usb-dev

Introduction

The goal of this repository is twofold: first, to document the steps required to set up Ubuntu 20.04 LTS in order to develop user space C programs to perform I/O on USB devices; and secondly, to demonstrate complete programs that actually work. My test USB device is a Microsoft Xbox Wireless Controller (model 1708), which is connected to my Linux machine with a micro USB cable.

Prerequisites

These programs were developed and tested on Ubuntu 20.04 LTS.
Superuser privilege is required.

Install libusb development files

$ sudo apt install libusb-1.0-0-dev
$ sudo updatedb && locate libusb.h

I'm using libusb version 1.0.23, which was released on 29 August 2019. To find out the version that you installed, use this command:

$ dpkg -s libusb-1.0-0-dev

Create udev rule

Connect your Xbox controller to any of your computer's USB port. Then use the lsusb command to find out its vendor ID and product ID. Create a new udev rules file for your controller:

$ sudo nano /etc/udev/rules.d/40-microsoft.xbox.controller.rules

Here's the content of /etc/udev/rules.d/40-microsoft.xbox.controller.rules:

# Microsoft Xbox controller
ATTRS{idVendor}=="045e", ATTRS{idProduct}=="02ea", MODE="664", GROUP="plugdev"

Reload the rules files on your Linux system:

$ sudo udevadm control --reload

Finally, disconnect and then reconnect your controller.

Without this udev rule, the libusb_open_device_with_vid_pid() function call in gamepad.c will fail:

libusb v1.0.23.11397 (http://libusb.info)
libusb: error [_get_usbfs_fd] libusb couldn't open USB device /dev/bus/usb/001/004: Permission denied
libusb: error [_get_usbfs_fd] libusb requires write access to USB device nodes.
Cannot open device

Build programs

$ make

Usage

Type ./gamepad and play with the buttons on your controller. You should see some text output. To activate rumble, press the A button. To exit the program, press the X button. Below is a sample run of the program when both the A button and the X button are pressed at the same time:

libusb v1.0.23.11397 (http://libusb.info)
Device opened
Port path: 1
libusb_set_auto_detach_kernel_driver() returned 0
Claimed interface
Read successful! 18 bytes: 2000270E5000000000002FFDF8FE2DFE8FF3
  type: 0x20
  const_0: 0x00
  id: 0x27
  length: 0x0E
  a,b,x,y: 1,0,1,0
  sync,menu,view: 0,0,0
  bumper left,right: 0,0
  stick left,right: 0,0
  dpad up,down,left,right: 0,0,0,0
  trigger left,right: 0,0
  lstick x,y: -721,-264
  rstick x,y: -467,-3185
bye

License

The software contained herein is released into the public domain under the Unlicense. In layman's terms, there are no restrictions and you are free to do whatever you want with it.

wingkeet/usb-dev