*The 8255 PPI is not emulated by the Pre-ASIC. These CPC’s have a real PPI chip and therefore behave like the first generation of CPC’s.
*The ASIC PPI does not support Group Modes other than Groupe Mode 0.
*On the ASIC PPI, Port B is always defined as input and Port C is always defined as output.
*On a real PPI chip, when the PPI control register is used (with bit7=1) to configure the ports, the output latches of all ports are reset to 0. The ASIC poorly emulates the PPI and does not reset these ports.