TIMx_ETR外部时钟源模式2配置方法

由于stm32中的时钟源对应的GPIO口都是ST原厂已经分配好的，可以查看数据手册了解，所以我们要将外部触发信号连接到对应的时钟源GPIO pin口，这样才能起到外部时钟源的作用。

例如:TIM3_ETR外部时钟源是接在PD2口的，如果你连接其他GPIO_Pin口，此时不会进入中断函数，也就没有起到外部时钟源的作用。

Timer.c

#include "stm32f10x.h"
extern uint16_t Num;

void Timer_Init(void)
{
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD, ENABLE);
	
	//配置GPIO
	GPIO_InitTypeDef	GPIO_InitStructure;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOD,&GPIO_InitStructure);
	
	TIM_ETRClockMode2Config(TIM3, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_Inverted,0x00);
	
//	TIM_InternalClockConfig(TIM2);	//单片机上电自动默认TMI2，可不写
	TIM_TimeBaseInitTypeDef	TIM_TimeBaseInitStructure;
	TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
	TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
	TIM_TimeBaseInitStructure.TIM_Period = 10 -1;	// 0~65535
	TIM_TimeBaseInitStructure.TIM_Prescaler = 1 -1;	// 0~65535
	TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;
	TIM_TimeBaseInit(TIM3, &TIM_TimeBaseInitStructure);
	
	TIM_ClearFlag(TIM3, TIM_FLAG_Update);	//避免刚好初始化就进入中断
	TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);

	TIM_Cmd(TIM3,ENABLE);
	
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
	
	NVIC_InitTypeDef	NVIC_InitStructure;
	NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
	NVIC_Init(&NVIC_InitStructure);
	

}


uint16_t Timer_GetCounter(void)
{
	return TIM_GetCounter(TIM3);
}

void TIM2_IRQHandler(void)
{
	if(TIM_GetITStatus(TIM3, TIM_IT_Update) == SET)
	{
		Num++;
		TIM_ClearITPendingBit(TIM3, TIM_IT_Update);
	}
}

　Timer.h

#ifndef __TIMER_H
#define __TIMER_H

void Timer_Init(void);
uint16_t Timer_GetCounter(void);

#endif

main.c

#include "stm32f10x.h"
#include "Delay.h"
#include "OLED.h"
#include "Timer.h"

uint16_t Num;

int main(void)
{
	OLED_Init();
	Timer_Init();
	OLED_ShowString(1, 1, "Num:");
	OLED_ShowString(2, 1, "CNT:");

	while(1)
	{		
		OLED_ShowNum(1, 5, Num, 5);
		OLED_ShowNum(2, 5, Timer_GetCounter(), 5);
	}
}