Up to six 8-bit I/O ports are implemented: for 64-pin options, P1, P2, P4, P6, and are complete, P5 is reduced to 6-bit I/O, and P3 to 5-bit I/O. For 48-pin options, P6 is reduced to 4-bit I/O, P2 to 1-bit I/O, and P3 is completely removed. Port PJ contains four individual I/O ports, common to all devices.
- All individual I/O bits are independently programmable.
- Any combination of input, output, and interrupt conditions is possible.
- Pullup or pulldown on all ports is programmable.
- Drive strength on all ports is programmable.
- Edge-selectable interrupt and LPM4.5 wake-up input capability is available for all bits of ports P1 and P2.
- Read and write access to port-control registers is supported by all instructions.
- Ports can be accessed byte-wise (P1 through P6) or word-wise in pairs (PA through PC).