#define SYSCFG_EXTICR2_EXTIX_SHIFT (0) #define SYSCFG_EXTICR2_EXTIX_MASK (0xFFFFU << SYSCFG_EXTICR2_EXTIX_SHIFT) #define SYSCFG_EXTICR2_EXTIX(x) (((uint32_t)(((uint32_t)(x)) << SYSCFG_EXTICR2_EXTIX_SHIFT)) & SYSCFG_EXTICR2_EXTIX_MASK)

这段代码是关于SYSCFG_EXTICR2_EXTIX的定义，它是用来配置外部中断线的选择。这个宏定义了SYSCFG_EXTICR2_EXTIX的位偏移和位掩码，并提供了一个宏函数来设置SYSCFG_EXTICR2_EXTIX的值。具体来说：

- SYSCFG_EXTICR2_EXTIX_SHIFT定义了位偏移值，它用来指定SYSCFG_EXTICR2_EXTIX的起始位。
- SYSCFG_EXTICR2_EXTIX_MASK定义了位掩码，它用来屏蔽其他位，只保留SYSCFG_EXTICR2_EXTIX的位。
- SYSCFG_EXTICR2_EXTIX(x)是一个宏函数，它将传入的参数x左移SYSCFG_EXTICR2_EXTIX_SHIFT位，并与SYSCFG_EXTICR2_EXTIX_MASK进行按位与操作，以设置SYSCFG_EXTICR2_EXTIX的值。

这些宏定义可以用于配置外部中断线的选择，通过设置SYSCFG_EXTICR2_EXTIX的值来选择相应的外部中断线。

相关问题

RCC_APB2Periph_SYSCFG在哪个头文件定义了

RCC_APB2Periph_SYSCFG位于STM32的寄存器映射表中，对应的头文件为"stm32f4xx_rcc.h"，在该头文件中可以找到如下定义：

#define RCC_APB2Periph_SYSCFG ((uint32_t)0x00004000) /*!< SYSCFG clock enable */

同时，还需要包含stm32f4xx.h头文件才能使用这个宏定义。

UCOSIII外部中断控key0 key1 key2按键代码

下面是一个UCOSIII外部中断控制key0、key1、key2按键的代码示例：

#include "stm32f4xx.h"
#include "ucos_ii.h"

#define KEY0_GPIO_PORT  GPIOA
#define KEY0_GPIO_PIN   GPIO_Pin_0
#define KEY0_EXTI_LINE  EXTI_Line0
#define KEY0_EXTI_PORT  EXTI_PortSourceGPIOA
#define KEY0_EXTI_PIN   EXTI_PinSource0
#define KEY0_EXTI_IRQ   EXTI0_IRQn

#define KEY1_GPIO_PORT  GPIOE
#define KEY1_GPIO_PIN   GPIO_Pin_2
#define KEY1_EXTI_LINE  EXTI_Line2
#define KEY1_EXTI_PORT  EXTI_PortSourceGPIOE
#define KEY1_EXTI_PIN   EXTI_PinSource2
#define KEY1_EXTI_IRQ   EXTI2_IRQn

#define KEY2_GPIO_PORT  GPIOE
#define KEY2_GPIO_PIN   GPIO_Pin_3
#define KEY2_EXTI_LINE  EXTI_Line3
#define KEY2_EXTI_PORT  EXTI_PortSourceGPIOE
#define KEY2_EXTI_PIN   EXTI_PinSource3
#define KEY2_EXTI_IRQ   EXTI3_IRQn

static OS_EVENT* key_sem;

void Key_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    EXTI_InitTypeDef EXTI_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOE, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);

    GPIO_InitStructure.GPIO_Pin = KEY0_GPIO_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(KEY0_GPIO_PORT, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = KEY1_GPIO_PIN;
    GPIO_Init(KEY1_GPIO_PORT, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = KEY2_GPIO_PIN;
    GPIO_Init(KEY2_GPIO_PORT, &GPIO_InitStructure);

    SYSCFG_EXTILineConfig(KEY0_EXTI_PORT, KEY0_EXTI_PIN);
    SYSCFG_EXTILineConfig(KEY1_EXTI_PORT, KEY1_EXTI_PIN);
    SYSCFG_EXTILineConfig(KEY2_EXTI_PORT, KEY2_EXTI_PIN);

    EXTI_InitStructure.EXTI_Line = KEY0_EXTI_LINE;
    EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
    EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
    EXTI_InitStructure.EXTI_LineCmd = ENABLE;
    EXTI_Init(&EXTI_InitStructure);

    EXTI_InitStructure.EXTI_Line = KEY1_EXTI_LINE;
    EXTI_Init(&EXTI_InitStructure);

    EXTI_InitStructure.EXTI_Line = KEY2_EXTI_LINE;
    EXTI_Init(&EXTI_InitStructure);

    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0f;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0f;

    NVIC_InitStructure.NVIC_IRQChannel = KEY0_EXTI_IRQ;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    NVIC_InitStructure.NVIC_IRQChannel = KEY1_EXTI_IRQ;
    NVIC_Init(&NVIC_InitStructure);

    NVIC_InitStructure.NVIC_IRQChannel = KEY2_EXTI_IRQ;
    NVIC_Init(&NVIC_InitStructure);
}

void Key_ISR(uint8_t key)
{
    OS_ERR err;
    EXTI_ClearITPendingBit(key == 0 ? KEY0_EXTI_LINE : key == 1 ? KEY1_EXTI_LINE : KEY2_EXTI_LINE);
    OSSemPost(key_sem, OS_OPT_POST_ALL, &err);
}

void Key_Task(void* pdata)
{
    OS_ERR err;
    uint8_t key;
    while (1) {
        OSSemPend(key_sem, 0, OS_OPT_PEND_BLOCKING, NULL, &err);
        if (GPIO_ReadInputDataBit(KEY0_GPIO_PORT, KEY0_GPIO_PIN) == RESET) {
            key = 0;
        } else if (GPIO_ReadInputDataBit(KEY1_GPIO_PORT, KEY1_GPIO_PIN) == RESET) {
            key = 1;
        } else if (GPIO_ReadInputDataBit(KEY2_GPIO_PORT, KEY2_GPIO_PIN) == RESET) {
            key = 2;
        }
        // 处理按键按下事件
        printf("Key%d pressed!\r\n", key);
    }
}

int main(void)
{
    OS_ERR err;
    OSInit();
    Key_Init();
    key_sem = OSSemCreate(0, &err);
    OSTaskCreate(Key_Task, NULL, OSTaskStkChk, 10, 0, NULL, &err);
    OSStart();
    return 0;
}

void HardFault_Handler(void)
{
    while (1);
}

上述代码中，`Key_Init()`函数用于初始化三个按键所对应的GPIO口、中断线和中断服务函数。在中断服务函数`Key_ISR()`中，使用`OSSemPost()`函数发送信号量，以通知任务处理按键按下事件。而在任务函数`Key_Task()`中，则使用`OSSemPend()`函数等待信号量，并在信号量被触发时通过GPIO口读取按键状态，从而确定是哪个按键被按下，并处理相应的事件。