Pin Change Enable
Mask [11:8]
Each PCINT[11:8]-bit
selects whether pin change interrupt is enabled on the corresponding I/O pin. If
PCINT[11:8] is set and the PCICR.PCIE1 is set, pin change interrupt is enabled on
the corresponding I/O pin. If PCINT[11:8] is cleared, pin change interrupt on the
corresponding I/O pin is disabled.