When competition pro attached only.
* 6808 = left/right* 6809 = up/down* 680a = Z button* 680b = y button
pressing X button sets bit 4 of all keys on keyboard matrix, pressing A button sets bit 5 of all keys on keyboard matrix
pressing delete causes all lines to go to 0x080, except line 15. All keys except delete work as expected.
* keyboard normally all keys pressed gives 0-9 0x0ff* 10 is joystick* anything above 10 is zero.
=== joypad and analogue joypad ===