Awesome
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 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' }
}
}
Starting with gradle 6.8 you can alternatively add jitpack.io repository to your settings.gradle:
dependencyResolutionManagement {
repositories {
...
maven { url 'https://jitpack.io' }
}
}
If using gradle kotlin use line
maven(url = "https://jitpack.io")
Add library to dependencies
dependencies {
implementation 'com.github.mik3y:usb-serial-for-android:3.8.0'
}
2. If the app should be notified when a device is attached, add
device_filter.xml
to your project's res/xml/
directory and configure in your AndroidManifest.xml
.
<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>
3. Use it! Example code snippet:
open device:
// 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) {
// add UsbManager.requestPermission(driver.getDevice(), ..) handling here
return;
}
UsbSerialPort port = driver.getPorts().get(0); // Most devices have just one port (port 0)
port.open(connection);
port.setParameters(115200, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE);
then use direct read/write
port.write(request, WRITE_WAIT_MILLIS);
len = port.read(response, READ_WAIT_MILLIS);
or direct write + event driven read:
usbIoManager = new SerialInputOutputManager(usbSerialPort, this);
usbIoManager.start();
...
port.write("hello".getBytes(), WRITE_WAIT_MILLIS);
@Override
public void onNewData(byte[] data) {
runOnUiThread(() -> { textView.append(new String(data)); });
}
and finally:
port.close();
For a simple example, see UsbSerialExamples folder in this project.
See separate github project SimpleUsbTerminal for a more complete example with:
- Background service to stay connected while the app is not visible or rotating
- Flow control
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 USB interface types and 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 FTDI device, which use VID 0x1234 and PID 0x0001 and 0x0002.
ProbeTable customTable = new ProbeTable();
customTable.addProduct(0x1234, 0x0001, FtdiSerialDriver.class);
customTable.addProduct(0x1234, 0x0002, FtdiSerialDriver.class);
UsbSerialProber prober = new UsbSerialProber(customTable);
List<UsbSerialDriver> drivers = prober.findAllDrivers(usbManager);
// ...
Note: as of v3.5.0 this library detects CDC devices by USB interface types instead of fixed VID+PID, so custom probers are typically not required any more for CDC devices.
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 FT232R, FT232H, FT2232H, FT4232H, FT230X, FT231X, FT234XD
- Prolific PL2303
- Silabs CP2102, CP210*
- Qinheng CH340, CH341A, CH9102
devices implementing the CDC/ACM protocol like
- Arduino using ATmega32U4
- Digispark using V-USB software USB
- BBC micro:bit using ARM mbed DAPLink firmware
- ...
and some device specific drivers:
- GsmModem devices, e.g. for Unisoc based Fibocom GSM modems
- Chrome OS CCD (Closed Case Debugging)
Help & Discussion
For common problems, see the FAQ wiki page.
Are you using the library? Add your project to ProjectsUsingUsbSerialForAndroid.