README

This sample displays the controls of an attached USB gamepad. On start-up an
information about the available controls (buttons, axes and hats) is shown and
later, when you push a button or move an axis or hat, the current state of all
controls is displayed.

Because this sample is enabled for USB plug-and-play, the USB gamepad can be
attached or removed at any time while or before the system is running. It will
be detected automatically and can be used, if it is attached. On the Raspberry
Pi 1-3 and Zero the system option USE_USB_SOF_INTR should be defined in the file
include/circle/sysconfig.h to use this sample program.

Circle supports gamepads with standard USB HID class report interface (3-0-0)
and some widespread branded gamepads with proprietary USB interfaces. This
simple sample works with all of these supported gamepads, while
sample/37-showgamepad shows the gamepad controls more easy to survey, but does
work with some known gamepads only.

There are also USB gamepads out, which support the standard USB HID class report
interface but do not have a fully qualified report descriptor. It is likely that
their support is limited to some gamepad controls.
