我发现了一个关于读取 FTDI 设备的 USB 数据的问题。 Transferring data USB 我将此代码用于多产设备，并且可以检测到 USB 等，除了 conn.bulkTransfer() 给出 -1。

    private class UsbRunnable implements Runnable {
    private final UsbDevice mDevice;

    UsbRunnable(UsbDevice dev) {
        mDevice = dev;
    }


    public void run() {//here the main USB functionality is implemented
        UsbDeviceConnection conn = mUsbManager.openDevice(mDevice);
        if (!conn.claimInterface(mDevice.getInterface(1), true)) {
            l("in run(), no connection");
            return;
        }
        l("in run(), connection");



         conn.controlTransfer(0x40, 0, 0, 0, null, 0, 0);// reset
         // mConnection.controlTransfer(0×40,
         // 0, 1, 0, null, 0,
         // 0);//clear Rx
         conn.controlTransfer(0x40, 0, 2, 0, null, 0, 0);// clear Tx
         conn.controlTransfer(0x40, 0x02, 0x0000, 0, null, 0, 0);// flow
                 // control
                 // none
         conn.controlTransfer(0x40, 0x03,  0xC04E, 0, null, 0, 0);// baudrate
                 // 38400
         conn.controlTransfer(0x40, 0x04, 0x0008, 0, null, 0, 0);// data bit
                 // 8, parity
                 // none,
                 // stop bit
                 // 1, tx off   




        UsbEndpoint epIN = null;
        UsbEndpoint epOUT = null;

        byte counter=0;
    //conn.bulkTransfer(epOUT, new byte[]{msData}, 1, 0);

        UsbInterface usbIf = mDevice.getInterface(0);
        for (int i = 0; i < usbIf.getEndpointCount(); i++) {
            l("EP: "
                    + String.format("0x%02X", usbIf.getEndpoint(i)
                            .getAddress()));
            l("Type:"+usbIf.getEndpoint(i).getType());
            if (usbIf.getEndpoint(i).getType() == UsbConstants.USB_ENDPOINT_XFER_INT) {
                l("Bulk Endpoint");
                l("direction: "+usbIf.getEndpoint(i).getDirection());
                if (usbIf.getEndpoint(i).getDirection() == UsbConstants.USB_DIR_IN)
                    epIN = usbIf.getEndpoint(i);

            }
            else l("no bulk");
            l("epIN: "+epIN.toString());
        }

        for (;;) {// this is the main loop for transferring
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            // This is where it is meant to receive
            byte[] buffer = new byte[38400];

            StringBuilder str = new StringBuilder();

            l("bulk transfer thing: " + conn.bulkTransfer(epIN, buffer, 38400, 1000));

            if (conn.bulkTransfer(epIN, buffer, 38400, 1000) > 0 ) {
                l("bulk transfer is success");
                for (int i = 2; i < 64; i++) {
                    if (buffer[i] != 0) {
                        str.append((char) buffer[i]);
                    } else {
                        l(str);
                        break;
                    }
                }

            }
            // this shows the complete string
            l(str);


            if (mStop) {
                mConnectionHandler.onUsbStopped();
                return;
            }
             l("sent " + counter);
                counter++;
                counter = (byte) (counter % 16);
        }

    }
}

// END MAIN LOOP
private BroadcastReceiver mPermissionReceiver = new PermissionReceiver(
        new IPermissionListener() {

            public void onPermissionDenied(UsbDevice d) {
                l("Permission denied on " + d.getDeviceId());
            }
        });

private static interface IPermissionListener {
    void onPermissionDenied(UsbDevice d);
}

public final static String TAG = "USBController";

private void l(Object msg) {
    Log.d(TAG, ">==< " + msg.toString() + " >==<");
}

private void e(Object msg) {
    Log.e(TAG, ">==< " + msg.toString() + " >==<");
}

谁能告诉我需要做哪些更改？提前谢谢你。

最佳答案

有几个问题。

我认为注释掉的行是您遇到问题的地方。您可能需要重新格式化代码缩进并提供更多信息。无论如何，假设您的问题发生在这里:

byte counter=0;
//conn.bulkTransfer(epOUT, new byte[]{msData}, 1, 0);

我看到的直接问题 - epOut，您要向其发送数据的端点为空。所以当然会失败。您正在向空发送数据。我点击了您发布到您复制的示例代码的链接，他们有一行显示:

epOUT = usbIf.getEndpoint(i);

我强烈建议至少，在开始进行更改之前，您首先要确保您了解原始代码或让它在您自己的程序中运行。 不要只需复制上面的代码行即可“解决”您的问题。

关于android - 从 USB(多产)到 Android 设备的数据传输，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/13108484/