P120 To P124 (Port 12) - NEC 78K0R/KE3 User Manual

(1) Port mode
P70 to P77 function as an 8-bit I/O port. P70 to P77 can be set to input or output port in 1-bit units using port
mode register 7 (PM7). Use of an on-chip pull-up resistor can be specified by pull-up resistor option register 7
(PU7).
(2) Control mode
P70 to P77 function as key interrupt input, and external interrupt request input.
(a) KR0 to KR7
These are the key interrupt input pins
(b) INTP8 to INTP11
These are the external interrupt request input pins for which the valid edge (rising edge, falling edge, or both
rising and falling edges) can be specified.

2.2.9 P120 to P124 (port 12)

P120 functions as a 1-bit I/O port. P121 to P124 function as a 4-bit input port. These pins also function as external
interrupt request input, potential input for external low-voltage detection, connecting resonator for main system clock,
connecting resonator for subsystem clock, and external clock input for main system clock.
The following operation modes can be specified in 1-bit units.
(1) Port mode
P120 functions as a 1-bit I/O port. P120 can be set to input or output port using port mode register 12 (PM12).
Use of an on-chip pull-up resistor can be specified by pull-up resistor option register 12 (PU12).
P121 to P124 function as a 4-bit input port.
(2) Control mode
P120 to P124 function as external interrupt request input, potential input for external low-voltage detection,
connecting resonator for main system clock, connecting resonator for subsystem clock, and external clock input
for main system clock.
(a) INTP0
This is an external interrupt request input pin for which the valid edge (rising edge, falling edge, or both rising
and falling edges) can be specified.
(b) EXLVI
This is a potential input pin for external low-voltage detection.
(c) X1, X2
These are the pins for connecting a resonator for main system clock.
(d) EXCLK
This is an external clock input pin for main system clock.
(e) XT1, XT2
These are the pins for connecting a resonator for subsystem clock.
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CHAPTER 2 PIN FUNCTIONS
User's Manual U17854EJ9V0UD