
CHAPTER 2 PIN FUNCTIONS
1 2
2.2 Pin Functions
2.2.1 P00 and P01 (Port 0)
P00 and P01 are used as a 2-bit I/O port. These pins also have external interrupt request input functions in addition
to the I/O port function.
Port 0 can be set in the following operation modes in 1-bit units.
(1) Port mode
P00 and P01 function as a 2-bit I/O port in this mode.
This 2-bit port can be set in the input or output mode in 1-bit units by the port mode register 0 (PM0). When
used as an input port, the internal pull-up resistor can be connected by using the pull-up resistor option register
0 (PU0).
(2) Control mode
P00 and P01 functions as external interrupt request input pins (INTP0 and INTP1).
INTP0 and INTP1 input external interrupt requests whose valid edge can be specified (to be the rising edge,
falling edge, or both the rising and falling edges).
2.2.2 P10 through P17 (Port 1)
P10 through P17 constitute an 8-bit input port, port 1. This port is also used to input analog signals to the internal
A/D converter.
The following operation modes can be specified in 1-bit units.
(1) Port mode
Port 1 functions as an 8-bit input port in this mode.
(2) Control mode
P10 through P17 function as analog input pins (ANI0 through ANI7) of the A/D converter.
2.2.3 P20 through P25 (Port 2)
P20 through P25 constitute a 6-bit I/O port, port 2. These pins also have functions to input/output data of the serial
interface, clock, and timer signals.
The following operation modes can be specified in 1-bit units.
(1) Port mode
In this mode, P20 through P25 function as a 6-bit I/O port. This port can be set in the input or output mode
in 1-bit units by using the port mode register 2 (PM2). When the port is used as an input port, the internal pull-
up resistor can be used if so specified by the pull-up resistor option register 2 (PU2).
(2) Control mode
In this mode, P20 through P25 are used to input/output serial interface data, clock, and timer signal, and input
timers’ capture trigger signals.
(a) SI, SO
These are I/O pins of the serial data of the serial interface.
(b) SCK
This is an I/O pin of the serial clock of the serial interface.