3,led0pwmval);//占空比50%
while(1);
//{
//delay_ms(10);
//if(dir)led0pwmval++;
//else led0pwmval--;
//if(led0pwmval>300)dir=0;
//if(led0pwmval==0)dir=1;
//TIM_SetCompare2(TIM3,led0pwmval);
//}
}
CH2的PWM波可以出来,但是CH1出不来啊,这是怎么回事呢?
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