求高手解答，PWM输出端口电压值一直为电源电压，没有变化

dmingshen · 发表于 2021-6-16 17:07:16

本帖最后由 dmingshen 于 2021-6-16 17:10 编辑

芯片为STM32F407ZGT6

Tim_pwm.c
#include "Tim_pwm.h"
#include "Gpio.h"
void TIM2_PWM_Init(u32 arr,u32 psc)
{

      GPIO_InitTypeDef GPIO_InitStructure;
      TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
      TIM_OCInitTypeDef  TIM_OCInitStructure;

      RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
      RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

      GPIO_PinAFConfig(GPIOA,GPIO_PinSource1,GPIO_AF_TIM2);

      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
      GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
      GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
      GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
      GPIO_Init(GPIOA,&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(TIM2,&TIM_TimeBaseStructure)；

      TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
      TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
      TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
      TIM_OC2Init(TIM2, &TIM_OCInitStructure);

      TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Enable);

      TIM_ARRPreloadConfig(TIM2,ENABLE);

      TIM_Cmd(TIM2, ENABLE);
}

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_PinAFConfig(GPIOF,GPIO_PinSource9,GPIO_AF_TIM14);

      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
      GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
      GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
      GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
      GPIO_Init(GPIOF,&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(TIM14,&TIM_TimeBaseStructure);

      TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
      TIM_OCInitStructure.TIM_OutputState = 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);
}

主函数通过TIM_SetCompare1(TIM2,led0pwmval)修改占空比，但是PA1输出的电压一直为+3.3V，不是脉冲：