PWM输出实验出现了问题请教各位大佬

YuanGEEee · 发表于 2021-9-9 23:13:12

#include "sys.h"
#include "delay.h"
#include "usart.h"
#include "led.h"
#include "key.h"

TIM_HandleTypeDef TIM3_PWM_handler;
TIM_OC_InitTypeDef TIM3_OC_init;

void TIM3_PWM_Init(void)
{
TIM3_PWM_handler.Instance=TIM3;
TIM3_PWM_handler.Init.Prescaler=90-1;
TIM3_PWM_handler.Init.CounterMode=TIM_COUNTERMODE_UP;
TIM3_PWM_handler.Init.Period=500-1; //周期

TIM3_OC_init.OCMode=TIM_OCMODE_PWM1;
TIM3_OC_init.Pulse=250; //占空比
TIM3_OC_init.OCPolarity=TIM_OCPOLARITY_LOW;

   HAL_TIM_PWM_Init(&TIM3_PWM_handler);
   HAL_TIM_PWM_ConfigChannel(&TIM3_PWM_handler,&TIM3_OC_init,TIM_CHANNEL_4);

HAL_TIM_PWM_Start(&TIM3_PWM_handler,TIM_CHANNEL_4); //使能定时器，通道

}

void SETTIM3compare4(u32 compare)
{
TIM3->CCR4=compare;
}

void HAL_TIM_PWM_MspInit(TIM_HandleTypeDef *htim) //回调函数
{
if(htim->Instance==TIM3)
{
GPIO_InitTypeDef GPIO_Initure;

   __HAL_RCC_TIM3_CLK_ENABLE(); //使能定时器时钟
   __HAL_RCC_GPIOB_CLK_ENABLE(); //使能GPIOB时钟

GPIO_Initure.Pin=GPIO_PIN_1; //PB1
GPIO_Initure.Mode=GPIO_MODE_AF_PP; //复用推挽输出
GPIO_Initure.Pull=GPIO_PULLUP; //上拉
GPIO_Initure.Speed=GPIO_SPEED_FAST; //高速
GPIO_Initure.Alternate= GPIO_AF2_TIM3; //复用为TIM3
HAL_GPIO_Init(GPIOB,&GPIO_Initure);    //初始化PB1
}
}

int main(void)
{
u8 dir=1;
u16 ledpwmvalue=0;

HAL_Init();                   //初始化HAL库
Stm32_Clock_Init(360,25,2,8); //设置时钟,180Mhz
delay_init(180);             //初始化延时函数
uart_init(115200);             //初始化USART
LED_Init();                   //初始化LED
KEY_Init();         //初始化按键

TIM3_PWM_Init();

while(1)
{
if(dir)ledpwmvalue++;
else ledpwmvalue--;

if(ledpwmvalue>300)dir=0; //改变方向
if(ledpwmvalue==0)dir=1;

SETTIM3compare4(ledpwmvalue);

}

}

为啥这代码没有实现led0由暗到亮再到暗的功能啊一直是常亮的