*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.
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== Soviet 8255 chip ==
The KP580BB55A is a soviet clone of the Intel i8255. It is used in the [[KC Compact]] and the [[Aleste 520EX]] clones of the Amstrad CPC computer.
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