基于小凌派RK2206开发板：OpenHarmony如何使用IoT接口

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

unsignedintIoTUartInit(unsignedintid,constIotUartAttribute*param);

描述：

UART设备初始化。

参数：

UART ID配置和IO复用如下表：

返回值：

实现：

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

unsignedintIoTUartInit(unsignedintid,constIotUartAttribute*param)
{
unsignedintret=0;
UartAttribute*temp_prt=(constUartAttribute*)param;

if(id>=EUARTDEV_MAX)
{
PRINT_ERR("id(%d) >= EUARTDEV_MAX(%d)\n",id,EUARTDEV_MAX);
returnIOT_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;
}
elseif(param->parity==IOT_UART_PARITY_EVEN)
{
temp_prt->parity=UART_PARITY_EVEN;
}
elseif(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)
{
returnIOT_FAILURE;
}

returnIOT_SUCCESS;
}

2.3、取消初始化UART设备：IoTUartDeinit

unsignedintIoTUartDeinit(unsignedintid);

描述：

取消初始化UART设备。

参数：

UART ID配置和IO复用如下表：

返回值：

实现：

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

unsignedintIoTUartDeinit(unsignedintid)
{
unsignedintret=0;

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

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

returnIOT_SUCCESS;
}

2.4、UART设备读取指定长度的数据：IoTUartRead

intIoTUartRead(unsignedintid,unsignedchar*data,unsignedintdataLen);

描述：

UART设备读取指定长度的数据。

参数：

UART ID配置和IO复用如下表：

返回值：

实现：

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

intIoTUartRead(unsignedintid,unsignedchar*data,unsignedintdataLen)
{
unsignedintret=0;

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

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

returnret;
}

2.5、UART设备写指定长度的数据：IoTUartWrite

intIoTUartWrite(unsignedintid,constunsignedchar*data,unsignedintdataLen);

描述：

UART设备读取指定长度的数据。

参数：

UART ID配置和IO复用如下表：

返回值：

实现：

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

intIoTUartWrite(unsignedintid,constunsignedchar*data,unsignedintdataLen)
{
unsignedintret=0;

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

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

returnIOT_SUCCESS;
}

3、程序设计

主要代码分析

在uart_example函数中，创建一个任务。

voiduart_example()
{
unsignedintthread_id;
TSK_INIT_PARAM_Stask={0};
unsignedintret =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。

voiduart_thread()
{
unsignedintret;
IotUartAttributeattr;
unsignedcharstr[] ="HelloWorld!";
unsignedcharrecv_buffer[STRING_MAXSIZE]={0};
unsignedintrecv_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：

enteringkernelinit...
hilogwillinit.
[MAIN:D]Main:LOS_Start...
Enteringscheduler
OHOS# hiview init success.[UART:E]LzUartDeinit: id 0, controller has NOT been initialized
[UART:E]LzUartDeinit:id0,controllerhasNOTbeeninitialized
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c,63:uartwriteandstr(HelloWorld!),len(11)!
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c,72:uartrecvandstr(HelloWorld!),len(11)
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c,63:uartwriteandstr(HelloWorld!),len(11)!
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c,72:uartrecvandstr(HelloWorld!),len(11)
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c,63:uartwriteandstr(HelloWorld!),len(11)!
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c,72:uartrecvandstr(HelloWorld!),len(11)
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c,63:uartwriteandstr(HelloWorld!),len(11)!
../../../vendor/lockzhiner/rk2206/samples/b20_iot_uart/iot_uart_example.c,72:uartrecvandstr(HelloWorld!),len(11)