Adapter for connecting USB joystick/gamepad to DB9 joystick connector found in Atari, Commodore and Amiga computers.
Joystick/gamepad usage
Plug USB joystick or gamepad into adapter's USB socket, plug the adapter into an Atari/Commodore/Amiga computer's joystick port and turn on the computer. The yellow LED (D1) should turn on indicating successful joystick/gamepad recognition. At this point you can use the (USB) joystick/gamepad as you would a plain DB9 one.
If the joystick/gamepad is recognized but does not work out-of-the-box as expected you can write a custom joystick descriptor (see below).
Custom joystick descriptors
Overview
Custom joystick descriptor is a set of 'instructions' telling the adapter how to handle USB HID reports of a specific joystick/gamepad.
Data required to write a descriptor is transmitted through adapter's UART connector (3.3 V TTL logic, 38400 baud). You can also use a software tool and a computer with USB port to display USB HID reports generated by a joystick/gamepad.