Android USB 无法通过 bulkTransfer 读取完整数据

Question

我正在使用 Android USB 主机 API 通过 FT232 发送和接收数据。我正在为发送部分和阅读部分使用两个线程。我可以发送和接收数据，但读取的数据不等于发送的数据。例如，当我发送字节 [1、2、3、4、5] 时。读取的数据有时是byte[1, 2, 5]。有时可以读取 5 个字节，但有时会丢失一些字节。附件是我正在使用的代码。

设置部分：

HashMap<String, UsbDevice> list = mUsbManager.getDeviceList();
Iterator<UsbDevice> iterator = list.values().iterator();
while(iterator.hasNext()) {
    UsbDevice device = iterator.next();
    if (device.getInterfaceCount() == 1) {
        mInterface = device.getInterface(0);
        for (int i = 0; i < mInterface.getEndpointCount(); i++) {
            if (mInterface.getEndpoint(i).getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
                if (mInterface.getEndpoint(i).getDirection() == UsbConstants.USB_DIR_IN) {
                    mEndpointIn = mInterface.getEndpoint(i);
                } else {
                    mEndpointOut = mInterface.getEndpoint(i);
                }
             }
                            }
                    }
                }
            }
        }

发送部分：

UsbDeviceConnection connection = mUsbManager.openDevice(device);
if (connection == null) {
    Log.e(TAG, "Connection terminated");
    return;
}
byte[] bytes = new byte[1, 2, 3, 4, 5];
boolean claimed = connection.claimInterface(mInterface, true);
if (claimed) {
    connection.controlTransfer(0x40, 0x03, 0x0034, 0, null, 0, 0); // baud rate 57600
    connection.controlTransfer(0x40, 0x04, 0x0008, 0, null, 0, 0); // 8-N-1
    int sentLength = connection.bulkTransfer(mEndpointOut, bytes, bytes.length, 100);
    connection.releaseInterface(mInterface);
    connection.close();
}

阅读部分：

UsbDeviceConnection connection = mUsbManager.openDevice(device);
if (connection == null) {
    Log.e(TAG, "Connection terminated");
    return;
}
byte[] inData = new byte[64];
boolean claimed = connection.claimInterface(mInterface, true);
if (claimed) {
    connection.controlTransfer(0x40, 0x03, 0x0034, 0, null, 0, 0); // baud rate 57600
    connection.controlTransfer(0x40, 0x04, 0x0008, 0, null, 0, 0); // 8-N-1
    int readLength = connection.bulkTransfer(mEndpointIn, inData, inData.length, 100);
    connection.releaseInterface(mInterface);
    connection.close();
    // 'result' is the data I want, the first 2 bytes are status bytes so being removed
    byte[] result = new byte[inData.length - 2];
    System.arrayCopy(inData, 2, result, 0, inData.length - 2);
}

Answer 1

我找到了 Android 的库，它解决了这个问题。希望对遇到同样问题的人有所帮助。

UsbSerial

Android USB 无法通过 bulkTransfer 读取完整数据

Android USB cannot read complete data through bulkTransfer

android

usb

usbserial

ftdi