基于小凌派RK2206开发板：OpenHarmony如何使用IoT接口控制UART外设 原创

1、实验简介

本实验将演示如何在小凌派-RK2206开发板上使用IOT库的UART接口，进行UART编程开发。

例程将创建一个任务，通过配置UART引脚，实现UART读写操作。

例程源代码：https://gitee.com/Lockzhiner-Electronics/lockzhiner-rk2206-openharmony3.0lts/tree/master/vendor/lockzhiner/rk2206/samples/b20_iot_uart

2、基础知识

UART在日常设备中非常常见，以下我们将演示IOT库的UART接口如何进行UART口配置，以及UART口读写操作。

2.1、头文件

base/iot_hardware/peripheral/interfaces/kits/iot_uart.h

2.2、UART设备初始化：IoTUartInit

unsigned int IoTUartInit(unsigned int id, const IotUartAttribute *param);

描述：

UART设备初始化。

参数：

参数	类型	描述
id	unsigned int	UART ID
param	const IotUartAttribute *	UART配置参数

UART ID配置和IO复用如下表：

串口	id	TX	RX
UART0	EUART0_M0	GPIO0_PB7	GPIO0_PB6
UART0	EUART0_M1	GPIO0_PC7	GPIO0_PC6
UART1	EUART1_M0	GPIO0_PC3	GPIO0_PC2
UART1	EUART1_M1	GPIO0_PA7	GPIO0_PA6
UART2	EUART2_M1	GPIO0_PB3	GPIO0_PB2

返回值：

返回值	描述
IOT_SUCCESS	成功
IOT_FAILURE	失败

实现：

hal_iot_uart.c文件在device/rockchip/rk2206/adapter/hals/iot_hardware/wifiiot_lite目录下。

unsigned int IoTUartInit(unsigned int id, const IotUartAttribute *param)
{
    unsigned int ret = 0;
    UartAttribute *temp_prt = (const UartAttribute *)param;

    if (id >= EUARTDEV_MAX)
    {
        PRINT_ERR("id(%d) >= EUARTDEV_MAX(%d)\n", id, EUARTDEV_MAX);
        return IOT_FAILURE;
    }

    PinctrlSet(m_uart_bus_info[id].uart_bus.rx.gpio, m_uart_bus_info[id].uart_bus.rx.func, m_uart_bus_info[id].uart_bus.rx.type, m_uart_bus_info[id].uart_bus.rx.drv);
    PinctrlSet(m_uart_bus_info[id].uart_bus.tx.gpio, m_uart_bus_info[id].uart_bus.tx.func, m_uart_bus_info[id].uart_bus.tx.type, m_uart_bus_info[id].uart_bus.tx.drv);

    if (param->parity == IOT_UART_PARITY_NONE)
    {
        temp_prt->parity = UART_PARITY_NONE;
    }
    else if (param->parity == IOT_UART_PARITY_EVEN)
    {
        temp_prt->parity = UART_PARITY_EVEN;
    }
    else if (param->parity == IOT_UART_PARITY_ODD)
    {
        temp_prt->parity = UART_PARITY_ODD;
    }

    if (m_uart_bus_info[id].id == 0)
    {
        LzUartDeinit(m_uart_bus_info[id].id);
        uint32_t *pUart0 = (uint32_t *)(0x40070000U);
        HAL_UART_DeInit(pUart0);
    }

    ret = LzUartInit(m_uart_bus_info[id].id, temp_prt);
    if (ret != LZ_HARDWARE_SUCCESS)
    {
        return IOT_FAILURE;
    }

    return IOT_SUCCESS;
}

2.3、取消初始化UART设备：IoTUartDeinit

unsigned int IoTUartDeinit(unsigned int id);

描述：

取消初始化UART设备。

参数：

参数	类型	描述
id	unsigned int	UART ID

UART ID配置和IO复用如下表：

串口	id	TX	RX
UART0	EUART0_M0	GPIO0_PB7	GPIO0_PB6
UART0	EUART0_M1	GPIO0_PC7	GPIO0_PC6
UART1	EUART1_M0	GPIO0_PC3	GPIO0_PC2
UART1	EUART1_M1	GPIO0_PA7	GPIO0_PA6
UART2	EUART2_M1	GPIO0_PB3	GPIO0_PB2

返回值：

返回值	描述
IOT_SUCCESS	成功
IOT_FAILURE	失败

实现：

hal_iot_uart.c文件在device/rockchip/rk2206/adapter/hals/iot_hardware/wifiiot_lite目录下。

unsigned int IoTUartDeinit(unsigned int id)
{
    unsigned int ret = 0;

    if (id >= EUARTDEV_MAX)
    {
        PRINT_ERR("id(%d) >= EUARTDEV_MAX(%d)\n", id, EUARTDEV_MAX);
        return IOT_FAILURE;
    }

    ret = LzUartDeinit(m_uart_bus_info[id].id);
    if (ret != LZ_HARDWARE_SUCCESS)
    {
        return IOT_FAILURE;
    }

    return IOT_SUCCESS;
}

2.4、UART设备读取指定长度的数据：IoTUartRead

int IoTUartRead(unsigned int id, unsigned char *data, unsigned int dataLen);

描述：

UART设备读取指定长度的数据。

参数：

参数	类型	描述
id	unsigned int	UART ID
data	unsigned char *	数据指针
dataLen	unsigned int	数据长度

UART ID配置和IO复用如下表：

串口	id	TX	RX
UART0	EUART0_M0	GPIO0_PB7	GPIO0_PB6
UART0	EUART0_M1	GPIO0_PC7	GPIO0_PC6
UART1	EUART1_M0	GPIO0_PC3	GPIO0_PC2
UART1	EUART1_M1	GPIO0_PA7	GPIO0_PA6
UART2	EUART2_M1	GPIO0_PB3	GPIO0_PB2

返回值：

返回值	描述
IOT_SUCCESS	成功
IOT_FAILURE	失败

实现：

hal_iot_uart.c文件在device/rockchip/rk2206/adapter/hals/iot_hardware/wifiiot_lite目录下。

int IoTUartRead(unsigned int id, unsigned char *data, unsigned int dataLen)
{
    unsigned int ret = 0;

    if (id >= EUARTDEV_MAX)
    {
        PRINT_ERR("id(%d) >= EUARTDEV_MAX(%d)\n", id, EUARTDEV_MAX);
        return IOT_FAILURE;
    }

    ret = LzUartRead(m_uart_bus_info[id].id, data, dataLen);

    return ret;
}

2.5、UART设备写指定长度的数据：IoTUartWrite

int IoTUartWrite(unsigned int id, const unsigned char *data, unsigned int dataLen);

描述：

UART设备读取指定长度的数据。

参数：

参数	类型	描述
id	unsigned int	UART ID
data	const unsigned char *	数据指针
dataLen	unsigned int	数据长度

UART ID配置和IO复用如下表：

串口	id	TX	RX
UART0	EUART0_M0	GPIO0_PB7	GPIO0_PB6
UART0	EUART0_M1	GPIO0_PC7	GPIO0_PC6
UART1	EUART1_M0	GPIO0_PC3	GPIO0_PC2
UART1	EUART1_M1	GPIO0_PA7	GPIO0_PA6
UART2	EUART2_M1	GPIO0_PB3	GPIO0_PB2

返回值：

返回值	描述
IOT_SUCCESS	成功
IOT_FAILURE	失败

实现：

hal_iot_uart.c文件在device/rockchip/rk2206/adapter/hals/iot_hardware/wifiiot_lite目录下。

int IoTUartWrite(unsigned int id, const unsigned char *data, unsigned int dataLen)
{
    unsigned int ret = 0;

    if (id >= EUARTDEV_MAX)
    {
        PRINT_ERR("id(%d) >= EUARTDEV_MAX(%d)\n", id, EUARTDEV_MAX);
        return IOT_FAILURE;
    }

    ret = LzUartWrite(m_uart_bus_info[id].id, data, dataLen);
    if (ret != LZ_HARDWARE_SUCCESS)
    {
        return IOT_FAILURE;
    }

    return IOT_SUCCESS;
}

3、程序设计

主要代码分析

在uart_example函数中，创建一个任务。

void uart_example()
{
    unsigned int thread_id;
    TSK_INIT_PARAM_S task = {0};
    unsigned int ret      = LOS_OK;

    task.pfnTaskEntry = (TSK_ENTRY_FUNC)uart_thread;
    task.uwStackSize  = 2048;
    task.pcName       = "uart_thread";
    task.usTaskPrio   = 24;
    ret               = LOS_TaskCreate(&thread_id, &task);
    if (ret != LOS_OK) {
        printf("Falied to create uart_thread ret:0x%x\n", ret);
        return;
    }
}

uart_thread任务中调用IOT库的UART接口配置、读写UART。

void uart_thread()
{
    unsigned int ret;
    IotUartAttribute attr;
    unsigned char str[]                       = "HelloWorld!";
    unsigned char recv_buffer[STRING_MAXSIZE] = {0};
    unsigned int recv_length                  = 0;

    IoTUartDeinit(UART_ID);

    attr.baudRate = 115200;
    attr.dataBits = IOT_UART_DATA_BIT_8;
    attr.pad      = IOT_FLOW_CTRL_NONE;
    attr.parity   = IOT_UART_PARITY_NONE;
    attr.rxBlock  = IOT_UART_BLOCK_STATE_NONE_BLOCK;
    attr.stopBits = IOT_UART_STOP_BIT_1;
    attr.txBlock  = IOT_UART_BLOCK_STATE_NONE_BLOCK;

    /* 初始化串口 */
    ret = IoTUartInit(UART_ID, &attr);
    if (ret != IOT_SUCCESS) {
        printf("%s, %d: IoTUartInit(%d) failed!\n", __FILE__, __LINE__, ret);
        return;
    }
    /* 休眠1秒 */
    LOS_Msleep(1000);

    while (1) {
        printf("%s, %d: uart write and str(%s), len(%d)!\n", __FILE__, __LINE__, str, strlen(str));
        // IoTUartWrite是异步发送，非阻塞发送
        IoTUartWrite(UART_ID, str, strlen(str));
        // 等待发送完毕
        LOS_Msleep(1000);

        recv_length = 0;
        memset(recv_buffer, 0, sizeof(recv_buffer));
        recv_length = IoTUartRead(UART_ID, recv_buffer, sizeof(recv_buffer));
        printf("%s, %d: uart recv and str(%s), len(%d)\n", __FILE__, __LINE__, recv_buffer, recv_length);

        /* 休眠1秒 */
        LOS_Msleep(1000);
    }
}

4、编译调试

修改 vendor/lockzhiner/rk2206/sample 路径下 BUILD.gn 文件，指定 iot_uart_example 参与编译。

"./b20_iot_uart:iot_uart_example",

修改 device/lockzhiner/rk2206/sdk_liteos 路径下 Makefile 文件，添加 -liot_uart_example 参与编译。

hardware_LIBS = -lhal_iothardware -lhardware -lshellcmd -liot_uart_example

5、运行结果

示例代码编译烧录代码后，按下开发板的RESET按键，使用杜邦线连接TX和RX，通过串口助手查看日志，显示如下：

entering kernel init...
hilog will init.
[MAIN:D]Main: LOS_Start ...
Entering scheduler
OHOS # hiview init success.[UART:E]LzUartDeinit: id 0, controller has NOT been initialized
[UART:E]LzUartDeinit: id 0, controller has NOT been initialized
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c, 63: uart write and str(HelloWorld!), len(11)!
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c, 72: uart recv and str(HelloWorld!), len(11)
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c, 63: uart write and str(HelloWorld!), len(11)!
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c, 72: uart recv and str(HelloWorld!), len(11)
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c, 63: uart write and str(HelloWorld!), len(11)!
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c, 72: uart recv and str(HelloWorld!), len(11)
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c, 63: uart write and str(HelloWorld!), len(11)!
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c, 72: uart recv and str(HelloWorld!), len(11)