用开发板提供的PWM例程修改的TIM3 PWM无输出，TIM1就可以
/********************************** (C) COPYRIGHT *******************************
* File Name : main.c
* Author : WCH
* Version : V1.0.0
* Date : 2020/04/30
* Description : Main program body.
*******************************************************************************/
/*
*@Note
PWM输出例程：
TIM1_CH1(PA8)
本例程演示 TIM_CH1(PA8) 引脚在 PWM模式1和PWM模式2 下，输出 PWM。
*/
#include "debug.h"
/* PWM Output Mode Definition */
#define PWM_MODE1 0
#define PWM_MODE2 1
/* PWM Output Mode Selection */
//#define PWM_MODE PWM_MODE1
#define PWM_MODE PWM_MODE2
/*******************************************************************************
* Function Name : TIM1_PWMOut_Init
* Description : Initializes TIM1 PWM output.
* Input : arr: the period value.
* psc: the prescaler value.
* ccp: the pulse value.
* Return : None
*******************************************************************************/
void TIM1_PWMOut_Init( u16 arr, u16 psc, u16 ccp )
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOA | RCC_APB2Periph_TIM1, ENABLE );
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8|GPIO_Pin_11;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init( GPIOA, &GPIO_InitStructure );
TIM_TimeBaseInitStructure.TIM_Period = arr;
TIM_TimeBaseInitStructure.TIM_Prescaler = psc;
TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit( TIM1, &TIM_TimeBaseInitStructure);
#if (PWM_MODE == PWM_MODE1)
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
#elif (PWM_MODE == PWM_MODE2)
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
#endif
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = ccp;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OC1Init( TIM1, &TIM_OCInitStructure );
TIM_OC4Init(TIM1,&TIM_OCInitStructure);
TIM_CtrlPWMOutputs(TIM1, ENABLE );
TIM_OC1PreloadConfig( TIM1, TIM_OCPreload_Enable );
TIM_OC4PreloadConfig( TIM1, TIM_OCPreload_Enable );
TIM_ARRPreloadConfig( TIM1, ENABLE );
TIM_Cmd( TIM1, ENABLE );
}
void TIM3_PWMOut_Init( u16 arr, u16 psc, u16 ccp )
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
TIM_InternalClockConfig(TIM3); //选择时钟为内部时钟
RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOA|RCC_APB2Periph_GPIOB|RCC_APB1Periph_TIM3, ENABLE );
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6|GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init( GPIOA, &GPIO_InitStructure );
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1;
GPIO_Init( GPIOB, &GPIO_InitStructure );
TIM_TimeBaseInitStructure.TIM_Period = arr;
TIM_TimeBaseInitStructure.TIM_Prescaler = psc;
TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit( TIM3, &TIM_TimeBaseInitStructure);
#if (PWM_MODE == PWM_MODE1)
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
#elif (PWM_MODE == PWM_MODE2)
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
#endif
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = ccp;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OC1Init( TIM3, &TIM_OCInitStructure );
TIM_OC2Init(TIM3,&TIM_OCInitStructure);
TIM_OC3Init(TIM3,&TIM_OCInitStructure);
TIM_OC4Init(TIM3,&TIM_OCInitStructure);
TIM_CtrlPWMOutputs(TIM3, ENABLE );
TIM_OC1PreloadConfig( TIM3, TIM_OCPreload_Enable );
TIM_OC2PreloadConfig( TIM3, TIM_OCPreload_Enable );
TIM_OC3PreloadConfig( TIM3, TIM_OCPreload_Enable );
TIM_OC4PreloadConfig( TIM3, TIM_OCPreload_Enable );
//TIM_ARRPreloadConfig( TIM3, ENABLE );
TIM_Cmd( TIM3, ENABLE );
}
/*******************************************************************************
* Function Name : main
* Description : Main program.
* Input : None
* Return : None
*******************************************************************************/
int main(void)
{
u16 pwmval=0;
u8 a=1;
Delay_Init();
USART_Printf_Init(115200);
printf("SystemClk:%d\r\n",SystemCoreClock);
TIM1_PWMOut_Init( 899, 0, 1000 );
TIM3_PWMOut_Init( 899, 0, 500 );
while(1)
{
Delay_Ms(1);
if(a) pwmval++;
else pwmval--;
if(pwmval >500) a =0;
if(pwmval==0) a =1;
TIM_SetCompare1(TIM1, pwmval);
TIM_SetCompare4(TIM1, pwmval);
TIM_SetCompare1(TIM3, pwmval);
TIM_SetCompare2(TIM3, pwmval);
TIM_SetCompare3(TIM3, pwmval);
TIM_SetCompare4(TIM3, pwmval);
}
}
就是这里的问题，修改后解决了，谢谢谢大佬，祝您新年快乐，虎年大吉！