从设备的Android USB主机读取 [英] Android USB host read from device
问题描述
我试图得到一些数据输出连接到我的Android手机的USB设备上的主机模式。我能够将数据发送到它，但阅读失败。
I'm trying to get some data out of a USB device connected to my Android phone that is on host mode. I'm able to send data to it, but reading fails.
我已经看了几个的例子并尝试了所有我可以，但我没有在USB通信的经验，虽然现在我知道了一点点，我已经被困在这个时间越长，我愿意承认。
I've looked at several examples and tried all I could but I don't have any experience in USB communication, although by now I know a little, and I've been stuck on this longer that I care to admit.
我不是很熟悉的端点配置，但我知道的是，我的设备使用CDC类型的通信方法和两个输出（从手机到设备），输入注册。
I'm not very familiar with the endpoint configuration, but I know is that my device uses a CDC type communication method and both the output (from phone to device) and input are registered.
下面是管理与连接到手机的唯一设备的USB连接全班，它不以任何方式完成，但我想获得，阅读部分的工作之前，我再往前走。
Here's the whole class that manages the USB connection with the only device that is connected to the phone, it's not finished by any means, but I'd like to get that reading part to work before I go any further.
public class UsbCommunicationManager
{
static final String ACTION_USB_PERMISSION = "com.android.example.USB_PERMISSION";
UsbManager usbManager;
UsbDevice usbDevice;
UsbInterface intf = null;
UsbEndpoint input, output;
UsbDeviceConnection connection;
PendingIntent permissionIntent;
Context context;
byte[] readBytes = new byte[64];
public UsbCommunicationManager(Context context)
{
this.context = context;
usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
// ask permission from user to use the usb device
permissionIntent = PendingIntent.getBroadcast(context, 0, new Intent(ACTION_USB_PERMISSION), 0);
IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
context.registerReceiver(usbReceiver, filter);
}
public void connect()
{
// check if there's a connected usb device
if(usbManager.getDeviceList().isEmpty())
{
Log.d("trebla", "No connected devices");
return;
}
// get the first (only) connected device
usbDevice = usbManager.getDeviceList().values().iterator().next();
// user must approve of connection
usbManager.requestPermission(usbDevice, permissionIntent);
}
public void stop()
{
context.unregisterReceiver(usbReceiver);
}
public String send(String data)
{
if(usbDevice == null)
{
return "no usb device selected";
}
int sentBytes = 0;
if(!data.equals(""))
{
synchronized(this)
{
// send data to usb device
byte[] bytes = data.getBytes();
sentBytes = connection.bulkTransfer(output, bytes, bytes.length, 1000);
}
}
return Integer.toString(sentBytes);
}
public String read()
{
// reinitialize read value byte array
Arrays.fill(readBytes, (byte) 0);
// wait for some data from the mcu
int recvBytes = connection.bulkTransfer(input, readBytes, readBytes.length, 3000);
if(recvBytes > 0)
{
Log.d("trebla", "Got some data: " + new String(readBytes));
}
else
{
Log.d("trebla", "Did not get any data: " + recvBytes);
}
return Integer.toString(recvBytes);
}
public String listUsbDevices()
{
HashMap<String, UsbDevice> deviceList = usbManager.getDeviceList();
if(deviceList.size() == 0)
{
return "no usb devices found";
}
Iterator<UsbDevice> deviceIterator = deviceList.values().iterator();
String returnValue = "";
UsbInterface usbInterface;
while(deviceIterator.hasNext())
{
UsbDevice device = deviceIterator.next();
returnValue += "Name: " + device.getDeviceName();
returnValue += "\nID: " + device.getDeviceId();
returnValue += "\nProtocol: " + device.getDeviceProtocol();
returnValue += "\nClass: " + device.getDeviceClass();
returnValue += "\nSubclass: " + device.getDeviceSubclass();
returnValue += "\nProduct ID: " + device.getProductId();
returnValue += "\nVendor ID: " + device.getVendorId();
returnValue += "\nInterface count: " + device.getInterfaceCount();
for(int i = 0; i < device.getInterfaceCount(); i++)
{
usbInterface = device.getInterface(i);
returnValue += "\n Interface " + i;
returnValue += "\n\tInterface ID: " + usbInterface.getId();
returnValue += "\n\tClass: " + usbInterface.getInterfaceClass();
returnValue += "\n\tProtocol: " + usbInterface.getInterfaceProtocol();
returnValue += "\n\tSubclass: " + usbInterface.getInterfaceSubclass();
returnValue += "\n\tEndpoint count: " + usbInterface.getEndpointCount();
for(int j = 0; j < usbInterface.getEndpointCount(); j++)
{
returnValue += "\n\t Endpoint " + j;
returnValue += "\n\t\tAddress: " + usbInterface.getEndpoint(j).getAddress();
returnValue += "\n\t\tAttributes: " + usbInterface.getEndpoint(j).getAttributes();
returnValue += "\n\t\tDirection: " + usbInterface.getEndpoint(j).getDirection();
returnValue += "\n\t\tNumber: " + usbInterface.getEndpoint(j).getEndpointNumber();
returnValue += "\n\t\tInterval: " + usbInterface.getEndpoint(j).getInterval();
returnValue += "\n\t\tType: " + usbInterface.getEndpoint(j).getType();
returnValue += "\n\t\tMax packet size: " + usbInterface.getEndpoint(j).getMaxPacketSize();
}
}
}
return returnValue;
}
private void setupConnection()
{
// find the right interface
for(int i = 0; i < usbDevice.getInterfaceCount(); i++)
{
// communications device class (CDC) type device
if(usbDevice.getInterface(i).getInterfaceClass() == UsbConstants.USB_CLASS_CDC_DATA)
{
intf = usbDevice.getInterface(i);
// find the endpoints
for(int j = 0; j < intf.getEndpointCount(); j++)
{
if(intf.getEndpoint(j).getDirection() == UsbConstants.USB_DIR_OUT && intf.getEndpoint(j).getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)
{
// from android to device
output = intf.getEndpoint(j);
}
if(intf.getEndpoint(j).getDirection() == UsbConstants.USB_DIR_IN && intf.getEndpoint(j).getType() == UsbConstants.USB_ENDPOINT_XFER_BULK)
{
// from device to android
input = intf.getEndpoint(j);
}
}
}
}
}
private final BroadcastReceiver usbReceiver = new BroadcastReceiver()
{
public void onReceive(Context context, Intent intent)
{
String action = intent.getAction();
if(ACTION_USB_PERMISSION.equals(action))
{
// broadcast is like an interrupt and works asynchronously with the class, it must be synced just in case
synchronized(this)
{
if(intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false))
{
setupConnection();
connection = usbManager.openDevice(usbDevice);
connection.claimInterface(intf, true);
// set flow control to 8N1 at 9600 baud
int baudRate = 9600;
byte stopBitsByte = 1;
byte parityBitesByte = 0;
byte dataBits = 8;
byte[] msg = {
(byte) (baudRate & 0xff),
(byte) ((baudRate >> 8) & 0xff),
(byte) ((baudRate >> 16) & 0xff),
(byte) ((baudRate >> 24) & 0xff),
stopBitsByte,
parityBitesByte,
(byte) dataBits
};
connection.controlTransfer(UsbConstants.USB_TYPE_CLASS | 0x01, 0x20, 0, 0, msg, msg.length, 5000);
}
else
{
Log.d("trebla", "Permission denied for USB device");
}
}
}
else if(UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action))
{
Log.d("trebla", "USB device detached");
}
}
};
}
我不断收到 1 从阅读（）方法，这表明了某种错误，它总是倍出。也许问题来自于连接配置，我试过几个（阅读：试错），没有工作，令人惊讶的，我不需要任何配置将数据发送到设备
I keep getting -1 from the read() method which indicates some kind of error, it always times out. Maybe the problem comes from the connection configuration, I've tried several (read: trial and error) and none worked, surprisingly I don't need any configuration to send data to the device.
修改的
另外要注意的是，我使用的电缆微型USB微型USB和它只能以一种方式，那就是我的设备是由我的手机供电，只有当插头的连接手机和插头乙连接到设备，而不是其他方式......这似乎很奇怪。我是能够发送数据和接收不到时插入的正道的事实的存在。
It must also be noted that the cable I'm using is micro-USB to micro-USB and it only works in one way, that is my device is powered by my phone only when the plug A connected to phone and plug B connected to device, not the other way around... it seems very strange. The fact that I'm able to send data and not receive when plugged the right way remains.
编辑2 的
我发现，<一个href="http://www.basic4ppc.com/android/forum/threads/usb-to-arduino-only-working-in-one-direction.28569/"相对=nofollow>别人有，但他似乎并没有能够解决同样的问题。
I found that somebody else had the same problem but it seems he wasn't able to solve it.
编辑3 的
我终于找到<一个解决方案href="http://www.fourwalledcubicle.com/files/LUFA/Doc/120730/html/group___group___u_s_b_class_c_d_c_device.html"相对=nofollow>此页面：
另外一个主要的监督是没有机制主机通知设备，有在主机端准备接受数据的数据接收器。这意味着该装置可尝试发送数据，而主机没有侦听，导致冗长阻挡超时在传输例程。因此，人们强烈建议虚拟串行线DTR（数据终端就绪）信号尽可能使用，以确定是否一个主机应用程序准备好数据。
Another major oversight is that there is no mechanism for the host to notify the device that there is a data sink on the host side ready to accept data. This means that the device may try to send data while the host isn't listening, causing lengthy blocking timeouts in the transmission routines. It is thus highly recommended that the virtual serial line DTR (Data Terminal Ready) signal be used where possible to determine if a host application is ready for data.
所以，DTR信号是强制性的，所有我所要做的就是把它添加到接口配置：
So the DTR signal was mandatory and all I had to do was to add this to the interface configuration:
connection.controlTransfer(0x21, 0x22, 0x1, 0, null, 0, 0);
编辑4 的
如果有人有兴趣我完成了这个项目，它的开源并发表了关于我的GitHub的帐户。它不是稳定的所有的时间，虽然（见说明）和我不打算处理它了，但它的工作原理。随意使用它自己的项目。
If anybody is interested I finished the project and it's open source and published on my GitHub account. It's not stable all the time though (see the notes) and I don't plan working on it anymore, but it works. Feel free to use it for your own projects.
推荐答案
您可以使用来自的 https://github.com/mik3y/usb-serial-for-android
我的例子code：
UsbManager usbManager = null;
UsbDeviceConnection connection = null;
UsbSerialDriver driver = null;
UsbSerialPort port = null;
usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
List<UsbSerialDriver> availableDrivers = UsbSerialProber.getDefaultProber().findAllDrivers(manager);
// Open a connection to the first available driver.
for (UsbSerialDriver usd : availableDrivers) {
UsbDevice udv = usd.getDevice();
if (udv.getVendorId()==0x067B || udv.getProductId()==2303){
driver = usd;
break;
}
}
connection = usbManager.openDevice(driver.getDevice());
port = driver.getPorts().get(0);
driver.getDevice().
}
if (connection == null) return;
try{
port.open(connection);
port.setParameters(4800, UsbSerialPort.DATABITS_8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE);
try{
byte buffer[] = new byte[250];
//Log.d("GPS_REQ", "->");
int numBytesRead = port.read(buffer, 500); //5000;
}catch (Exception e) {
Log.d("GPS_ERR", e.getLocalizedMessage());
}
这篇关于从设备的Android USB主机读取的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
