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CHAPTER 2
PIN FUNCTIONS
User’s Manual U12790EJ2V0UD
2.2 Description of Pin Functions
2.2.1 P00 to P07 (Port 0)
These are 8-bit I/O port pins. Besides serving as I/O port pins, they also function as external interrupt inputs. The
following operating modes can be specified in 1-bit units.
(1) Port mode
These pins function as an 8-bit I/O port that can be set to input or output mode in 1-bit units using port
mode register 0.
(2) Control mode
These pins function as external interrupt input pins (INTP0 to INTP7).
INTP0 to INTP7 are external interrupt input pins for which the valid edge (rising edge, falling edge, or both
rising and falling edges) can be specified.
2.2.2 P10 to P17 (Port 1)
These are 8-bit input port pins. Besides serving as input port pins, they also function as A/D converter analog
inputs.
The following operating modes can be specified in 1-bit units.
(1) Port mode
These pins function as an 8-bit input port.
(2) Control mode
These pins function as A/D converter analog input pins (ANI0 to ANI7).
2.2.3 P20 to P27 (Port 2)
These are 8-bit I/O port pins. Besides serving as I/O port pins, they also have serial interface data input/output,
clock I/O, automatic transmit/receive busy input, and strobe output functions.
The following operating modes can be specified in 1-bit units.
(1) Port mode
These pins function as an 8-bit I/O port that can be set to input or output mode in 1-bit units using port mode
register 2.
(2) Control mode
These pins function as serial interface data I/O, clock I/O, automatic transmit/receive busy input, and strobe
output pins.
(a) SI0, SI1, SO0, SO1, SDA0Note, SDA1Note
These are serial interface serial data I/O pins. SDA0 and SDA1 are N-ch open drain.
(b) SCK0 and SCK1, SCLNote
These are serial interface serial clock I/O pins.
SCL is N-ch open drain.
Note
For I2C bus mode