
280
9.3
Port 3
9.3.1
Overview
Port 3 is a 7-bit I/O port. Port 3 pins also function as SCI I/O pins (TxD0, RxD0, SCK0, TxD1,
RxD1, and SCK1), external interrupt input pins (
IRQ4 and IRQ5), and an external expansion
interrupt input pin (
EXIRQ7). Port 3 pin functions are the same in all operating modes.
The interrupt input pins (
IRQ4 and IRQ5) and the external expansion interrupt input pin
(
EXIRQ7) are Schmitt-triggered inputs.
Figure 9-2 shows the port 3 pin configuration.
P36
P35
P34
P33
P32
P31
P30
(input/output)
/
EXIRQ7 (input)
/SCK1(input/output)/
IRQ5 (input)
/RxD1 (input)
/TxD1 (output)
/SCK0(input/output)/
IRQ4 (input)
/RxD0 (input)
/TxD0 (output)
Port 3 pins
Port 3
Figure 9-2 Port 3 Pin Functions
9.3.2
Register Configuration
Table 9-4 shows the port 3 register configuration.
Table 9-4
Port 3 Registers
Name
Abbreviation
R/W
Initial Value*
2
Address*
1
Port 3 data direction register
P3DDR
W
H'00
H'FE32
Port 3 data register
P3DR
R/W
H'00
H'FF02
Port 3 register
PORT3
R
H'00
H'FFB2
Port 3 open-drain control register
P3ODR
R/W
H'00
H'FE46
Interrupt request input pin select register 0 IPINTSEL0
R/W
H'00
H'FE4A
Notes: *1 Lower 16 bits of the address.
*2 Value of bits 6 to 0.