Z80 Assembly 61: Interfacing with the Z80 PIO (Parallel I/O)
The Role of the Z80 PIO The Z80 PIO (Parallel Input/Output) chip is a dedicated peripheral designed to relieve the Z80 CPU of the burden of managing complex, high-speed, general-purpose I/O. It provides two independent 8-bit ports (Port A and Port B), each configurable as input or output. Advantage: The PIO handles handshaking and interrupt generation entirely in hardware, saving CPU cycles. PIO Communication Ports The PIO chip occupies four consecutive I/O port addresses on the Z80 bus, typically accessed via OUT and IN instructions: ...