UsbSerial

Usb serial controller for Android. For more information, there is a more complete description.

Devices Supported

CP210X devices Default: 9600,8,1,None,flow off

CDC devices Default 115200,8,1,None,flow off

FTDI devices Default: 9600,8,1,None,flow off

PL2303 devices Default 9600,8,1,None,flow off

CH34x devices Default 9600,8,1,None,flow off

How to use it?

Instantiate a new object of the UsbSerialDevice class

UsbDevice device;
UsbDeviceConnection usbConnection;
...
UsbSerialDevice serial = UsbSerialDevice.createUsbSerialDevice(device, usbConnection); 

Open the device and set it up as desired

serial.open();
serial.setBaudRate(115200);
serial.setDataBits(UsbSerialInterface.DATA_BITS_8);
serial.setParity(UsbSerialInterface.PARITY_ODD);
serial.setFlowControl(UsbSerialInterface.FLOW_CONTROL_OFF); 

If flow control is needed (currently only supported in CP201x and FTDI devices)

/**
Values:
    UsbSerialInterface.FLOW_CONTROL_OFF
    UsbSerialInterface.FLOW_CONTROL_RTS_CTS 
    UsbSerialInterface.FLOW_CONTROL_DSR_DTR
**/
serial.setFlowControl(UsbSerialInterface.FLOW_CONTROL_RTS_CTS);

There is no need to be polling if you want to perform a bulk transaction to a IN endpoint. Define a simply callback

private UsbSerialInterface.UsbReadCallback mCallback = new UsbSerialInterface.UsbReadCallback() {

		@Override
		public void onReceivedData(byte[] arg0) 
		{
			// Code here :)
		}
		
};

And pass a reference of it

serial.read(mCallback);

Changes in the CTS and DSR lines will be received in the same manner. Define a callback and pass a reference of it.

private UsbSerialInterface.UsbCTSCallback ctsCallback = new UsbSerialInterface.UsbCTSCallback() {
        @Override
        public void onCTSChanged(boolean state) {
           // Code here :)
        }
    };
    
private UsbSerialInterface.UsbDSRCallback dsrCallback = new UsbSerialInterface.UsbDSRCallback() {
        @Override
        public void onDSRChanged(boolean state) {
           // Code here :)
        }
    };
    
serial.getCTS(ctsCallback);
//serial.getDSR(dsrCallback);

Write something

serial.write("DATA".getBytes()); // Async-like operation now! :)

Raise the state of the RTS or DTR lines

serial.setRTS(true); // Raised
serial.setRTS(false); // Not Raised
serial.setDTR(true); // Raised
serial.setDTR(false); // Not Raised

Close the device:

serial.close();

I recommend using UsbSerial as shown above but if you want to perform write and read operations in synchronous way it is possible using these methods:

public boolean syncOpen();
public int syncWrite(byte[] buffer, int timeout)
public int syncRead(byte[] buffer, int timeout)
public void syncClose();

In Android usb api, when a usb device has been close it must be reopened

UsbDevice device;
...
UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);
manager.openDevice(UsbDevice device)

Gradle

Add the jitpack repo to your your project's build.gradle at the end of repositories

/build.gradle

allprojects {
	repositories {
		jcenter()
		maven { url "https://jitpack.io" }
	}
}

Then add the dependency to your module's build.gradle:

/app/build.gradle

compile 'com.github.felHR85:UsbSerial:4.1'

TO-DO

• RTS/CTS and DSR/DTR implementations for PL2303, CDC and CH430/431