学习目标

  • 掌握串口的代码编写和调试

    学习内容

    串口

    131.png136.png

  • P11为Uart2_TXD

  • P13为Uart2_RXD

    案例设计

  1. Hi3861的串口2（Uart2）和STC8的串口进行通讯
  2. HI3861的串口2定时发送消息给STC8
  3. HI3861的串口2收到消息后，通过printf输出到控制台。

    串口初始化

    ```c //初始化GPIO口 IoTGpioInit(IOT_IO_NAME_11); //设置IO口功能为GPIO IoTGpioSetFunc(IOT_IO_NAME_11, IOT_GPIO_FUNC_GPIO_11_UART2_TXD);

IoTGpioInit(IOT_IO_NAME_12); //设置IO口功能为GPIO IoTGpioSetFunc(IOT_IO_NAME_12, IOT_GPIO_FUNC_GPIO_12_UART2_RXD);

IotUartAttribute attr; attr.baudRate = 115200; //波特率 attr.dataBits = 8; //数据位 attr.stopBits = 1; // 停止位 attr.parity = IOT_UART_PARITY_NONE; //是否奇偶校验 attr.rxBlock = IOT_UART_BLOCK_STATE_NONE_BLOCK; // 是否为阻塞式 attr.txBlock = IOT_UART_BLOCK_STATE_NONE_BLOCK; // 是否为阻塞式 attr.pad = 0;//padding bit，占位空字符 IoTUartInit(IDX, &attr);

  1. <a name="lSmBq"></a>
  2. #### 开发流程
  3. 来到应用开发的**根目录。**<br />我们编写代码的**根目录**为`device/board/itcast/genkipi/app`。
  5. 1. **根目录**下新建`uart_demo`文件夹，此为**项目目录**。
  6. 2. 此**项目目录**下新建`main.c`文件
  7. 3. 此**项目目录**下新建`BUILD.gn`文件
  8. 4. 修改**根目录**下的`BUILD.gn`文件
  9. <a name="pbSC0"></a>
  10. #### 代码部分
  11. ```c
  12. /*
  13.  * Copyright (C) 2020 Itcast Co., Ltd. All rights reserved.
  14.  * Licensed under the Apache License, Version 2.0 (the "License");
  15.  * you may not use this file except in compliance with the License.
  16.  * You may obtain a copy of the License at
  17.  *
  18.  *    http://www.apache.org/licenses/LICENSE-2.0
  19.  *
  20.  * Unless required by applicable law or agreed to in writing, software
  21.  * distributed under the License is distributed on an "AS IS" BASIS,
  22.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  23.  * See the License for the specific language governing permissions and
  24.  * limitations under the License.
  25.  */
  27. #include <stdio.h>
  28. #include <string.h>
  29. #include <unistd.h>
  31. #include "cmsis_os2.h"
  32. #include "ohos_init.h"
  34. #include "iot_gpio.h"
  35. #include "iot_gpio_ex.h"
  36. #include "iot_uart.h"
  38. #define IDX 2
  40. static void uart_write(void) {
  41.     unsigned char data[256];
  42.     int cnt = 0;
  43.     while (1)
  44.     {
  45.         sprintf(data, "nice %d\r\n", cnt++);
  46.         IoTUartWrite(IDX, data, strlen(data));
  48.         usleep(2 * 1000 * 1000);
  49.     }
  50. }
  52. static void uart_read(void) {
  53.     unsigned char data[256];
  54.     int len = 0;
  55.     while (1)
  56.     {
  57.         len = IoTUartRead(IDX, data, 256);
  58.         if(len <= 0) {
  59.             usleep(20 * 1000);
  60.             continue;
  61.         }
  63.         data[len] = '\0';
  64.         printf("recv: %s\r\n", data);
  65.         usleep(20 * 1000);
  66.     }
  67. }
  69. static void start_read_task() {
  70.     osThreadAttr_t attr;
  72.     attr.name = "read";
  73.     attr.attr_bits = 0U;
  74.     attr.cb_mem = NULL;
  75.     attr.cb_size = 0U;
  76.     attr.stack_mem = NULL;
  77.     attr.stack_size = 1024 * 2;
  78.     attr.priority = 25;
  80.     // Create the Thread1 task
  81.     if (osThreadNew((osThreadFunc_t)uart_read, NULL, &attr) == NULL) {
  82.         printf("Failed to create read Thread!\n");
  83.     }
  84. }
  86. static void start_write_task() {
  87.     osThreadAttr_t attr;
  89.     attr.name = "write";
  90.     attr.attr_bits = 0U;
  91.     attr.cb_mem = NULL;
  92.     attr.cb_size = 0U;
  93.     attr.stack_mem = NULL;
  94.     attr.stack_size = 1024 * 2;
  95.     attr.priority = 25;
  97.     // Create the Thread1 task
  98.     if (osThreadNew((osThreadFunc_t)uart_write, NULL, &attr) == NULL) {
  99.         printf("Failed to create read Thread!\n");
  100.     }
  101. }
  103. static void uart(void)
  104. {
  105.     printf("Hello World!Hello genkipi\n");
  107.     //初始化GPIO口
  108.     IoTGpioInit(IOT_IO_NAME_11);
  109.     //设置IO口功能为GPIO
  110.     IoTGpioSetFunc(IOT_IO_NAME_11, IOT_GPIO_FUNC_GPIO_11_UART2_TXD);
  112.     IoTGpioInit(IOT_IO_NAME_12);
  113.     //设置IO口功能为GPIO
  114.     IoTGpioSetFunc(IOT_IO_NAME_12, IOT_GPIO_FUNC_GPIO_12_UART2_RXD);
  116.     IotUartAttribute attr;
  117.     attr.baudRate = 115200; //波特率
  118.     attr.dataBits = 8; //数据位
  119.     attr.stopBits = 1; // 停止位
  120.     attr.parity = IOT_UART_PARITY_NONE; //是否奇偶校验
  121.     attr.rxBlock = IOT_UART_BLOCK_STATE_NONE_BLOCK; // 是否为阻塞式
  122.     attr.txBlock = IOT_UART_BLOCK_STATE_NONE_BLOCK; // 是否为阻塞式
  123.     attr.pad = 0;//padding bit，占位空字符
  124.     IoTUartInit(IDX, &attr);
  126.     start_read_task();
  127.     start_write_task();
  128. }
  130. static void main(void)
  131. {
  132.     osThreadAttr_t attr;
  134.     attr.name = "uart";
  135.     attr.attr_bits = 0U;
  136.     attr.cb_mem = NULL;
  137.     attr.cb_size = 0U;
  138.     attr.stack_mem = NULL;
  139.     attr.stack_size = 1024;
  140.     attr.priority = 25;
  142.     // Create the Thread1 task
  143.     if (osThreadNew((osThreadFunc_t)uart, NULL, &attr) == NULL) {
  144.         printf("Failed to create say hello Thread!\n");
  145.     }
  146. }
  148. APP_FEATURE_INIT(main);
  1. static_library("uart——demo") {
  2.   sources = [ "main.c" ]
  4.   include_dirs = [
  5.         "//base/iothardware/peripheral/interfaces/inner_api",
  6.         "../../iot_hardware_hals/include"
  7.     ]
  8. }
  1. import("//build/lite/config/component/lite_component.gni")
  3. lite_component("app") {
  4.   features = [
  5.     "uart_demo"
  6.   ]
  7. }

校验方式

接线：
137.png
通过串口调试工具，测试两端是否联通。

练习题

  • 调试不同芯片间的串口