101 lines
2.7 KiB
C
101 lines
2.7 KiB
C
/*
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* Copyright (c) 2006-2018, RT-Thread Development Team
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Change Logs:
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* Date Author Notes
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* 2018-08-15 misonyo first implementation.
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*/
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/*
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* 程序清单：这是一个 串口 设备使用例程
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* 例程导出了 uart_sample 命令到控制终端
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* 命令调用格式：uart_sample uart2
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* 命令解释：命令第二个参数是要使用的串口设备名称，为空则使用默认的串口设备
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* 程序功能：通过串口输出字符串"hello RT-Thread!"，然后错位输出输入的字符
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*/
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#include <rtthread.h>
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#define SAMPLE_UART_NAME "uart0" /* 串口设备名称 */
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/* 用于接收消息的信号量 */
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static struct rt_semaphore rx_sem;
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static rt_device_t serial;
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/* 接收数据回调函数 */
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static rt_err_t uart_input(rt_device_t dev, rt_size_t size)
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{
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/* 串口接收到数据后产生中断，调用此回调函数，然后发送接收信号量 */
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rt_sem_release(&rx_sem);
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return RT_EOK;
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}
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static void serial_thread_entry(void *parameter)
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{
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char ch;
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while (1)
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{
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/* 从串口读取一个字节的数据，没有读取到则等待接收信号量 */
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while (rt_device_read(serial, -1, &ch, 1) != 1)
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{
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/* 阻塞等待接收信号量，等到信号量后再次读取数据 */
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rt_sem_take(&rx_sem, RT_WAITING_FOREVER);
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}
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/* 读取到的数据通过串口错位输出 */
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ch = ch + 1;
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rt_device_write(serial, 0, &ch, 1);
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}
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}
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static int uart_sample(int argc, char *argv[])
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{
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rt_err_t ret = RT_EOK;
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char uart_name[RT_NAME_MAX];
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char str[] = "hello RT-Thread!\r\n";
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if (argc == 2)
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{
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rt_strncpy(uart_name, argv[1], RT_NAME_MAX);
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}
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else
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{
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rt_strncpy(uart_name, SAMPLE_UART_NAME, RT_NAME_MAX);
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}
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/* 查找串口设备 */
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serial = rt_device_find(uart_name);
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if (!serial)
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{
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rt_kprintf("find %s failed!\n", uart_name);
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return RT_ERROR;
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}
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/* 初始化信号量 */
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rt_sem_init(&rx_sem, "rx_sem", 0, RT_IPC_FLAG_FIFO);
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/* 以中断接收及轮询发送方式打开串口设备 */
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rt_device_open(serial, RT_DEVICE_FLAG_INT_RX);
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/* 设置接收回调函数 */
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rt_device_set_rx_indicate(serial, uart_input);
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/* 发送字符串 */
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rt_device_write(serial, 0, str, (sizeof(str) - 1));
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/* 创建 serial 线程 */
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rt_thread_t thread = rt_thread_create("serial", serial_thread_entry, RT_NULL, 1024, 25, 10);
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/* 创建成功则启动线程 */
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if (thread != RT_NULL)
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{
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rt_thread_startup(thread);
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}
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else
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{
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ret = RT_ERROR;
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}
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return ret;
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}
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/* 导出到 msh 命令列表中 */
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MSH_CMD_EXPORT(uart_sample, uart device sample);
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