外部中斷EXTI
阿新 • • 發佈：2019-01-30
前置技能:
一，STM32中斷介紹
相比簡單的51微控制器,STM32的每個IO口都可以作為外部中斷輸入
STM32中斷控制器支援19個外部中斷/事件請求:
線0-15:外部IO口輸入中斷
線16:連線到PVD輸出
線17:連線到RTC鬧鐘事件
線18:連線到USB喚醒事件
每個外部中斷線可配置獨立的觸發方式,觸發/遮蔽.專用狀態位
三種中斷觸發方式:
上升沿觸發
下降沿觸發
雙邊沿觸發
二，STM32外部中斷對映
STM32F103ZET6共112引腳,線0-15為外部IO口輸入中斷
對映關係: GPIOx.0對映EXTI0 GPIOx.1對映EXTI1 ... GPIOx.15對映EXTI15
理論上所有IO口都可以作為中斷輸入
三，中斷服務函式的分配
如圖:
中斷0,1,2,3,4單獨使用一個地址(中斷向量)
中斷5-9共用一箇中斷向量
中斷10-15共用一箇中斷向量
EXTI0_IRQHandler
EXTI1_IRQHandler
EXTI2_IRQHandler
EXTI3_IRQHandler
EXTI4_IRQHandler
EXTI9_5_IRQHandler
EXTI15_10_IRQHandler
四，外部中斷常用庫函式
// 設定IO口與中斷線的對映關係
void GPIO_EXTILineConfig(uint8_t GPIO_PortSource, uint8_t GPIO_PinSource) 四，中斷相關函式分析
stm32f10x_exit.h標頭檔案中找到EXTI_Init函式宣告:
void EXTI_Init(EXTI_InitTypeDef* EXTI_InitStruct); stm32f10x_exit.h標頭檔案中找到EXTI_InitTypeDef結構體定義
/**
* @brief EXTI Init Structure definition
*/
typedef struct
{
uint32_t EXTI_Line; /*!< Specifies the EXTI lines to be enabled or disabled.
This parameter can be any combination of @ref EXTI_Lines */
//指定要配置的中斷線
EXTIMode_TypeDef EXTI_Mode; /*!< Specifies the mode for the EXTI lines.
This parameter can be a value of @ref EXTIMode_TypeDef */
//模式：事件 OR中斷
EXTITrigger_TypeDef EXTI_Trigger; /*!< Specifies the trigger signal active edge for the EXTI lines.
This parameter can be a value of @ref EXTIMode_TypeDef */
//觸發方式：上升沿/下降沿/雙沿觸發
FunctionalState EXTI_LineCmd; /*!< Specifies the new state of the selected EXTI lines.
This parameter can be set either to ENABLE or DISABLE */
//使能 OR失能
}EXTI_InitTypeDef;mode屬性有效性校驗IS_EXTI_MODE
/**
* @brief EXTI mode enumeration
*/
typedef enum
{
EXTI_Mode_Interrupt = 0x00, //中斷
EXTI_Mode_Event = 0x04 //事件
}EXTIMode_TypeDef;
#define IS_EXTI_MODE(MODE) (((MODE) == EXTI_Mode_Interrupt) || ((MODE) == EXTI_Mode_Event))EXTI_Trigger屬性有效性校驗IS_EXTI_TRIGGER
/**
* @brief EXTI Trigger enumeration
*/
typedef enum
{
EXTI_Trigger_Rising = 0x08, //上升沿
EXTI_Trigger_Falling = 0x0C, //下降沿
EXTI_Trigger_Rising_Falling = 0x10 //雙邊沿
}EXTITrigger_TypeDef;
#define IS_EXTI_TRIGGER(TRIGGER) (((TRIGGER) == EXTI_Trigger_Rising) || \
((TRIGGER) == EXTI_Trigger_Falling) || \
((TRIGGER) == EXTI_Trigger_Rising_Falling))配置例項:
EXTI_InitStructure.EXTI_Line=EXTI_Line2;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);stm32f10x_gpio.c檔案中找到GPIO_EXTILineConfig函式原始碼:
/**
* @brief Selects the GPIO pin used as EXTI Line.
* @param GPIO_PortSource: selects the GPIO port to be used as source for EXTI lines.
* This parameter can be GPIO_PortSourceGPIOx where x can be (A..G).
* @param GPIO_PinSource: specifies the EXTI line to be configured.
* This parameter can be GPIO_PinSourcex where x can be (0..15).
* @retval None
*/
void GPIO_EXTILineConfig(uint8_t GPIO_PortSource, uint8_t GPIO_PinSource)
{
uint32_t tmp = 0x00;
/* Check the parameters */
assert_param(IS_GPIO_EXTI_PORT_SOURCE(GPIO_PortSource));
assert_param(IS_GPIO_PIN_SOURCE(GPIO_PinSource));
tmp = ((uint32_t)0x0F) << (0x04 * (GPIO_PinSource & (uint8_t)0x03));
AFIO->EXTICR[GPIO_PinSource >> 0x02] &= ~tmp;
AFIO->EXTICR[GPIO_PinSource >> 0x02] |= (((uint32_t)GPIO_PortSource) << (0x04 * (GPIO_PinSource & (uint8_t)0x03)));
}GPIO_PortSource引數有效性驗證 IS_GPIO_EXTI_PORT_SOURCE:
/** @defgroup GPIO_Port_Sources
* @{
*/
#define GPIO_PortSourceGPIOA ((uint8_t)0x00)
#define GPIO_PortSourceGPIOB ((uint8_t)0x01)
#define GPIO_PortSourceGPIOC ((uint8_t)0x02)
#define GPIO_PortSourceGPIOD ((uint8_t)0x03)
#define GPIO_PortSourceGPIOE ((uint8_t)0x04)
#define GPIO_PortSourceGPIOF ((uint8_t)0x05)
#define GPIO_PortSourceGPIOG ((uint8_t)0x06)
#define IS_GPIO_EXTI_PORT_SOURCE(PORTSOURCE) (((PORTSOURCE) == GPIO_PortSourceGPIOA) || \
((PORTSOURCE) == GPIO_PortSourceGPIOB) || \
((PORTSOURCE) == GPIO_PortSourceGPIOC) || \
((PORTSOURCE) == GPIO_PortSourceGPIOD) || \
((PORTSOURCE) == GPIO_PortSourceGPIOE) || \
((PORTSOURCE) == GPIO_PortSourceGPIOF) || \
((PORTSOURCE) == GPIO_PortSourceGPIOG))GPIO_PinSource引數有效性驗證IS_GPIO_PIN_SOURCE:
/** @defgroup GPIO_Pin_sources
* @{
*/
#define GPIO_PinSource0 ((uint8_t)0x00)
#define GPIO_PinSource1 ((uint8_t)0x01)
#define GPIO_PinSource2 ((uint8_t)0x02)
#define GPIO_PinSource3 ((uint8_t)0x03)
#define GPIO_PinSource4 ((uint8_t)0x04)
#define GPIO_PinSource5 ((uint8_t)0x05)
#define GPIO_PinSource6 ((uint8_t)0x06)
#define GPIO_PinSource7 ((uint8_t)0x07)
#define GPIO_PinSource8 ((uint8_t)0x08)
#define GPIO_PinSource9 ((uint8_t)0x09)
#define GPIO_PinSource10 ((uint8_t)0x0A)
#define GPIO_PinSource11 ((uint8_t)0x0B)
#define GPIO_PinSource12 ((uint8_t)0x0C)
#define GPIO_PinSource13 ((uint8_t)0x0D)
#define GPIO_PinSource14 ((uint8_t)0x0E)
#define GPIO_PinSource15 ((uint8_t)0x0F)
#define IS_GPIO_PIN_SOURCE(PINSOURCE) (((PINSOURCE) == GPIO_PinSource0) || \
((PINSOURCE) == GPIO_PinSource1) || \
((PINSOURCE) == GPIO_PinSource2) || \
((PINSOURCE) == GPIO_PinSource3) || \
((PINSOURCE) == GPIO_PinSource4) || \
((PINSOURCE) == GPIO_PinSource5) || \
((PINSOURCE) == GPIO_PinSource6) || \
((PINSOURCE) == GPIO_PinSource7) || \
((PINSOURCE) == GPIO_PinSource8) || \
((PINSOURCE) == GPIO_PinSource9) || \
((PINSOURCE) == GPIO_PinSource10) || \
((PINSOURCE) == GPIO_PinSource11) || \
((PINSOURCE) == GPIO_PinSource12) || \
((PINSOURCE) == GPIO_PinSource13) || \
((PINSOURCE) == GPIO_PinSource14) || \
((PINSOURCE) == GPIO_PinSource15))五，外部中斷的配置步驟
1,初始化IO口為輸入。
GPIO_Init();
2,開啟IO口複用時鐘。
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);
3,設定IO口與中斷線的對映關係。
void GPIO_EXTILineConfig();
4,初始化線上中斷，設定觸發條件等。
EXTI_Init();
5,配置中斷分組（NVIC），並使能中斷。
NVIC_Init();
6,編寫中斷服務函式。
EXTIx_IRQHandler();
7,清除中斷標誌位
EXTI_ClearITPendingBit();六，硬體連線
使用按鍵觸發外部中斷
KEY0 KEY1 KEY2接低電平,所以設定IO口PE2,PE3,E4為上拉輸入
按鍵按下時, IO口輸入低電平,檢測下降沿即可判斷按鍵按下
相反,WK_UP連線VCC,需設定IO口PA0為下拉輸入
按鍵按下時,IO口輸入高電平,檢測上升沿即可判斷按鍵按下
七，外部中斷程式碼
HARDWARE/EXIT資料夾,新建exit.h檔案
#ifndef __EXTI_H
#define __EXIT_H
#include "sys.h"
void EXTIX_Init(void); // 外部中斷初始化
#endif新增標頭檔案到工程配置
HARDWARE/EXIT資料夾,新建exit.c檔案實現EXTIX_Init(void)外部中斷初始化函式
#include "exti.h"
#include "led.h"
#include "key.h” // 按鍵埠初始化
#include "delay.h"
#include "usart.h"
#include "beep.h"
void EXTIX_Init(void)
{
EXTI_InitTypeDef EXTI_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
// 1,按鍵埠初始化 - 初始化IO口為輸入(詳細參考按鍵部分)
KEY_Init();
// 使能AFIO複用時鐘
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);
// 配置中斷線對映-GPIOE.2對映到中斷線2-按鍵KEY2
GPIO_EXTILineConfig(GPIO_PortSourceGPIOE,GPIO_PinSource2);
//初始化外部中斷-線2
EXTI_InitStructure.EXTI_Line=EXTI_Line2; // 中斷線
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt; // 中斷OR事件
// 觸發方式-下降沿觸發(因為連線GND)
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE; // 使能
EXTI_Init(&EXTI_InitStructure);
// 配置中斷線對映-GPIOE.3 對映到中斷線3-按鍵KEY1
GPIO_EXTILineConfig(GPIO_PortSourceGPIOE,GPIO_PinSource3);
// 初始化外部中斷-線3
EXTI_InitStructure.EXTI_Line=EXTI_Line3;
EXTI_Init(&EXTI_InitStructure);
// 配置中斷線對映-GPIOE.4 對映到中斷線4-按鍵KEY0
GPIO_EXTILineConfig(GPIO_PortSourceGPIOE,GPIO_PinSource4);
//初始化外部中斷-線4
EXTI_InitStructure.EXTI_Line=EXTI_Line4;
EXTI_Init(&EXTI_InitStructure);
// 配置中斷線對映-GPIOA.0對映到中斷線0-按鍵WK_UP
GPIO_EXTILineConfig(GPIO_PortSourceGPIOA,GPIO_PinSource0);
// 初始化外部中斷-線0
EXTI_InitStructure.EXTI_Line=EXTI_Line0;
// 觸發方式-上升沿觸發(因為連線VCC)
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;
EXTI_Init(&EXTI_InitStructure);
// 中斷優先順序配置
NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn; // 通道0
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02; // 搶佔優先順序
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x03; // 響應優先順序
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; // 使能
NVIC_Init(&NVIC_InitStructure);
NVIC_InitStructure.NVIC_IRQChannel = EXTI2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
NVIC_InitStructure.NVIC_IRQChannel = EXTI3_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
NVIC_InitStructure.NVIC_IRQChannel = EXTI4_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x00;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
//線0中斷函式
void EXTI0_IRQHandler(void)
{
delay_ms(10); // 延時防止按鍵抖動
if(WK_UP==1) // 等待跳過抖動後再次判斷是否按下
{
BEEP=!BEEP; // 蜂鳴器取反
}
EXTI_ClearITPendingBit(EXTI_Line0); // 手動清除中斷標誌-線1
}
//線2中斷函式
void EXTI2_IRQHandler(void)
{
delay_ms(10);
if(KEY2==0)
{
LED0=!LED0; // LED0取反
}
EXTI_ClearITPendingBit(EXTI_Line2);
}
//線3中斷函式
void EXTI3_IRQHandler(void)
{
delay_ms(10);
if(KEY1==0)
{
LED1=!LED1; // LED1取反
}
EXTI_ClearITPendingBit(EXTI_Line3);
}
//線4中斷函式
void EXTI4_IRQHandler(void)
{
delay_ms(10);
if(KEY0==0)
{
LED0=!LED0; // LED0取反
LED1=!LED1; // LED1取反
}
EXTI_ClearITPendingBit(EXTI_Line4);
}USER資料夾新建main.c檔案,編寫主函式
#include "led.h"
#include "delay.h"
#include "key.h"
#include "sys.h"
#include "usart.h"
#include "exti.h"
#include "beep.h"
int main(void)
{
delay_init(); // 延遲初始化
//設定中斷優先順序分組2 2位搶佔2位響應
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
uart_init(115200); // 初始化串列埠 設定波特率為115200
LED_Init(); // LED埠初始化
BEEP_Init(); // 蜂鳴器埠初始化
KEY_Init(); // 按鍵埠初始化
EXTIX_Init(); // 外部中斷初始化
LED0=0; // LED0點亮
while(1)
{
printf("列印輸入\r\n");
delay_ms(1000);
}
}