我想通过串口发数据体调节PWM，这个可以实现，但是无法对PWM占空比进行初始化，

高原

预期功能：用TIM3产生PWM，并且通过串口发送数据实现PWM可调，
问题：调用了库函数TIM_SetCompare1(TIM3,CCR1_Val);后就不能对PWM进行初始化了，芯片一上电相应的PWM通道直接被拉高，初始化语句不起作用，但是通过串口发数据能调节，就是初始化无法完成，下面是代码：
//001
#include "pwm_output.h"

uint16_t CCR1_Val=500;//对PWM占空比进行初始化

void TIM3_GPIO_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;

/*GPIOA and GPIOB clock enable*/
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_GPIOB,ENABLE);

/*TIM3 clock enable*/
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE); //PLCK1¶t±¶Æμoó×÷ÎaTIM3μÄê±ÖóÔ′μèóú72MHz

/*GPIOA Configuration:TIM3 channel 1 and 2 as alternate function push-pull*/
/*TIM3 channel 1--PA6, TIM3 channel 2---PA7*/
GPIO_InitStructure.GPIO_Pin=GPIO_Pin_6|GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;         // ¸′óÃíÆíìêä3ö
GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;   

GPIO_Init(GPIOA,&GPIO_InitStructure);  //½«½á11ìåμÄ3õÖμ¸3¸øÏàó|μļÄ′æÆ÷

/*GPIOB Configuration :TIM3 channel 3 and 4 as alternate function push-pull*/
GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_0 | GPIO_Pin_1;
//        GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;         // ¸′óÃíÆíìêä3ö
//        GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;

GPIO_Init(GPIOB,&GPIO_InitStructure);

}


void TIM3_Mode_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;//ê±»ù3õê¼»ˉóé¸Ã½á11ìåμļ¸¸ö3éÔ±ÅäÖÃ

TIM_OCInitTypeDef TIM_OCInitStructure; //í¨óö¨ê±Æ÷μÄêä3öÄ￡ê½óé¸Ã½á11ìåμļ¸¸ö3éÔ±ÅäÖÃ


/*time base configuration*/
TIM_TimeBaseInitStructure.TIM_Period=999; //¶¨ê±Æ÷′ó0μ½999Îaò»¸ö¶¨ê±ÖüÆú￡¨¼′1000￡©
TIM_TimeBaseInitStructure.TIM_Prescaler=0; //éèÖÃÔ¤·ÖÆμÆ÷￡¬2»Ô¤·ÖÆμ￡¬¼′Îa72MHz
TIM_TimeBaseInitStructure.TIM_ClockDivision=TIM_CKD_DIV1; //éèÖÃê±Öó·ÖÆμÏμêy￡¬2»·ÖÆμ
TIM_TimeBaseInitStructure.TIM_CounterMode=TIM_CounterMode_Up; //ÏòéϼÆêyÄ￡ê½

/*Initializes the TIMx Time Base Unit peripheral according to the specified parameters
* in the TIM_TimeBaseInitStruct.
*/
TIM_TimeBaseInit(TIM3,&TIM_TimeBaseInitStructure);

/* PWM1 Mode configuration: Channel1 */
TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1; //ÅäÖÃÎaPWM1Ä￡ê½
TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable; //ê1Äü
TIM_OCInitStructure.TIM_Pulse=CCR1_Val;//éèÖÃìø±äÖμ￡¬μ±¼ÆêyÆ÷¼Æêyμ½Õa¸öÖμê±￡¬μçƽ·￠éúìø±ä
TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_High; //챶¨ê±Æ÷μÄÖμD¡óúCCR1_Valê±Îa¸ßμçƽ
TIM_OC1Init(TIM3,&TIM_OCInitStructure);//ê1Äüí¨μà1
TIM_OC1PreloadConfig(TIM3,TIM_OCPreload_Enable);//ê1ÄüԤװÔؼÄ′æÆ÷(CCR1)

/* PWM1 Mode configuration: Channel2 */
TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse=CCR1_Val; //éèÖÃí¨μà2μÄìø±äÖμ￡¬2úéúáíò»¸öÕ¼¿Õ±èμ&#196WM
TIM_OC2Init(TIM3,&TIM_OCInitStructure);//ê1Äüí¨μà2
TIM_OC2PreloadConfig(TIM3,TIM_OCPreload_Enable);

/* PWM1 Mode configuration: Channel3 */
TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse=CCR1_Val;
TIM_OC3Init(TIM3,&TIM_OCInitStructure);//ê1Äüí¨μà3
TIM_OC3PreloadConfig(TIM3,TIM_OCPreload_Enable);

/* PWM1Mode configuration: Channel4 */
TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse=CCR1_Val;
TIM_OC4Init(TIM3,&TIM_OCInitStructure);//ê1Äüí¨μà4
TIM_OC4PreloadConfig(TIM3,TIM_OCPreload_Enable);


TIM_ARRPreloadConfig(TIM3,ENABLE); //ê1ÄüÖØÔؼÄ′æÆ÷ARR
TIM_Cmd(TIM3,ENABLE); //ê1Äü¶¨ê±Æ÷3
}

/*
*oˉêyÃû￡oTIM3_Config
*1|Äü:TIM3 êä3&#246WMDÅoÅ3õê¼»ˉ￡¬Ö»òaμ÷óÃÕa¸öoˉêy
*     TIM3μÄËĸöí¨μà¾í»áóDPWMDÅoÅêä3ö
*êäèë: ÎT
*êä3ö￡oÎT
*μ÷óÃ￡oía2¿μ÷óÃ
*/

void TIM3_PWM_Init()
{
TIM3_GPIO_Config();
TIM3_Mode_Config();
}

void ZKB(char a0,char a1,char a2) //Mark-Space Ratio:Õ¼¿Õ±è
{
uint16_t bai,shi,ge;

bai=((uint16_t)a0)-48;
shi=((uint16_t)a1)-48;
ge=((uint16_t)a2)-48;
CCR1_Val=bai*100+shi*10+ge;  
TIM_SetCompare1(TIM3,CCR1_Val);//í¨μà1
TIM_SetCompare2(TIM3,CCR1_Val);//í¨μà2
TIM_SetCompare3(TIM3,CCR1_Val);//í¨μà3
TIM_SetCompare4(TIM3,CCR1_Val);//í¨μà4
}
//以下是串口中断
void USART1_IRQHandler(void)
{
if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)
{
/* Read one byte from the receive data register */
RxBuffer[RxCounter++] = USART_ReceiveData(USART1);//¶áêy¾Yoóó2¼t×Ô¶ˉÇå3y±ê־λ
if(RxCounter==4)
{
printf("%s\n",RxBuffer);
printf("%c\n",RxBuffer[0]);
printf("%c\n",RxBuffer[1]);
printf("%c\n",RxBuffer[2]);
printf("%c\n",RxBuffer[3]);

ZKB(RxBuffer[0],RxBuffer[1],RxBuffer[2]); //Õ¼¿Õ±è(3μËù)μ÷½ú
RxCounter=0;//

}
  
}


}
求大神指导，纠结好几天了

flyleaf

参考例程里的呼吸灯程序，呼吸灯就是使用变化的pwm波的。

引脚一直被拉高，检查下该引脚是不是在板子其它地方使用了

高原

flyleaf 发表于 2015-10-29 08:48
参考例程里的呼吸灯程序，呼吸灯就是使用变化的pwm波的。

引脚一直被拉高，检查下该引脚是不是在板子其 ...

但是我通过串口发数据可以改变PWM的占空比