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9.2.2.7 PIA module

The PIA 6520 is a chip with two I/O ports (Parallel Interface Adapter) and four additional handshake lines. The chip is pretty the same for Port A and B, only that Port A implements handshake on read operation and port B on write operation.

Version numbers: Major 1, Minor 0.

TypeNameDescription
UBYTEORAOutput register A
UBYTEDDRAData Direction Register A
UBYTECTRLAControl Register A
UBYTEORBOutput register B
UBYTEDDRBData Direction Register B
UBYTECTRLBControl Register B
UBYTECABSTATEBit 7 = state of CA2, Bit 6 = state of CB2