一、需求描述:

        rk3568开发板运行OpenHarmony4.0,通过开发板上的uart串口与电脑进行通讯,相互收发字符串。

二、案例展示

        1、开发环境:

        (1)rk3568开发板

        (2)系统:OpenHarmony

        (3)电脑:Windows11笔记本,串口调试助手

        (4)Deveco Studio:evEco Studio 4.0 Release (4.0.0.600)

2、下载并运行开发案例

        下载开发案例,使用Deveco Studio打开运行编译、下载应用到rk3568开发板。开发板运行demo界面如下图所示。(.hap应用文件,见附件)

        (1)点击波特率选择按钮,选择相应的波特率;点击地址输入框,输入使用的串口的设备地址,这里以uart5(设备地址/dev/ttyS5)为例,选择波特率9600。  
 

        (2)将开发板通过串口转USB的转接线,将开发板与笔记本连接起来,电脑打开一个串口调试助手,如下图所示。

        (3)开发板点击“开启按钮”打开串口,然后点击“发送”按钮,想电脑通过串口发送输入框的字符串,电脑运行的串口调试助手接信息,并回显接收到的字符串;同理电脑通过串口调试助手想开发板发送字符串,开发板接收信息,并在回显框中回显接收到的字符串,如下图所示。

        (4)测试效果

OpenHarmony串口通讯展示

        注意:运行demo,应确保开发板的串口节点已被引出可用,且读写权限已被允许

三、应用开发流程

       该应用的开发,使用NAPI方式来编写使用串口的NAPI函数,通过这些函数,来对串口进行设置,打开,发送和接收数据(NAPI使用,详见NAPI篇)。在应用界面编写中,引用NAPI函数进行逻辑构建,完成应用开发。

         1、应用界面编写(Index.ets)



import BQNapi from 'libentry.so';//引入NAPI
import promptAction from '@ohos.promptAction';

const TAG = "uartToComputer"

@Entry
@Component
struct Index {
  @State isStart: boolean = false;
  private dateTime: Date = new Date();
  private scroller: Scroller = new Scroller()
  @State receiveMessage: string = '';
  @State sendMessage: string = 'https://www.bearkey.net/';
  @State currentUart: string = '';
  private UartPort: string = '/dev/ttyS5'
  private UartBand: string[] = ['9600', '19200', '38400', '57600', '115200']
  private UartBand_N: number[] = [9600, 19200, 38400, 57600, 115200]
  @State currentUartBandIndex: number = 0
  @State bandRate: number = 0;
  private fd: number = -1;
  private setIntervalID: number = -1;

  aboutToAppear() {

    // this.fd = BQNapi.open_port(this.currentUart, 115200);
    // console.log(TAG, `打开串口${this.currentUart},ret=${this.fd}`)
    this.setIntervalID = setInterval(() => {
      //判断是否有串口开启
      if (this.fd > 0) {
        //获取开启状态
        this.isStart = true
        //获取波特率
        this.bandRate = BQNapi.getBandRate(this.fd)
        let temp: string = BQNapi.series_receive_data(this.fd);
        if (temp === "-1") {
          console.log(TAG, '未接收到数据或接收失败');

        } else {
          this.dateTime = new Date();
          let year: number = this.dateTime.getFullYear(); //当前年
          let month = this.dateTime.getMonth() + 1;
          let date = this.dateTime.getDate();
          let hours = this.dateTime.getHours();
          let minutes = this.dateTime.getMinutes();
          let seconds = this.dateTime.getSeconds();
          let curryDateTime: string = year + '-' + month + '-' + date + ' ' + hours + ':' + minutes + ':' + seconds;
          temp = curryDateTime + '\n' + temp;
          this.receiveMessage = temp + this.receiveMessage
          this.scroller.scrollTo({ xOffset: 0, yOffset: 0 })
        }
      } else {
        this.isStart = false
        this.bandRate = 0;
        this.currentUart = '-'
      }
    }, 300)

  }

  aboutToDisappear() {
    console.log(TAG, `退出应用`)
    clearInterval(this.setIntervalID);
    if (this.fd > 0) {
      let e: number = BQNapi.close_port(this.fd);
      console.log(TAG, `关闭串口${this.currentUart},ret=${e}`)
      if (e == 0) {
        console.log(TAG, `关闭成功`)
      } else {
        console.log(TAG, `关闭失败`)
      }
    }
  }

  build() {
    Column() {
      Row() {
        Text('回显框')
          .fontSize(25)
          .size({ width: '50%', height: 30 })

        Button('清空窗口')
          .fontSize(30)
          .size({ width: 160, height: 40 })
          .onClick(() => {
            this.receiveMessage = '';
          });
      }
      .justifyContent(FlexAlign.SpaceAround)
      .margin({ top: 10, })
      .size({ width: '100%', height: 50 })

      Scroll(this.scroller) {
        Column() {
          Text(this.receiveMessage)
            .fontSize(20)
            .size({ width: '100%' })
            .constraintSize({ minHeight: 30 })
            .margin({ top: 10, bottom: 10 })
            .padding(10)
            .textAlign(TextAlign.Start)
        }.size({ width: '100%' })
        .constraintSize({ minHeight: 300 })
        .justifyContent(FlexAlign.Start)

      }.size({ width: '100%', height: 150 })
      .border({ width: 1, style: BorderStyle.Solid, radius: 10 })


      Row() {
        Text('输入框')
          .fontSize(25)
          .size({ width: '100%', height: 40 })
      }
      .justifyContent(FlexAlign.SpaceAround)
      .margin({ top: 10, })
      .size({ width: '100%', height: 50 })


      TextInput({ placeholder: "请输入需要发送的内容...", text: this.sendMessage })
        .fontSize(25)
        .size({ width: '100%', height: 50 })
        .border({ width: 1, style: BorderStyle.Solid, radius: 10 })
        .margin({ bottom: 10 })
        .onChange((value) => {
          this.sendMessage = value;
        })
      Row() {

        Button('发送')
          .fontSize(30)
          .enabled(this.isStart)
          .size({ width: 120, height: 40 })
          .onClick(() => {
            let a: number = BQNapi.series_send_data(this.sendMessage, this.fd)
            if (a === 0) {
              console.log(TAG, "发送成功!");
            } else {
              console.log(TAG, "发送失败!");
            }
          })
        Button('清空')
          .fontSize(30)
          .enabled(this.isStart)
          .size({ width: 120, height: 40 })
          .onClick(() => {
            this.sendMessage = '';
          })

      }
      .justifyContent(FlexAlign.SpaceAround)
      .margin({ top: 10, })
      .size({ width: '100%', height: 50 })

      Row() {
        Text('当前串口信息')
          .fontSize(25)
          .size({ width: '100%', height: 30 })

      }
      .justifyContent(FlexAlign.SpaceAround)
      .margin({ top: 10, })
      .size({ width: '100%', height: 50 })

      Column() {
        Row() {
          Text('波特率:')
            .fontSize(25)
            .size({ width: '40%', height: 30 })
            .textAlign(TextAlign.Center)
          Text(this.bandRate.toString())
            .fontSize(28)
            .size({ width: '60%', height: 30 })
            .textAlign(TextAlign.Center)

        }
        .justifyContent(FlexAlign.SpaceAround)
        .size({ width: '100%', height: 40 })

        Row() {
          Text('当前串口:')
            .fontSize(25)
            .size({ width: '40%', height: 30 })
            .textAlign(TextAlign.Center)
          Text(this.currentUart)
            .fontSize(28)
            .size({ width: '60%', height: 30 })
            .textAlign(TextAlign.Center)
        }
        .justifyContent(FlexAlign.SpaceAround)
        .size({ width: '100%', height: 40 })
      }
      .size({ width: '100%', height: 100 })
      .justifyContent(FlexAlign.SpaceAround)
      .border({ width: 1, style: BorderStyle.Solid, radius: 10 })


      Row() {

        Button(this.UartBand[this.currentUartBandIndex])
          .fontSize(25)
          .size({ width: '30%', height: 45 })
          .onClick(() => {
            this.showPickerDialogForUartBand()
          })
        TextInput({ placeholder: "请输入串口地址", text: this.UartPort })
          .fontSize(25)
          .border({ width: 1, style: BorderStyle.Solid, radius: 10 })
          .size({ width: '60%', height: 45 })
          .onChange((value) => {
            this.UartPort = value;
          })


      }
      .justifyContent(FlexAlign.SpaceAround)
      .margin({ top: 10, })
      .size({ width: '100%', height: 50 })

      Row() {
        Button("开启")
          .fontSize(35)
          .size({ width: '30%', height: 45 })
          .backgroundColor(this.isStart ? Color.Green : Color.Blue)
          .onClick(() => {
            if (this.isStart) {
              promptAction.showToast({
                message: "请先停止当前串口",
                duration: 500
              })
            } else {
              this.fd = BQNapi.open_port(this.UartPort, this.UartBand_N[this.currentUartBandIndex]);
              if (this.fd > 0) {
                console.log(TAG, `打开串口${this.currentUart},ret=${this.fd}`)
                this.currentUart = this.UartPort;
                promptAction.showToast({
                  message: "开启成功",
                  duration: 500
                })
              } else {
                promptAction.showToast({
                  message: "开启失败",
                  duration: 500
                })
              }
            }

          })
        Button('停止')
          .fontSize(35)
          .size({ width: '30%', height: 45 })
          .backgroundColor(this.isStart ? Color.Red : Color.Blue)
          .onClick(() => {
            if (this.isStart) {
              let e: number = BQNapi.close_port(this.fd);
              console.log(TAG, `关闭串口${this.currentUart},ret=${e}`)
              if (e == 0) {
                promptAction.showToast({
                  message: "关闭成功",
                  duration: 500
                })
                this.fd = -1;
                this.currentUart = '...'
                console.log(TAG, `关闭成功`)
              } else {
                console.log(TAG, `关闭失败`)
                promptAction.showToast({
                  message: "关闭失败",
                  duration: 500
                })
              }
            } else {
              promptAction.showToast({
                message: "未启用串口",
                duration: 500
              })
            }

          })
      }
      .justifyContent(FlexAlign.SpaceAround)
      .margin({ top: 20, })
      .size({ width: '100%', height: 50 })

    }
    .size({ width: '100%', height: '100%' })
    .padding(10)
    .justifyContent(FlexAlign.Start)
    .alignItems(HorizontalAlign.Center)
  }

  showPickerDialogForUartBand() {
    TextPickerDialog.show({
      range: this.UartBand,
      selected: this.currentUartBandIndex,
      disappearTextStyle: { color: Color.Red, font: { size: 15, weight: FontWeight.Lighter } },
      textStyle: { color: Color.Black, font: { size: 20, weight: FontWeight.Normal } },
      selectedTextStyle: { color: Color.Blue, font: { size: 30, weight: FontWeight.Bolder } },
      onAccept: (value: TextPickerResult) => {
        let temp = value.value as string
        this.currentUartBandIndex = value.index as number

      },
      onCancel: () => {
        console.info(TAG, "TextPickerDialog:onCancel()")
      },
      onChange: (value: TextPickerResult) => {
        console.info(TAG, "TextPickerDialog:onChange()" + JSON.stringify(value))
      }
    })
  }
}

        2、NAPI函数引出声明(index.d.ts)

export const open_port: (port_address: string, band_rate: number) => number; //打开串口,打开成功返回描述符(int),失败-1

export const close_port: (serial_port: number) => number; //关闭串口,关闭成功返回0,失败则返回-1.

export const series_send_data: (tx_data: string, serial_port: number) => number; //发送数据

export const series_receive_data: (serial_port: number) => string; //接收数据,成功返回接收字符串,失败返回-1

export const getBandRate: (serial_port: number) => number; //查询波特率,成功返回波特率,失败返回-1

        3、完整应用工程源码,私信

声明:非本人允许,严禁转载,演示开发板为厦门贝启科技的BQ3568HM产品

(1)首页-贝启科技官方企业店-淘宝网

(2)厦门贝启科技有限公司-Bearkey-官网

点赞(0) 打赏

评论列表 共有 0 条评论

暂无评论

微信公众账号

微信扫一扫加关注

发表
评论
返回
顶部