目录
概述
1 硬件介绍
2 软件配置
2.1 RT-Thread Studio配置参数
2.2 FSP配置MCU
3 RT-Thread中UART的接口介绍
3.1 RT-Thread UART简介
3.2 RT-Thread 下的UART接口
4 UART的应用
4.1 应用功能实现
4.2 源代码文件
5 测试
程序下载地址：
RenesaVersionBoard开发RT-Thread之UART驱动应用资源-CSDN文库
概述
本文主要介绍RT-Thread下UART接口的使用方法，笔者使用Renesa Version Board开发板，其开放的UART端口为UART2。文章介绍了使用RT-Studio使能UART，使用FSP配置和使能UART-2，然后编写基于RT-Thread下UART的驱动接口，并测试其功能。
1 硬件介绍
Renesa Version Board开发板扩展接口上提供一个UART接口，其对应Pin引脚为：
| Renesa Version Board | 功能定义 |
| P802 | RX |
| P801 | TX |
2 软件配置
2.1 RT-Thread Studio配置参数
点击RT-thread Settings， 在Hardware中使能UART2，并保存配置信息
2.2 FSP配置MCU
1) 在RT-Thread Studio中点击FSP，打开该软件
2）配置SCI下的UART
3） 创建UART对应的stack
4） 完成以上参数配置后就可以生成项目文件
在hal_data.c文件中，看见和uart相关的代码：
sci_b_uart_instance_ctrl_t g_uart2_ctrl;sci_b_baud_setting_t g_uart2_baud_setting ={/* Baud rate calculated with 0.160% error. */ .baudrate_bits_b.abcse = 0, .baudrate_bits_b.abcs = 0, .baudrate_bits_b.bgdm = 1, .baudrate_bits_b.cks = 0, .baudrate_bits_b.brr = 64, .baudrate_bits_b.mddr = (uint8_t) 256, .baudrate_bits_b.brme = false};/** UART extended configuration for UARTonSCI HAL driver */const sci_b_uart_extended_cfg_t g_uart2_cfg_extend ={.clock = SCI_B_UART_CLOCK_INT,.rx_edge_start = SCI_B_UART_START_BIT_FALLING_EDGE,.noise_cancel = SCI_B_UART_NOISE_CANCELLATION_DISABLE,.rx_fifo_trigger = SCI_B_UART_RX_FIFO_TRIGGER_MAX,.p_baud_setting = &g_uart2_baud_setting,.flow_control = SCI_B_UART_FLOW_CONTROL_RTS,#if 0xFF != 0xFF.flow_control_pin = BSP_IO_PORT_FF_PIN_0xFF,#else.flow_control_pin = (bsp_io_port_pin_t) UINT16_MAX,#endif.rs485_setting = {.enable = SCI_B_UART_RS485_DISABLE,.polarity = SCI_B_UART_RS485_DE_POLARITY_HIGH,.assertion_time = 1,.negation_time = 1,}};/** UART interface configuration */const uart_cfg_t g_uart2_cfg ={.channel = 2,.data_bits = UART_DATA_BITS_8,.parity = UART_PARITY_OFF,.stop_bits = UART_STOP_BITS_1,.p_callback = g_uart2_Callback,.p_context = NULL,.p_extend = &g_uart2_cfg_extend,
#define RA_NOT_DEFINED (1)
#if (RA_NOT_DEFINED == RA_NOT_DEFINED).p_transfer_tx = NULL,
#else.p_transfer_tx = &RA_NOT_DEFINED,
#endif
#if (RA_NOT_DEFINED == RA_NOT_DEFINED).p_transfer_rx = NULL,
#else.p_transfer_rx = &RA_NOT_DEFINED,
#endif
#undef RA_NOT_DEFINED.rxi_ipl = (12),.txi_ipl = (12),.tei_ipl = (12),.eri_ipl = (12),
#if defined(VECTOR_NUMBER_SCI2_RXI).rxi_irq = VECTOR_NUMBER_SCI2_RXI,
#else.rxi_irq = FSP_INVALID_VECTOR,
#endif
#if defined(VECTOR_NUMBER_SCI2_TXI).txi_irq = VECTOR_NUMBER_SCI2_TXI,
#else.txi_irq = FSP_INVALID_VECTOR,
#endif
#if defined(VECTOR_NUMBER_SCI2_TEI).tei_irq = VECTOR_NUMBER_SCI2_TEI,
#else.tei_irq = FSP_INVALID_VECTOR,
#endif
#if defined(VECTOR_NUMBER_SCI2_ERI).eri_irq = VECTOR_NUMBER_SCI2_ERI,
#else.eri_irq = FSP_INVALID_VECTOR,
#endif};/* Instance structure to use this module. */
const uart_instance_t g_uart2 =
{.p_ctrl = &g_uart2_ctrl,.p_cfg = &g_uart2_cfg,.p_api = &g_uart_on_sci_b
};3 RT-Thread中UART的接口介绍
3.1 RT-Thread UART简介
RT-Thread官方网站提供了有关UART使用的详细介绍，其网站地址如下：
https://www.rt-thread.org/document/site/#/rt-thread-version/rt-thread-standard/programming-manual/device/uart/uart_v1/uart打开网站后，可以看见如下页面：
3.2 RT-Thread 下的UART接口
应用程序通过 RT-Thread提供的 I/O 设备管理接口来访问串口硬件，相关接口如下所示：
| 函数 | 描述 |
|---|---|
| rt_device_find() | 查找设备 |
| rt_device_open() | 打开设备 |
| rt_device_read() | 读取数据 |
| rt_device_write() | 写入数据 |
| rt_device_control() | 控制设备 |
| rt_device_set_rx_indicate() | 设置接收回调函数 |
| rt_device_set_tx_complete() | 设置发送完成回调函数 |
| rt_device_close() | 关闭设备 |
一个使用范例：
void test_uart( void )
{#define SAMPLE_UART_NAME "uart2" /* 串口设备名称 */static rt_device_t serial; /* 串口设备句柄 */char str[] = "hello RT-Thread!\r\n";struct serial_configure config = RT_SERIAL_CONFIG_DEFAULT; /* 配置参数 *//* 查找串口设备 */serial = rt_device_find(SAMPLE_UART_NAME);/* 以中断接收及轮询发送模式打开串口设备 */rt_device_open(serial, RT_DEVICE_FLAG_INT_RX);/* 发送字符串 */rt_device_write(serial, 0, str, (sizeof(str) - 1));
}4 UART的应用
4.1 应用功能实现
编写一个函数，实现发送字符串的功能，在PC端口使用调试助手接收数据
代码16行： 定义设备信息
代码29行： 创建接收句柄
代码41行： 查找设备
代码44行： 打开串口，同时使能接收和发送功能
代码46行：发送字符串
发送数据函数接口：
回调函数接口，中断函数会调用该函数，程序员只需调用相关的接口就能进行数据处理。
4.2 源代码文件
创建comm_uart.c文件，编写如下代码：
/** Copyright (c) 2006-2021, RT-Thread Development Team** SPDX-License-Identifier: Apache-2.0** Change Logs:* Date Author Notes* 2024-08-25 Administrator the first version*/
#include "hal_data.h"
#include "comm_uart.h"#define TRANSFER_LENGTH 128#define SAMPLE_UART_NAME "uart2" /* 串口设备名称 */
/* 接收模式参数 */
#define RT_DEVICE_FLAG_RX_BLOCKING 0x1000 /* 接收阻塞模式 */#define RT_DEVICE_FLAG_RX_NON_BLOCKING 0x2000 /* 接收非阻塞模式 *//* 发送模式参数 */
#define RT_DEVICE_FLAG_TX_BLOCKING 0x4000 /* 发送阻塞模式 */#define RT_DEVICE_FLAG_TX_NON_BLOCKING 0x8000 /* 发送非阻塞模式 */#define RT_DEVICE_FLAG_STREAM 0x040 /* 流模式 */static rt_device_t serial; /* 串口设备句柄 */
uint8_t g_out_of_band_received[TRANSFER_LENGTH];
uint32_t g_transfer_complete = 0;
uint32_t g_receive_complete = 0;
uint32_t g_out_of_band_index = 0;void comm_uartInit( void )
{char str[] = "hello RT-Thread, I am uart2!\r\n";/* 查找串口设备 */serial = rt_device_find(SAMPLE_UART_NAME);// 串口设备使用模式为 (发送阻塞 接收非阻塞) 模式rt_device_open(serial,RT_DEVICE_FLAG_RX_NON_BLOCKING | RT_DEVICE_FLAG_TX_BLOCKING);rt_device_write(serial, 0, str, (sizeof(str) - 1));
}void com_uartSend( char *buff, int len )
{rt_device_write(serial, 0, buff, len);
}void com_uartTest( void )
{char str[] = "hello RT-Thread, I am uart2!\r\n";rt_device_write(serial, 0, str, (sizeof(str) - 1));
}void g_uart2_Callback (uart_callback_args_t * p_args)
{/* Handle the UART event */switch (p_args->event){/* Received a character */case UART_EVENT_RX_CHAR:{/* Only put the next character in the receive buffer if there is space for it */if (sizeof(g_out_of_band_received) > g_out_of_band_index){/* Write either the next one or two bytes depending on the receive data size */if (UART_DATA_BITS_8 >= g_uart2_cfg.data_bits){g_out_of_band_received[g_out_of_band_index++] = (uint8_t) p_args->data;}else{uint16_t * p_dest = (uint16_t *) &g_out_of_band_received[g_out_of_band_index];*p_dest = (uint16_t) p_args->data;g_out_of_band_index += 2;}}else {g_out_of_band_index = 0;}break;}/* Receive complete */case UART_EVENT_RX_COMPLETE:{g_receive_complete = 1;break;}/* Transmit complete */case UART_EVENT_TX_COMPLETE:{g_transfer_complete = 1;break;}default:{}}
}5 测试
编译代码，下载到板卡中，在终端输入如下命令，查看UART-2是否被使能
list device
编写一个测试函数，在主函数中发送字符串：
void com_uartTest( void )
{char str[] = "hello RT-Thread, I am uart2!\r\n";rt_device_write(serial, 0, str, (sizeof(str) - 1));
}运行代码，在串口终端上可以看见：
