系列文章目录

---

 

---

前言

本章主要是学习STM32F103系列的EXTI（Extern Interrupt）外部中断，本次实验用到的传感器用按键替代。

---

 

一、对射式红外传感器计数

        本意是传感器两边的红外线遮住一次，拿开就计数一次，我这里就直接按键按一次，计数就加一次。

1.原理图

图1.1.1 对射式红外传感器计数原理图

2.代码

CountSensor.c :  对射式红外传感器驱动函数，驱动的是如图1.1.1所示的PB14口

#include "stm32f10x.h"                  // Device header

uint16_t CountSensor_Count;

void CountSensor_Init(void)
{
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
	
	GPIO_InitTypeDef  GPIO_InitStructure;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_14;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOB, &GPIO_InitStructure);
	
	GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource14);
	
	EXTI_InitTypeDef EXTI_InitStructure;
	EXTI_InitStructure.EXTI_Line = EXTI_Line14;
	EXTI_InitStructure.EXTI_LineCmd = ENABLE;
	EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
	EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
	EXTI_Init(&EXTI_InitStructure);
	
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
	
	NVIC_InitTypeDef NVIC_InitStructure;
	NVIC_InitStructure.NVIC_IRQChannel = EXTI15_10_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
	NVIC_Init(&NVIC_InitStructure);
}

uint16_t CountSensor_Get(void)
{
	return CountSensor_Count;
}

void EXTI15_10_IRQHandler(void)
{
	if (EXTI_GetITStatus(EXTI_Line14) == SET)
	{
		CountSensor_Count++;
		EXTI_ClearITPendingBit(EXTI_Line14);
	}
}

CountSensor.h：头文件声明函数（中断函数不需要声明和调用，中断时自己会执行）（中断有对应特定的函数名在启动文件（/Start/startup_stm32f10x_md.s）里面寻找，直接复制粘贴，比较不会出错，函数名如果错了，就进不了中断）

#ifndef __COUNTSENSOR_H__
#define __COUNTSENSOR_H__

void CountSensor_Init(void);
uint16_t CountSensor_Get(void);

#endif

main.c

#include "stm32f10x.h"                  // Device header
#include "Delay.h"
#include "OLED.h"
#include "CountSensor.h"

int main(void)
{
	OLED_Init();
	CountSensor_Init();
	
	OLED_ShowString(1, 1, "Count:");
	
	while(1)
	{
		OLED_ShowNum(1, 7, CountSensor_Get(), 5);
	}
}	

3运行结果

下降沿触发中断

运行时PB14口为高电平，按下按键后变低电平，Count++

图1.3.1 执行前

图1.3.2 按键按下后

二、旋转编码器计数

1.原理图

遵循和UP主用的一样的GPIO口，GPIOB_Pin_0,GPIOB_Pin_1。

图2.1.1 旋转编码器计数

2.代码

代码如下（示例）：

Encoder.c

#include "stm32f10x.h"                  // Device header

int16_t Encoder_Count;

void Encoder_Init(void)
{
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
	
	GPIO_InitTypeDef  GPIO_InitStructure;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOB, &GPIO_InitStructure);
	
	GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource0);
	GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource1);
	
	EXTI_InitTypeDef EXTI_InitStructure;
	EXTI_InitStructure.EXTI_Line = EXTI_Line0 | EXTI_Line1;
	EXTI_InitStructure.EXTI_LineCmd = ENABLE;
	EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
	EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
	EXTI_Init(&EXTI_InitStructure);
	
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
	
	NVIC_InitTypeDef NVIC_InitStructure;
	NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
	NVIC_Init(&NVIC_InitStructure);
	
	NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
	NVIC_Init(&NVIC_InitStructure);
}

int16_t Encoder_Get(void)
{
	int16_t Temp;
	Temp = Encoder_Count;
	Encoder_Count = 0;
	return Temp;
}

void EXTI0_IRQHandler(void)
{
	if (EXTI_GetITStatus(EXTI_Line0) == SET)
	{
		if (GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_0) == 0)
		{
			Encoder_Count--;
		}
		EXTI_ClearITPendingBit(EXTI_Line0);
	}
	
}

void EXTI1_IRQHandler(void){
	if (EXTI_GetITStatus(EXTI_Line1) == SET)
	{
		if (GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_1) == 0)
		{
			Encoder_Count++;
		}
		EXTI_ClearITPendingBit(EXTI_Line1);
	}
}

        因为GPIOB_Pin_0,GPIOB_Pin_1的中断函数名不同，分别为EXTI0_IRQHandler，EXTI1_IRQHandler。所以是分开的两个中断函数。

        如果中断函数名相同的只要写一个就可以了。例如：

void EXTI15_10_IRQHandler(void)
{
	if (EXTI_GetITStatus(EXTI_Line14) == SET)
	{
		if (GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_14) == 0)
		{
			Encoder_Count--;
		}
		EXTI_ClearITPendingBit(EXTI_Line14);
	}

    if (EXTI_GetITStatus(EXTI_Line15) == SET)
	{
		if (GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_15) == 0)
		{
			Encoder_Count++;
		}
		EXTI_ClearITPendingBit(EXTI_Line15);
	}
	
}

图2.2.1 启动文件中的中断函数名参考

3.运行结果

图2.3.1 启动时

图2.3.2 按键1按下数值减1

图2.3.3 按键2按下数值加1

---

总结

仿真毕竟比不上真实硬件，硬件很多执行器，传感器都是封装好的，目前还不会PCB，在以后的文章中我会简化电路，但原理是一样的。