用UCOS3写一个串口通信程序

以下是一个基于UCOS3的串口通信程序示例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "stm32f4xx.h"
#include "os.h"
#include "app_cfg.h"

#define UART_RX_BUF_SIZE    64
#define UART_TX_BUF_SIZE    64

// 串口接收缓冲区
static CPU_CHAR uart_rx_buf[UART_RX_BUF_SIZE];

// 串口发送缓冲区
static CPU_CHAR uart_tx_buf[UART_TX_BUF_SIZE];

// 串口接收信号量
static OS_SEM uart_rx_sem;

// 串口句柄
static USART_TypeDef *uart = USART2;

// 串口中断处理函数
void USART2_IRQHandler(void)
{
    OSIntEnter();

    if (USART_GetITStatus(uart, USART_IT_RXNE) != RESET)
    {
        // 读取接收到的数据
        CPU_CHAR data = USART_ReceiveData(uart);
        // 将数据存入接收缓冲区
        OS_ERR err;
        OSSemPend(&uart_rx_sem, 0, OS_OPT_PEND_BLOCKING, NULL, &err);
        uart_rx_buf[strlen(uart_rx_buf)] = data;
        OSSemPost(&uart_rx_sem, OS_OPT_POST_1, &err);
    }

    OSIntExit();
}

// 初始化串口
void uart_init(void)
{
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

    GPIO_InitTypeDef GPIO_InitStruct;
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART2);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_USART2);

    USART_InitTypeDef USART_InitStruct;
    USART_InitStruct.USART_BaudRate = 9600;
    USART_InitStruct.USART_WordLength = USART_WordLength_8b;
    USART_InitStruct.USART_StopBits = USART_StopBits_1;
    USART_InitStruct.USART_Parity = USART_Parity_No;
    USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStruct.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_Init(USART2, &USART_InitStruct);

    USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);

    NVIC_InitTypeDef NVIC_InitStruct;
    NVIC_InitStruct.NVIC_IRQChannel = USART2_IRQn;
    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStruct);

    USART_Cmd(USART2, ENABLE);

    OS_ERR err;
    OSSemCreate(&uart_rx_sem, "UART RX Sem", 1, &err);
}

// 发送数据
void uart_send(CPU_CHAR *data)
{
    CPU_INT08U len = strlen(data);
    CPU_INT08U i;
    for (i = 0; i < len; i++)
    {
        USART_SendData(uart, data[i]);
        while (USART_GetFlagStatus(uart, USART_FLAG_TXE) == RESET);
    }
}

// 接收数据
CPU_CHAR *uart_receive(void)
{
    OS_ERR err;
    OSSemPend(&uart_rx_sem, 0, OS_OPT_PEND_BLOCKING, NULL, &err);
    CPU_CHAR *data = uart_rx_buf;
    uart_rx_buf[0] = '\0';
    OSSemPost(&uart_rx_sem, OS_OPT_POST_1, &err);
    return data;
}

// 串口任务
void uart_task(void *p_arg)
{
    while (1)
    {
        // 接收并处理数据
        CPU_CHAR *data = uart_receive();
        printf("Received data: %s\n", data);
        // 发送数据
        uart_send("Hello, world!\n");
        OSTimeDlyHMSM(0, 0, 0, 500, OS_OPT_TIME_HMSM_STRICT, NULL);
    }
}

int main(void)
{
    OS_ERR err;
    OSInit(&err);

    uart_init();

    OSTaskCreate((OS_TCB *)&AppTaskStartTCB,                               /* Create the start task                                    */
                 (CPU_CHAR *)"Start Task",
                 (OS_TASK_PTR)AppTaskStart,
                 (void *)0,
                 (OS_PRIO)APP_CFG_TASK_START_PRIO,
                 (CPU_STK *)&AppTaskStartStk[0],
                 (CPU_STK_SIZE)APP_CFG_TASK_START_STK_SIZE_LIMIT,
                 (CPU_STK_SIZE)APP_CFG_TASK_START_STK_SIZE,
                 (OS_MSG_QTY)0u,
                 (OS_TICK)0u,
                 (void *)0,
                 (OS_OPT)(OS_OPT_TASK_STK_CHK | OS_OPT_TASK_STK_CLR),
                 (OS_ERR *)&err);

    OSStart(&err);

    while (1);
}

在该示例中，我们使用了USART2作为串口，并在串口中断处理函数中将接收到的数据存入接收缓冲区，并通过信号量进行同步。在串口任务中，我们通过调用uart_receive函数从接收缓冲区中获取数据，并通过调用uart_send函数发送数据到串口。