#include "led.h"

 void TIM3_Int_Init(u16 arr,u16 psc)

 {

     TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

     NVIC_InitTypeDef NVIC_InitStructure;

     RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //设置TIM3时钟使能

     TIM_TimeBaseStructure.TIM_Period = arr; //设置重装载寄存器的周期

     TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置时钟频率除数的预分频值

     TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //设置时钟分割

     TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //向上的计数模式

     TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //TIM3的初始化

     TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE ); //TIM3更新中断使能

     NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;  //TIM3中断

     NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = ;  //先占优先0级

     NVIC_InitStructure.NVIC_IRQChannelSubPriority = ;  //从占优先3级

     NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道使能

     NVIC_Init(&NVIC_InitStructure);  //初始化NVIC寄存器

     TIM_Cmd(TIM3, ENABLE);  //使能TIM3

 }

 //定时器3中断服务程序

 void TIM3_IRQHandler(void)   //TIM3中断

 {

     if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)  //检查TIM3更新中断发生与否

         {

         TIM_ClearITPendingBit(TIM3, TIM_IT_Update  );  //清除TIMx更新中断标志

         LED2=!LED2;  //取反

         }

 }

 #include "stm32f10x_conf.h"

 #include "led.h"

 #include "key.h"

 #include "delay.h"

 #include "timer.h"

 #include "usart.h"

 int main(void)

 {

     delay_init();

     LED_Init();

     NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

     uart_init();

     TIM3_Int_Init(,);

     //((4999+1)*( 7199+1))/72=500000us=500ms  延时500ms

   while()

   {

         LED3=!LED3;

         delay_ms();

         /*当数值为2000时，延时时间变快。当数值为1500以下，

         延时时间为x/1000，只设了几个值。其他值都还没有尝试。

         */

   }

 }