STM32F4第33讲视频PWM输出实验跟着教程视频，感觉内容写的差不多但是为啥下载的效果和原码不一致

SSSAZas · 发表于 2020-7-31 21:25:14

主函数是这样
int main(void)
{
  u16  pwm_ccr=0;
  u8 pwm_sym=1;
  delay_init(168);
  uart_init(115200);
TIM14_PWM_Init(500-1,84-1);
while(1)
{
delay_ms(10);
if(pwm_sym) pwm_ccr++;
else pwm_ccr--;
if(pwm_ccr>300) pwm_sym=0;
if(pwm_ccr==0) pwm_sym=1;
TIM_SetCompare1(TIM14,pwm_ccr);
}

}
pwm.h文件是照着视频讲解的内容去写的
void TIM14_PWM_Init(u32 arr,u32 psc)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM14,ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOF,ENABLE);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;          //GPIOF9
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;       //¸′óÃ1|Äü
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; //Ëù¶è100MHz
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;    //íÆíì¸′óÃêä3ö
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;       //éÏà-
GPIO_Init(GPIOF,&GPIO_InitStructure);             //3õê¼»ˉPF9

GPIO_PinAFConfig(GPIOF,GPIO_PinSource9,GPIO_AF_TIM14);

TIM_TimeBaseStructure.TIM_Prescaler=psc;  //¶¨ê±Æ÷·ÖÆμ
TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; //ÏòéÏ¼ÆêyÄ￡ê½
TIM_TimeBaseStructure.TIM_Period=arr; //×Ô¶ˉÖØ×°ÔØÖμ
TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;

TIM_TimeBaseInit(TIM14,&TIM_TimeBaseStructure);//3õê¼»ˉ¶¨ê±Æ÷14

TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputNState=TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_Low;
TIM_OC1Init(TIM14,&TIM_OCInitStructure);

TIM_OC1PreloadConfig(TIM14,TIM_OCPreload_Enable);

TIM_ARRPreloadConfig(TIM14,ENABLE);

TIM_Cmd(TIM14,ENABLE);

};

编译也没有出错，但是下载后就不是呼吸灯的效果了。