Texas Instruments MSP430x4xx - Manual (Page 189)

Digital I/O Operation
9-6 Digital I/O
Interrupt Edge Select Registers P1IES, P2IES
Each PxIES bit selects the interrupt edge for the corresponding I/O pin.
Bit = 0: The PxIFGx flag is set with a low-to-high transition
Bit = 1: The PxIFGx flag is set with a high-to-low transition
Note: Writing to PxIESx
Writing to P1IES, or P2IES can result in setting the corresponding interrupt
flags.
PxIESx PxINx PxIFGx
0
→
1 0 May be set
0
→
1 1 Unchanged
1
→
0 0 Unchanged
1
→
0 1 May be set
Interrupt Enable P1IE, P2IE
Each PxIE bit enables the associated PxIFG interrupt flag.
Bit = 0: The interrupt is disabled
Bit = 1: The interrupt is enabled
9.2.6 Configuring Unused Port Pins
Unused I/O pins should be configured as I/O function, output direction, and left
unconnected on the PC board, to reduce power consumption. The value of the
PxOUT bit is don’t care, since the pin is unconnected. See chapter System
Resets, Interrupts, and Operating Modes for termination unused pins.