Seeeduino XIAO as USB device (TinyUSB)

This wiki introduces how to use Seeeduino XIAO as USB-Client with the help of TinyUSB library. It allows XIAO to be used for HID devices such as keyboard, mouse and etc.

This functionality is dependent on Adafruit TinyUSB Library for Arduino. The library has been tested with Seeeduino XIAO and Wio Terminal(SAMD51) and working properly.

Installing the Adafruit TinyUSB Library for Arduino

  1. Visit the Adafruit TinyUSB Library for Arduino repositories and download the entire repo to your local drive.

  2. Now, the library can be installed to the Arduino IDE. Open the Arduino IDE, and click sketch -> Include Library -> Add .ZIP Library, and choose the Adafruit_TinyUSB_Arduino file that you've have just downloaded.


Simple Example Code

There are many examples provided by the TinyUSB library, here we can navigate to Files -> Examples -> Adafruit TinyUSB Library -> HID -> hid_mouse for a simple mouse example. Connect a button to D0 pin of XIAO and also configure in the code(#28), as followed:


Make sure you have updated the ArduinoCore-samd to the latest versions to avoid compile error.

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 MIT license, check LICENSE for more information
 Copyright (c) 2019 Ha Thach for Adafruit Industries
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 any redistribution

#include "Adafruit_TinyUSB.h"

/* This sketch demonstrates USB HID mouse
 * Press button pin will move
 * - mouse toward bottom right of monitor
 * Depending on the board, the button pin
 * and its active state (when pressed) are different
  const int pin = 4; // Left Button
  bool activeState = true;
#elif defined ARDUINO_NRF52840_FEATHER
  const int pin = 7; // UserSw
  bool activeState = false;
  const int pin = 0;
  bool activeState = true;

// HID report descriptor using TinyUSB's template
// Single Report (no ID) descriptor
uint8_t const desc_hid_report[] =

// USB HID object
Adafruit_USBD_HID usb_hid;

// the setup function runs once when you press reset or power the board
void setup()
  // Set up button, pullup opposite to active state
  pinMode(pin, activeState ? INPUT_PULLDOWN : INPUT_PULLUP);

  usb_hid.setReportDescriptor(desc_hid_report, sizeof(desc_hid_report));



  // wait until device mounted
  while( !USBDevice.mounted() ) delay(1);

  Serial.println("Adafruit TinyUSB HID Mouse example");

void loop()
  // poll gpio once each 10 ms

  // Whether button is pressed
  bool btn_pressed = (digitalRead(pin) == activeState);

  // nothing to do if button is not pressed
  if (!btn_pressed) return;

  // Remote wakeup
  if ( USBDevice.suspended() )
    // Wake up host if we are in suspend mode
    // and REMOTE_WAKEUP feature is enabled by host

  if ( usb_hid.ready() )
    int8_t const delta = 5;
    usb_hid.mouseMove(0, delta, delta); // no ID: right + down