中断之外部中断
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STM32F103CB共有43个外部中断和16个内部中断。
本文引用地址：https://www.eepw.com.cn/article/201611/318391.htm具有相同数值编号的IO口被分配为同一组，共用一条中断请求线，如下图：
所以共有15条中断线，另外
●EXTI线16连接到PVD输出
●EXTI线17连接到RTC闹钟事件
●EXTI线18连接到USB唤醒事件
寄存器：1、外部中断配置寄存器AFIO_EXTxCR1->用于选择输入中断源Pin 0..3
AFIO_EXTxCR2->用于选择输入中断源Pin 0..7
AFIO_EXTxCR2->用于选择输入中断源Pin 8..11
AFIO_EXTxCR2->用于选择输入中断源Pin 12..15
(说明：5个端口PORTA..E，每个端口各有16位可供选择)
2、中断屏蔽寄存器EXTI_IMR-->屏蔽线上的中断请求共19路
3、事件屏蔽寄存器EXTI_EMR-->屏蔽线上的事件共19路
4、上升沿触发选择寄存器EXTI_RTSR->设置相应线为上升沿触发19位
5、下降沿触发选择寄存器EXTI_FTSR->设置相应线为上升沿触发19位
6、挂起寄存器EXTI_PR>中断线上发生了选择的边沿事件时置119位
7、软件中断事件寄存器EXTI_SWIER>写该位可以将EXTI_PR中相应的位值高，如果EXTI_IMR或EXTI_EMR使能，则可以产生相应的中断
配置流程：中断在使用前必须对中断线进行配置并激活
1、配置相应的IO口为输入，浮空输入时一定要加上拉或者是下拉
2、开启IO口复用时钟，设置IO与中断线的映射关系->AFIO_EXTxCR1
3、设置相应中断触发条件->EXTI_IMR、EXTI_RTSR、EXTI_FTSR
4、在NVIC中开启并使能中断，对中断分组进行配置
5、编写中断服务函数
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编写中断程序的步骤：（库函数版）
1.初始化系统时钟和端口时钟，在此需注意设置完端口时钟外还须将端口设置为功能复用IO时钟。RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE)
2.初始化GPIO。
3.中断配置，包括两部分（两个函数），中断配置和中断优先级配置。
中断配置：结构体：EXTI_InitTypeDef 。清空中断线、中断线映射CPU、中断线选择、中断模式、触发方式、使能。
优先级配置：结构体：NVIC_InitTypeDef。选组、选择IRQ通道、设置抢占优先级、设置从优先级、使能。
EG: EXTI_Configuration() 和 NVIC_Configuration()
分组情况：
| 优先级组别 | 抢占式优先级 | 副优先级 |
| 4 | 4位/16级 | 0位/0级 |
| 3 | 3位/8级 | 1位/2级 |
| 2 | 2位/4级 | 2位/4级 |
| 1 | 1位/2级 | 3位/8级 |
| 0 | 0位/0级 | 4位/6级 |
4.中断服务程序。比如0号中断线对应函数 void EXTI0_IRQHandler(void)
示例：按键改变LED的状态
1.主要功能是按键响应中断从而改变LED的状态。
2.按键所属端口：GPIOB，LED所属端口：GPIOB
3.按键管脚：PB0~PB7
4.LED管脚：PB8~PB15
5.PB0~PB5分别依次控制PB8~PB13
1 #include "pbdata.h"2 #include "led.h"3 #include "key.h"4 #include "misc.h"5 #include "stm32f10x_exti.h"6 7 void RCC_Configration(void)8 {9 SystemInit();10 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);11 RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE); //功能复用IO时钟12 }13 14 void GPIO_Configration(void)15 {16 GPIO_LED_Configration();17 GPIO_KEY_Configration();18 }19 20 /*21 *中断配置*22 */23 void EXTI_Configuration(void)24 {25 EXTI_InitTypeDef EXTI_InitStructure;26 27 EXTI_ClearITPendingBit(EXTI_Line0); //清空中断线28 EXTI_ClearITPendingBit(EXTI_Line1);29 EXTI_ClearITPendingBit(EXTI_Line2);30 EXTI_ClearITPendingBit(EXTI_Line3);31 EXTI_ClearITPendingBit(EXTI_Line4);32 EXTI_ClearITPendingBit(EXTI_Line5);33 EXTI_ClearITPendingBit(EXTI_Line6);34 EXTI_ClearITPendingBit(EXTI_Line7);35 36 GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource0);//映射37 GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource1);38 GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource2);39 GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource3);40 GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource4);41 GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource5);42 GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource6);43 GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource7);44 45 EXTI_InitStructure.EXTI_Line=EXTI_Line0 EXTI_Line1 EXTI_Line2 EXTI_Line3 EXTI_Line4 EXTI_Line5 EXTI_Line6 EXTI_Line7; //选择中断线46 47 EXTI_InitStructure.EXTI_Mode=EXTI_Mode_Interrupt; //设置模式48 EXTI_InitStructure.EXTI_Trigger=EXTI_Trigger_Falling; //设置触发方式49 EXTI_InitStructure.EXTI_LineCmd=ENABLE; //使能50 51 EXTI_Init(&EXTI_InitStructure);52 }53 54 void NVIC_Configuration0(void) //优先级设置函数55 {56 NVIC_InitTypeDef NVIC_InitStructure; 57 58 NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3); 59 60 NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn; //选择IRQ通道61 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; //抢占优先级设置62 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; //次优先级设置63 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 64 NVIC_Init(&NVIC_InitStructure); 65 }66 67 void NVIC_Configuration1(void) 68 {69 NVIC_InitTypeDef NVIC_InitStructure; 70 71 // NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3); 72 73 NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn; 74 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; 75 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; 76 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 77 NVIC_Init(&NVIC_InitStructure); 78 }79 80 void NVIC_Configuration2(void)81 {82 NVIC_InitTypeDef NVIC_InitStructure; 83 84 // NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3); 85 86 NVIC_InitStructure.NVIC_IRQChannel = EXTI2_IRQn; 87 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; 88 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; 89 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 90 NVIC_Init(&NVIC_InitStructure); 91 }92 93 void NVIC_Configuration3(void)94 {95 NVIC_InitTypeDef NVIC_InitStructure; 96 97 // NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3); 98 99 NVIC_InitStructure.NVIC_IRQChannel = EXTI3_IRQn; 100 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3; 101 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; 102 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 103 NVIC_Init(&NVIC_InitStructure); 104 }105 106 void NVIC_Configuration4(void)107 {108 NVIC_InitTypeDef NVIC_InitStructure; 109 110 // NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3); 112 NVIC_InitStructure.NVIC_IRQChannel = EXTI4_IRQn; 113 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 4; 114 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; 115 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 116 NVIC_Init(&NVIC_InitStructure); 117 }118 119 void NVIC_Configuration5(void)120 {121 NVIC_InitTypeDef NVIC_InitStructure; 122 123 // NVIC_PriorityGroupConfig(NVIC_PriorityGroup_3); 124 125 NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQn; 126 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 5; 127 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; 128 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 129 NVIC_Init(&NVIC_InitStructure); 130 }131 132 int main(void)133 {134 RCC_Configration();135 GPIO_Configration();136 EXTI_Configuration();137 NVIC_Configuration0();138 NVIC_Configuration1();139 NVIC_Configuration2();140 NVIC_Configuration3();141 NVIC_Configuration4();142 NVIC_Configuration5();143 while(1);144 }
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