【无标题】大佬帮我看下stm32呼吸灯为啥不闪

#include "stm32f10x.h"
#include "Delay.h"
#include "stm32f10x_tim.h"
//#include "Encoder.h"
//#include "OLED.h"
   static u16 i=0;
   u8 Flag=1;

void TIMCH_UserConfig(u16 Period,u16 Prescaler ){
   GPIO_InitTypeDef GPIO_InitStructure;
   TIM_TimeBaseInitTypeDef TIM_InitStructure;
   TIM_OCInitTypeDef PWM_InitStructure;

   RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_AFIO,ENABLE);
   RCC_APB2PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);

   GPIO_InitStructure.GPIO_Pin=GPIO_Pin_0;
   GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;
   GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
   GPIO_Init(GPIOA,&GPIO_InitStructure);

   TIM_InitStructure.TIM_Period=Period; //重载值
   TIM_InitStructure.TIM_Prescaler=Prescaler; //预分频
   TIM_InitStructure.TIM_ClockDivision=TIM_CKD_DIV1;
TIM_InitStructure.TIM_RepetitionCounter=DISABLE;
   TIM_InitStructure.TIM_CounterMode=TIM_CounterMode_Up;
   TIM_TimeBaseInit(TIM2,&TIM_InitStructure);

   PWM_InitStructure.TIM_OCMode=TIM_OCMode_PWM1;
   PWM_InitStructure.TIM_OutputState=TIM_OutputState_Enable;
   PWM_InitStructure.TIM_OCPolarity=TIM_OCPolarity_High;
   TIM_OC1Init(TIM2,&PWM_InitStructure);

   TIM_OC1PreloadConfig(TIM2,TIM_OCPreload_Enable);
   TIM_Cmd(TIM2,ENABLE);

}
void TIMCH_PWM(void){
   if(Flag==1)
   {
       i++;
   }
   else
   {
       i--;
   }
   if(i>899)Flag=0;

   if(i==0)Flag=1;
TIM_SetCompare1(TIM2,i);

   }

     #include "stm32f10x.h"
#include "Delay.h"
#include "OLED.h"
#include "Encoder.h"
#include "timch.h"
#include "LED.h "
#include "stm32f10x_tim.h"
int16_t Num;

int main(void)
{
   SystemInit();

   TIMCH_UserConfig(899,0 );

   while (1)
   {
       TIMCH_PWM();


   }
}