CHAPTER 14 PORT FUNCTIONS
User’s Manual U14359EJ4V0UM
475
14.3.4 Port 3
Port 3 is an 8-bit I/O port that can be set to the input or output mode in 1-bit units.
7
6
5
4
3
2
1
0
Address
After reset
P3
P37
P36
P35
P34
P33
P32
P31
P30
FFFFF406H
Undefined
Bit position
Bit name
Function
7 to 0
P3n
(n = 7 to 0)
Port 3
I/O port
In addition to their function as port pins, the port 3 pins can also operate as the serial interface (CSI2, UART2) I/O,
external interrupt request inputs, and A/D converter external trigger input in the control mode.
(1) Operation in control mode
Port
Alternate Function
Remark
Block Type
P30
SO2/INTP130
L
P31
SI2/INTP131
H
P32
SCK2/INTP132
Serial interface (CSI2) I/O/
External interrupt request inputs
I
P33
TXD2/INTP133
L
P34
RXD2/INTP120
Serial interface (UART2) I/O/
External interrupt request inputs
H
P35
INTP121
P36
INTP122
External interrupt request inputs
Port 3
P37
ADTRG/INTP123
A/D converter external trigger input/
External interrupt request input
B
(2) I/O mode/control mode setting
The port 3 I/O mode setting is performed by the port 3 mode register (PM3), and the control mode setting is
performed by the port 3 mode control register (PMC3) and the port 3 function control register 3 (PFC3).
(a) Port 3 mode register (PM3)
This register can be read/written in 8-bit or 1-bit units.
7
6
5
4
3
2
1
0
Address
After reset
PM3
PM37
PM36
PM35
PM34
PM33
PM32
PM31
PM30
FFFFF426H
FFH
Bit position
Bit name
Function
7 to 0
PM3n
(n = 7 to 0)
Port Mode
Specifies input/output mode for P3n pin.
0: Output mode (output buffer on)
1: Input mode (output buffer off)