Up to nine 8-bit I/O ports are implemented: P1 through P6, P8, and P9 are complete, P7 contains six individual I/O ports, and PJ contains four individual I/O ports.
- All individual I/O bits are independently programmable.
- Any combination of input, output, and interrupt conditions is possible.
- Programmable pullup or pulldown on all ports.
- Programmable drive strength on all ports.
- All eight bits of ports P1, P2, P3, and P4 support edge-selectable interrupt input.
- All instructions support read and write access to port-control registers.
- Ports can be accessed byte-wise (P1 through P9) or word-wise in pairs (PA through PD).