OTG 340/341开发U转232

痛定思痛。 2022-07-15 08:40 118阅读 0赞

由于项目需要，最近用CH340芯片做了一款Android设备上的OTG产品，技术含量不大，但是为了以后查阅方便，同时希望帮助其他人，现总结如下，想到哪里就写到哪里，请大家勿怪。

注意：

1、Android系统版本必须是3.1以上，3.1版本及以上才支持USB HOST协议；

2、Android设备如手机、平板等的Micro-USB的ID是悬空的，所以OTG的从设备的ID必须接地；

3、打开OTG设备之前，必须先允许设备，否则会产生运行时错误；

4、先打开OTG设备，在进行串口配置；切更改串口配置时候，不需要close->open->config流程，直接config即可；

5、官方驱动下载地址：[http://download.csdn.net/detail/wuhenyouyuyouyu/9678373][http_download.csdn.net_detail_wuhenyouyuyouyu_9678373]

该驱动包包括：1、驱动库； 2、驱动库说明； 3、官方DEMO源码，Android studio v2.2.2版本； 4、一款官方APP调试工具；

一、添加官方驱动包CH34xUARTDriver.jar

1、把官方驱动包拷贝到：xxx\\app\\libs；

2、把驱动包加入到工程中：

![20161110095123731][]

![20161110095144165][]

![20161110095156169][]

二、添加xml文件

1、新建xml资源文件夹：

res->右键 new->Android resource directory

![20161110095225743][]

![20161110095234837][]

选择xml,点击OK。

2、将device\_filter.xml文件拷贝到：xxx\\app\\src\\main\\res\\xml\\内；

![20161110095251873][]

三、修改Mainfest.xml文件

1、添加：

**  
<**uses-feature android:name="android.hardware.usb.host"** />  
<**uses-sdk  
android:minSdkVersion="12"  
android:targetSdkVersion="19"** />

2、在activity属性内添加

<intent-filter>
        <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
    </intent-filter>
    
    <meta-data android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
        android:resource="@xml/device_filter" />

四、判断设备是否支持USB HOST

public boolean myOTG_CheckHOST(final Activity activity,boolean   isShow) {
        if (!MyOTGApplication.driver.UsbFeatureSupported())// 判断系统是否支持USB HOST
        {
            if(isShow) {
                Dialog dialog = new AlertDialog.Builder(activity)
    
                        .setTitle("提示")
                        .setMessage("您的手机不支持USB HOST，请更换其他手机再试！")
                        .setPositiveButton("确认",
                                new DialogInterface.OnClickListener() {
    
                                    @Override
                                    public void onClick(DialogInterface arg0,
                                                        int arg1) {
                                        System.exit(0);
                                    }
                                }).create();
                dialog.setCanceledOnTouchOutside(false);
                dialog.show();
            }
            return  false;
        }
        //activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);// 保持常亮的屏幕的状态
        return  true;
    }

五、打开设备

private boolean  myOTG_Open(final Activity activity,boolean   isShow){
    
        if (!MyOTGApplication.driver.ResumeUsbList())// ResumeUsbList方法用于枚举CH34X设备以及打开相关设备
        {
            if(isShow) {
                Toast.makeText(activity, "打开设备失败!",
                        Toast.LENGTH_SHORT).show();
            }
            MyOTGApplication.driver.CloseDevice();
            return false;
        } else {
            if (!MyOTGApplication.driver.UartInit()) {
      //对串口设备进行初始化操作
                if(isShow) {
                    Toast.makeText(activity, "设备初始化失败!",
                            Toast.LENGTH_SHORT).show();
                    Toast.makeText(activity, "打开" +
                                    "设备失败!",
                            Toast.LENGTH_SHORT).show();
                }
                return  false;
            }
            if(isShow) {
                Toast.makeText(activity, "打开设备成功!",
                        Toast.LENGTH_SHORT).show();
            }
            isOpen = true;
            new readThread().start();//开启读线程读取串口接收的数据
            return true;
        }
    }

六、配置

//配置串口,先打开OTG，再配置串口;
    //重新配置串口时候，不需要Close->open->config，直接Config即可
    private boolean  myOTG_SetConfig(final Activity activity,boolean   isShow){
        if (MyOTGApplication.driver.SetConfig(baudRate, dataBit, stopBit, parity, flowControl)) {
      //配置串口波特率，函数说明可参照编程手册
            if(isShow) {
                Toast.makeText(activity, "串口设置成功!",
                        Toast.LENGTH_SHORT).show();
            }
            return  true;
        } else {
            if(isShow) {
                Toast.makeText(activity, "串口设置失败!",
                        Toast.LENGTH_SHORT).show();
            }
            return false;
        }
    }

七、关闭

public void myOTG_Close(){
        isOpen = false;
        MyOTGApplication.driver.CloseDevice();
        myMath.showToast(myOTG_activity,"串口关闭成功！",200);
    }

八、读

private class readThread extends Thread {
    
        public void run() {
    
            byte[] buffer = new byte[64];
            int length =0;
            while (true) {
                Message msg = Message.obtain();
                if (!isOpen) {
                    break;
                }
                length = MyOTGApplication.driver.ReadData(buffer, 64);
                if (length > 0) {
                    //String recv = myMath.toHexString(buffer, length);
                    msg.what=3;//OTG接收线程
                    msg.arg1=length;
                    msg.obj = buffer;
                    OTGHandler.sendMessage(msg);
                    length=0;
                }
            }
        }
    }

九、写

public boolean  myOTG_writeBuffer(byte[] to_send){
        //byte[] to_send = toByteArray(writeText.getText().toString());
        if(null != writeData){
      //正在发送，请等待
            return false;
        }
        int retval = MyOTGApplication.driver.WriteData(to_send, to_send.length);//写数据，第一个参数为需要发送的字节数组，第二个参数为需要发送的字节长度，返回实际发送的字节长度
        if (retval < 0) {
            return false;
        }
        return true;
    }

十、注册USB消息，并监听USB设备插拔

public void startListen(Context context)    //USB枚举消息注册函数
    {
        IntentFilter usbDeviceStateFilter = new IntentFilter();
        usbDeviceStateFilter.addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED);
        usbDeviceStateFilter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);
        context.registerReceiver(mUsbReceiver, usbDeviceStateFilter);
    }
    
    /***********************************************************************
     * 问题：
     * 1、收到OTG插拔消息后，应该进行PID和VID检查，在进行操作；
     * 2、
     **********************************************************************/
    private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
    
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action)) {
                UsbDevice device = (UsbDevice)intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
                if (device != null) {
                    // call your method that cleans up and closes communication with the device
                    if(isOpen){
                        myOTG_Close();
                    }
                }
            }else{
                if(UsbManager.ACTION_USB_DEVICE_ATTACHED.equals(action)){
                    UsbDevice device = (UsbDevice)intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
                    if (device != null) {
                        // call your method that cleans up and closes communication with the device
                        if(!isOpen){
                            myOTG_Open(true);
                        }
                    }
                }
            }
        }
    };

十一、读取XML文件

private boolean    UsbDeviceFilter(DeviceFilter    inDevice) throws XmlPullParserException,
            IOException {
        Resources   myResources =   myOTG_activity.getResources();
        XmlResourceParser   parser = myResources.getXml(R.xml.device_filter);
        int eventType = parser.getEventType();  // 获取事件类型
        while (eventType != XmlPullParser.END_DOCUMENT) {
            String tagName = parser.getName();
            if ("usb-device".equals(tagName)
                    && parser.getEventType() == XmlPullParser.START_TAG) {
                    DeviceFilter findDevice = new DeviceFilter(-1,-1,-1,-1,-1);
                    findDevice.readXML(parser);
                    if(        (inDevice.mVendorId == findDevice.mVendorId)
                            && (inDevice.mProductId == findDevice.mProductId)
                            && (inDevice.mVendorId != -1)){
                        return true;
                    }
            }
            eventType = parser.next();
        }
        return false;
    }

[http_download.csdn.net_detail_wuhenyouyuyouyu_9678373]: http://download.csdn.net/detail/wuhenyouyuyouyu/9678373
[20161110095123731]: /images/20220715/9c4919ab1ba4467080adcb34dd5d8564.png
[20161110095144165]: /images/20220715/7add19d9f9f241c3b74642d62077fe6a.png
[20161110095156169]: /images/20220715/c7a6a2ff1aab4d18926bde5d40ad70bd.png
[20161110095225743]: /images/20220715/2d1e7dc5388a4a6c84c66fe8649d2e91.png
[20161110095234837]: /images/20220715/1c3fefe09fcf4032b91be58318906dd5.png
[20161110095251873]: /images/20220715/50eb26e1cdd64557b9698230012e979d.png