-Dual
purpose I/O port.
-In min. component design, it is used as a general
purpose I/O port.
•-
In larger designs with external memory, it becomes a multiplexed data
bus:
–Low byte of address bus, strobed by ALE.
–8-bit instruction bus, strobed by
PSEN.
–8-bit data bus, strobed by WR
and RD.