PWM输出问题 求大神帮忙。。。。。。通过定时器T2的管脚复用功能，通过输出通道4（PB11）输出PWM波形控制LED做呼吸灯，发现对应的LED无实际的现象

sccdtlm

通过定时器T2的管脚复用功能，通过输出通道4（PB11）输出PWM波形控制LED做呼吸灯，发现对应的LED无实际的现象，原程序如下：

初始化函数：
void T2_PWM_Init(u16 prer,u16 rlr)
{
TIM_OCInitTypeDef TIM_OCInitStruct; 
GPIO_InitTypeDef GPIOInitInitStruct; 
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO|RCC_APB2Periph_GPIOB,ENABLE);
GPIO_PinRemapConfig(GPIO_FullRemap_TIM2,ENABLE);

TIM_DeInit(TIM2);
TIM_TimeBaseInitStruct.TIM_CounterMode=TIM_CounterMode_Up;
TIM_TimeBaseInitStruct.TIM_ClockDivision=TIM_CKD_DIV1; 
TIM_TimeBaseInitStruct.TIM_Period=prer;
TIM_TimeBaseInitStruct.TIM_Prescaler=rlr;
TIM_TimeBaseInitStruct.TIM_RepetitionCounter=0;
TIM_TimeBaseInit(TIM2,&TIM_TimeBaseInitStruct); 

GPIOInitInitStruct.GPIO_Mode=GPIO_Mode_AF_PP;
GPIOInitInitStruct.GPIO_Pin=GPIO_Pin_11;
GPIOInitInitStruct.GPIO_Speed=GPIO_Speed_50MHz;
GPIO_Init(GPIOB,&GPIOInitInitStruct);

TIM_OCInitStruct.TIM_OCMode=TIM_OCMode_PWM2;
TIM_OCInitStruct.TIM_OutputState=TIM_OutputState_Enable;
TIM_OCInitStruct.TIM_OCNPolarity=TIM_OCPolarity_High;
TIM_OC4Init(TIM2,&TIM_OCInitStruct);

TIM_OC4PreloadConfig(TIM2,TIM_OCPreload_Enable);
TIM_Cmd(TIM2,ENABLE);
}


主函数：
int main(void)
{
u8 dir=1;
u16 LED3_PWM_Val=0;
SystemInit();
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
uart_init(115200);
printf("System START1\r\n");
delay_init();
Hal_LED_Init();
Hal_KEY_Init();
T3_Init(1);
EXIT_Init();
IDWG_Init(4,625);
T2_PWM_Init(899,0);
 while (1)
{
IWDG_ReloadCounter();
if(dir==1) LED3_PWM_Val++;
else LED3_PWM_Val--;
printf("LED3_PWM_Val %d\r\n",LED3_PWM_Val);
if (LED3_PWM_Val>300) dir=0;
if (LED3_PWM_Val==0) dir=1;

TIM_SetCompare4(TIM2,LED3_PWM_Val);
delay_ms(10);
}
}


来个大神帮忙解决下

正点原子

帮顶.....