=== 0Eh - External Dataregister Port A ===
This register receives data from the CPC keyboard (or joystick), for more information read the chapter about the [[Programming:Keyboard_scanning|CPC Keyboard Matrix]]. This register can be also used as output port by setting bit 6 of the PSG control register to 1 (that would allow to use the six data pins of the joystick connector to output data to external hardware).
=== 0Fh - External Dataregister Port B ===