Texas Instruments MSP430x1xx - Manual (Page 122)

Introduction
8-2
8.1 Introduction
The general-purpose I/O ports of the MSP430 are designed to give maximum
flexibility. Each I/O line is individually configurable, and most have interrupt
capability.
There are two different types of I/O port modules in the MSP430x1xx family
devices. Ports P1 and P2 are of one type, and ports P3 to P6 are of another
type. Both types have the capability to control input/output direction and output
level, to read the level applied to a pin, and to control if a port or module function
is applied to a pin. The port module for P1 and P2 have interrupt capability; flag,
enable, and edge sensitivity are available individually for each bit.
MSP430x11x and MSP430x11x1 devices have ports P1 and P2 implemented;
MSP430x13x and MSP430x14x have ports P1 to P6 implemented.