STM32:定时器外部中断

#include "stm32f10x.h"                  // Device header
#include "Delay.h"
#include "OLED.h"
#include "Timer.h"
uint16_t Num;
int main(void)
{
    OLED_Init();    
    OLED_ShowString(1,1,"Num:");
    OLED_ShowString(2,1,"CNT:");
    Timer_Init();
    while(1)
    {
        OLED_ShowNum(1,5,Num,4);
        OLED_ShowNum(2,5,Timer_GetCounter(),4);
    }
}
void TIM2_IRQHandler(void)
{
    if(TIM_GetITStatus(TIM2,TIM_IT_Update)==SET)
    {
        Num++;
        TIM_ClearITPendingBit(TIM2,TIM_IT_Update);
    }
}

#include "stm32f10x.h"                  // Device header
void Timer_Init(void)
{
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);
    GPIO_InitTypeDef GPIO_InitStruct;
    GPIO_InitStruct.GPIO_Mode=GPIO_Mode_IPU;
    GPIO_InitStruct.GPIO_Pin=GPIO_Pin_0;
    GPIO_InitStruct.GPIO_Speed=GPIO_Speed_50MHz;
    GPIO_Init(GPIOA,&GPIO_InitStruct);
    TIM_ETRClockMode2Config(TIM2,TIM_ExtTRGPSC_OFF,TIM_ExtTRGPolarity_NonInverted,0x00);
    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
    TIM_TimeBaseInitStruct.TIM_ClockDivision=TIM_CKD_DIV1;
    TIM_TimeBaseInitStruct.TIM_CounterMode=TIM_CounterMode_Up;
    TIM_TimeBaseInitStruct.TIM_Period=10-1;
    TIM_TimeBaseInitStruct.TIM_Prescaler=1-1;
    TIM_TimeBaseInitStruct.TIM_RepetitionCounter=0;
    TIM_TimeBaseInit(TIM2,&TIM_TimeBaseInitStruct);
    TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE);
    NVIC_InitTypeDef NVIC_InitStruct;
    NVIC_InitStruct.NVIC_IRQChannel=TIM2_IRQn;
    NVIC_InitStruct.NVIC_IRQChannelCmd=ENABLE;
    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority=2;
    NVIC_InitStruct.NVIC_IRQChannelSubPriority=1;
    NVIC_Init(&NVIC_InitStruct);
    TIM_Cmd(TIM2,ENABLE);
}
uint16_t Timer_GetCounter(void)
{
    return TIM_GetCounter(TIM2);
}

#ifndef  __TIMER_H
#define  __TIMER_H
void Timer_Init(void);
uint16_t Timer_GetCounter(void);
#endif