stm32_exti（含NVIC）配置及库函数讲解

stm32的固件库中有两个非常重要的结构体，如下

/*------------------------ Nested Vectored Interrupt Controller --------------*/
typedef struct
{
vu32 ISER[2]; //对应IAR中 SETENA0 和 SETENA1
u32 RESERVED0[30];
vu32 ICER[2]; //对应IAR中 CLRENA0 和 CLRENA1
u32 RSERVED1[30];
vu32 ISPR[2]; //对应IAR中 SETPEND0 和 SETPEND1
u32 RESERVED2[30];
vu32 ICPR[2]; //对应IAR中 CLRPEND0 和 CLRPEND1
u32 RESERVED3[30];
vu32 IABR[2]; //对应IAR中 ACTIVE0 和 ACTIVE1
u32 RESERVED4[62];
vu32 IPR[15]; //对应IAR中 IP0 到 IP15
} NVIC_TypeDef;

它们对应ARM手册中的名称为
ISER=InterruptSet-EnableRegisters
ICER=InterruptClear-EnableRegisters
ISPR=InterruptSet-PendingRegister
ICPR=InterruptClear-PendingRegister
IABR=ActiveBitRegister
IPR=InterruptPriorityRegisters

typedef struct
{
vuc32 CPUID; //对应IAR中 CPUIDBR
vu32 ICSR; //对应IAR中 ICSR
vu32 VTOR; //对应IAR中 VTOR
vu32 AIRCR; //对应IAR中 AIRCR
vu32 SCR; //对应IAR中 SCR
vu32 CCR; //对应IAR中 CCR
vu32 SHPR[3]; //对应IAR中 SHPR0~SHPR2
vu32 SHCSR; //对应IAR中 SHCSR
vu32 CFSR; //对应IAR中 CFSR
vu32 HFSR; //对应IAR中 HFSR
vu32 DFSR; //对应IAR中 DFSR
vu32 MMFAR; //对应IAR中 MMFAR
vu32 BFAR; //对应IAR中 BFAR
vu32 AFSR; //对应IAR中
} SCB_TypeDef;

它们对应ARM手册中的名称为

CPUID=CPUIDBaseRegister
ICSR=InterruptControlStateRegister
VTOR=VectorTableOffsetRegister
AIRCR=ApplicationInterrupt/ResetControlRegister
SCR=SystemControlRegister
CCR=ConfigurationControlRegister
SHPR=SystemHandlersPriorityRegister
SHCSR=SystemHandlerControlandStateRegister
CFSR=ConfigurableFaultStatusRegisters
HFSR=HardFaultStatusRegister
DFSR=DebugFaultStatusRegister
MMFAR=MemManageAddressRegister
BFAR=BusFaultAddressRegister
AFSR=AuxiliaryFaultStatusRegister

UserButton硬件连接如下图所示：当按键被按下，PB9检测到低电平，相反PB9被3.3V电源拉高。

本实验要实现的功能是：按User键，用中断的方式点亮LED1。

预备知识：80个通用I/O端口以下图的方式连接到19个外部中断/事件线上：

void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;

#ifdef VECT_TAB_RAM
/* Set the Vector Table base location at 0x20000000 */
NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);
#else /* VECT_TAB_FLASH */
/* Set the Vector Table base location at 0x08000000 */
NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);
#endif

/* Configure one bit for preemption priority */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

/* Enable the EXTI9_5 Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQChannel;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}

该函数完成两个功能

1.决定将程序下载到RAM中还是FLASH中

2.配置中断分组。（NVIC中断分组只能设置一次）

3.选择中断通道号，抢占式优先级和响应优先级，使能中断

第三步：配置GPIO的模式。输入模式还是输出模式。点亮LED已讲过。

void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;

/* Configure PC.06 as Output push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_Init(GPIOC, &GPIO_InitStructure);

/* Configure PB.09 as input floating (EXTI Line 9) */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; //输入悬空模式
GPIO_Init(GPIOB, &GPIO_InitStructure);
}

第四步：外部中断线配置，本章重点！

void EXTI_Configuration(void)
{
EXTI_InitTypeDef EXTI_InitStructure;

/* Connect EXTI Line9 to PB.09 */
GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource9);

/* Configure EXTI Line9 to generate an interrupt on falling edge */
EXTI_InitStructure.EXTI_Line = EXTI_Line9;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling; //下降沿触发
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);
}

该函数完成两个功能

1.将PB9管脚用作外部中断

2.选择中断线，中断模式（中断还是事件），触发模式（电平还是跳变沿），使能

exti.c文件完整代码如下：

/* Includes ------------------------------------------------------------------*/
#include "stm32f10x_lib.h"

/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);
void NVIC_Configuration(void);
void GPIO_Configuration(void);
void EXTI_Configuration(void);
void Delay(vu32 nCount);

/*******************************************************************************
* Function Name : main
* Description : Main program.
* Input : None
* Return : None
*******************************************************************************/
int main(void)
{
#ifdef DEBUG
debug();
#endif

/* Configure the system clocks */
RCC_Configuration();

/* NVIC Configuration */
NVIC_Configuration();

/* Configure the GPIO ports */
GPIO_Configuration();

/* Configure the EXTILine */
EXTI_Configuration();

/* Generate software interrupt: simulate a falling edge applied on EXTI line 9 */
EXTI_GenerateSWInterrupt(EXTI_Line9); //只能产生一次

/* Infinite loop */
while (1)
{
}
}

/*******************************************************************************
* Function Name : RCC_Configuration
* Description : Configures the different system clocks.
* Input : None
* Return : None
*******************************************************************************/
void RCC_Configuration(void)
{
ErrorStatus HSEStartUpStatus;

/* RCC system reset(for debug purpose) */
RCC_DeInit();

/* Enable HSE */
RCC_HSEConfig(RCC_HSE_ON);

/* Wait till HSE is ready */
HSEStartUpStatus = RCC_WaitForHSEStartUp();

if (HSEStartUpStatus == SUCCESS)
{
/* Enable Prefetch Buffer */
FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);

/* Flash 2 wait state */
FLASH_SetLatency(FLASH_Latency_2);

/* HCLK = SYSCLK */
RCC_HCLKConfig(RCC_SYSCLK_Div1);

/* PCLK2 = HCLK */
RCC_PCLK2Config(RCC_HCLK_Div1);

/* PCLK1 = HCLK/2 */
RCC_PCLK1Config(RCC_HCLK_Div2);

/* PLLCLK = 8MHz * 9 = 72 MHz */
RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);

/* Enable PLL */
RCC_PLLCmd(ENABLE);

/* Wait till PLL is ready */
while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET) {}

/* Select PLL as system clock source */
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

/* Wait till PLL is used as system clock source */
while(RCC_GetSYSCLKSource() != 0x08) {}
}

/* Enable GPIOC and GPIOB clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);

/* Enable AFIO clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
}

/*******************************************************************************
* Function Name : NVIC_Configuration
* Description : Configures Vector Table base location.
* Input : None
* Return : None
*******************************************************************************/
void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;

#ifdef VECT_TAB_RAM
/* Set the Vector Table base location at 0x20000000 */
NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);
#else /* VECT_TAB_FLASH */
/* Set the Vector Table base location at 0x08000000 */
NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);
#endif

/* Configure one bit for preemption priority */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

/* Enable the EXTI9_5 Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQChannel;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}

/*******************************************************************************
* Function Name : GPIO_Configuration
* Description : Configures the different GPIO ports.
* Input : None
* Return : None
*******************************************************************************/
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;

/* Configure PC.06 as Output push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_Init(GPIOC, &GPIO_InitStructure);

/* Configure PB.09 as input floating (EXTI Line 9) */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; //输入悬空模式
GPIO_Init(GPIOB, &GPIO_InitStructure);
}

/*******************************************************************************
* Function Name : EXTI_Configuration
* Description : Configures the EXTILine.
* Input : None
* Return : None
*******************************************************************************/
void EXTI_Configuration(void)
{
EXTI_InitTypeDef EXTI_InitStructure;

/* Connect EXTI Line9 to PB.09 */
GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource9);

/* Configure EXTI Line9 to generate an interrupt on falling edge */
EXTI_InitStructure.EXTI_Line = EXTI_Line9;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling; //下降沿触发
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);
}

/*******************************************************************************
* Function Name : Delay
* Description : Inserts a delay time.
* Input : nCount: specifies the delay time length.
* Return : None
*******************************************************************************/
void Delay(vu32 nCount)
{
for(; nCount != 0; nCount--);
}

#ifdef DEBUG
/*******************************************************************************
* Function Name : assert_failed
* Description : Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* Input : - file: pointer to the source file name
* - line: assert_param error line source number
* Return : None
*******************************************************************************/
void assert_failed(u8* file, u32 line)
{
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %drn", file, line) */

/* Infinite loop */
while (1)
{
}
}
#endif