UCOSIII外部中断控制按键代码

下面是一个简单的UCOSIII外部中断控制按键的代码示例：

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

#define KEY_GPIO_PORT   GPIOA
#define KEY_GPIO_PIN    GPIO_Pin_0
#define KEY_EXTI_LINE   EXTI_Line0
#define KEY_EXTI_PORT   EXTI_PortSourceGPIOA
#define KEY_EXTI_PIN    EXTI_PinSource0
#define KEY_EXTI_IRQ    EXTI0_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, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);

    GPIO_InitStructure.GPIO_Pin = KEY_GPIO_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(KEY_GPIO_PORT, &GPIO_InitStructure);

    SYSCFG_EXTILineConfig(KEY_EXTI_PORT, KEY_EXTI_PIN);

    EXTI_InitStructure.EXTI_Line = KEY_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);

    NVIC_InitStructure.NVIC_IRQChannel = KEY_EXTI_IRQ;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0f;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0f;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}

void Key_ISR(void)
{
    OS_ERR err;
    EXTI_ClearITPendingBit(KEY_EXTI_LINE);
    OSSemPost(key_sem, OS_OPT_POST_ALL, &err);
}

void Key_Task(void* pdata)
{
    OS_ERR err;
    while (1) {
        OSSemPend(key_sem, 0, OS_OPT_PEND_BLOCKING, NULL, &err);
        // 处理按键按下事件
        printf("Key pressed!\r\n");
    }
}

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处理按键按下事件。