Pin Change Enable
Mask
Each
PCINT[23:16]-bit selects whether pin change interrupt is enabled on the
corresponding I/O pin. If PCINT[23:16] is set and the PCIE2 bit in PCICR is set, pin
change interrupt is enabled on the corresponding I/O pin. If PCINT[23:16] is
cleared, pin change interrupt on the corresponding I/O pin is
disabled.