stm32f407,pwm实验疑问,为什么这个程序在示波器上的波形是乱的

lllcc · 发表于 2021-3-21 13:20:04

我把教程视频里的pwm输出实验的程序换了时钟和io口，为什么外接硬木课堂示波器却不是pwm波呢？
void TIM1_PWM_Init(u32 arr,u32 psc)
{

GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1,ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);

GPIO_PinAFConfig(GPIOE,GPIO_PinSource9,GPIO_AF_TIM1);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOE,&GPIO_InitStructure);

TIM_TimeBaseStructure.TIM_Prescaler=psc;
TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_Period=arr;
TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;

TIM_TimeBaseInit(TIM1,&TIM_TimeBaseStructure);

//3õê¼»ˉTIM14 Channel1 PWMÄ￡ê½
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
TIM_OC1Init(TIM3, &TIM_OCInitStructure);

TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable);
  TIM_ARRPreloadConfig(TIM1,ENABLE);
TIM_Cmd(TIM1, ENABLE);


}

主函数
int main(void)
{
u16 led0pwmval=0;
u8 dir=1;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
delay_init(168);
uart_init(115200);
TIM1_PWM_Init(500-1,84-1);
while(1)
{
delay_ms(10);
if(dir)led0pwmval++;
else led0pwmval--;
if(led0pwmval>300)dir=0;
if(led0pwmval==0)dir=1;

TIM_SetCompare1(TIM1,led0pwmval);
}