USB connection – it works!

Done:

• write a clean joystick interface: 4 axes with 16-bit precision, 12 buttons (no PS3 button yet), and a hat (d-pad). This uses the excellent LUFA framework from Dean Camera.
• configure an interrupt for the serial reception (great tutorial from Dean Camera)
• write a RS232-capable emu process (docs).
• write a new Sixemugui

Sixemugui layout:

Results:

• 2ms update period = 500Hz update frequency (same as my G500 mouse) – not sure the PS3 can drive a usb device at that speed – not sure running as fast is relevant considering the Linux latency
• measured worst latency between a usb packet received by the PC from a peripheral (like a mouse) and the usb packet received by the device the joystick is connected to (for easiness, the PC – should be the PS3) is about 4.7ms, average latency is about 3.6ms

Notes:

• It’s probably better to avoid connecting both the mouse and the USB to serial device to the same usb bus.
• A kernel with realtime capabilities could probably lower the worst latency.
• It’s not good to work at a frequency higher than the mouse frequency (no mouse report in the last period => stick is set to the center => jerky movements).
• The dead zone doesn’t seem to be is proportional to the max absolute axis value.
• The report period is probably not constant without a realtime kernel (2ms is probably too low considering the Linux latency).
• For performance reasons, emu & emuclient could be merged in a single process.

Next tasks:

• build a package