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usb-serial-for-android

This is a driver library for communication with Arduinos and other USB serial hardware on Android, using the Android USB Host Mode (OTG) available since Android 3.1 and working reliably since Android 4.2.

No root access, ADK, or special kernel drivers are required; all drivers are implemented in Java. You get a raw serial port with read(), write(), and other basic functions for use with your own protocols.

Quick Start

1. Add library to your project:

Add jitpack.io repository to your root build.gradle:

allprojects {
    repositories {
        ...
        maven { url 'https://jitpack.io' }
    }
}

Add library to dependencies

dependencies {
    implementation 'com.github.mik3y:usb-serial-for-android:Tag'
}

2. Copy device_filter.xml to your project's res/xml/ directory.

3. Configure your AndroidManifest.xml to notify your app when a device is attached (see Android USB Host documentation for help).

<activity
    android:name="..."
    ...>
  <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" />
</activity>

4. Use it! Example code snippet:

// Find all available drivers from attached devices.
UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);
List<UsbSerialDriver> availableDrivers = UsbSerialProber.getDefaultProber().findAllDrivers(manager);
if (availableDrivers.isEmpty()) {
  return;
}

// Open a connection to the first available driver.
UsbSerialDriver driver = availableDrivers.get(0);
UsbDeviceConnection connection = manager.openDevice(driver.getDevice());
if (connection == null) {
  // You probably need to call UsbManager.requestPermission(driver.getDevice(), ..)
  return;
}

// Read some data! Most have just one port (port 0).
UsbSerialPort port = driver.getPorts().get(0);
try {
  port.open(connection);
  port.setParameters(115200, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE);

  byte buffer[] = new byte[16];
  int numBytesRead = port.read(buffer, 1000);
  Log.d(TAG, "Read " + numBytesRead + " bytes.");
} catch (IOException e) {
  // Deal with error.
} finally {
  port.close();
}

For a simple example, see the UsbSerialExamples project in git, which is a simple application for reading and showing serial data.

For a more complete example, see separate github project SimpleUsbTerminal

A simple Arduino application is also available which can be used for testing.

Probing for Unrecognized Devices

Sometimes you may need to do a little extra work to support devices which usb-serial-for-android doesn't (yet) know about -- but which you know to be compatible with one of the built-in drivers. This may be the case for a brand new device or for one using a custom VID/PID pair.

UsbSerialProber is a class to help you find and instantiate compatible UsbSerialDrivers from the tree of connected UsbDevices. Normally, you will use the default prober returned by UsbSerialProber.getDefaultProber(), which uses the built-in list of well-known VIDs and PIDs that are supported by our drivers.

To use your own set of rules, create and use a custom prober:

// Probe for our custom CDC devices, which use VID 0x1234
// and PIDS 0x0001 and 0x0002.
ProbeTable customTable = new ProbeTable();
customTable.addProduct(0x1234, 0x0001, CdcAcmSerialDriver.class);
customTable.addProduct(0x1234, 0x0002, CdcAcmSerialDriver.class);

UsbSerialProber prober = new UsbSerialProber(customTable);
List<UsbSerialDriver> drivers = prober.findAllDrivers(usbManager);
// ...

Of course, nothing requires you to use UsbSerialProber at all: you can instantiate driver classes directly if you know what you're doing; just supply a compatible UsbDevice.

Compatible Devices

This library supports USB to serial converter chips:

FTDI FT232, FT2232, ...
Prolific PL2303
Silabs CP2102, CP2105, ...
Qinheng CH340

and devices implementing the CDC/ACM protocol like

Arduino using ATmega32U4
Digispark using V-USB software USB
BBC micro:bit using ARM mbed DAPLink firmware
...

Author, License, and Copyright

usb-serial-for-android is written and maintained by mike wakerly and kai morich

This library is licensed under LGPL Version 2.1. Please see LICENSE.txt for the complete license.

Portions of this library are based on libftdi. Please see FtdiSerialDriver.java for more information.

Help & Discussion

For common problems, see the Troubleshooting wiki page.

Are you using the library? Let us know on the group and we'll add your project to ProjectsUsingUsbSerialForAndroid.

5.5 KiB Czysty Wina Historia