6.10.3 General-Purpose Input/Output Port (I/O)
Up to 19 I/O ports are implemented.
- P1 and P2 are full 8-bit ports; P3 has 3 bits implemented.
- All individual I/O bits are independently programmable.
- Any combination of input, output, and interrupt conditions is possible.
- All ports support programmable pullup or pulldown.
- Edge-selectable interrupt and LPM3.5 and LPM4.5 wake-up input capability is available for P1 and P2.
- Read and write access to port-control registers is supported by all instructions.
- Ports can be accessed byte-wise or word-wise in pairs.
- CapTIvate functionality is supported on all CAPx.y pins.
Configuration of digital I/Os after BOR reset
To prevent any cross currents during start-up of the device, all port pins are high-impedance with Schmitt triggers and module functions disabled. To enable the I/O functions after a BOR reset, the ports must be configured first and then the LOCKLPM5 bit must be cleared. For details, see the Configuration After Reset section in the Digital I/O chapter of the MP430FR4xx and MP430FR2xx Family User's Guide.