Up to ten 8-bit I/O ports are implemented: For 100- and 113-pin options, P1 through P10 are complete, and P11 contains three individual I/O ports. For 80-pin options, P1 through P7 are complete, P8 contains seven individual I/O ports, and P9 through P11 do not exist. 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 P11) or word-wise in pairs (PA through PF).