Datasheet

Section 8 I/O Ports
Rev. 3.00 Mar 21, 2006 page 175 of 788
REJ09B0300-0300
8.3 Port 2
Port 2 is an 8-bit I/O port. Port 2 pins also function as address bus output function, 8-bit PWM
output pins, and the timer connection output pin. Port 2 functions change according to the
operating mode. Port 2 has an on-chip input pull-up MOS function that can be controlled by
software. Port 2 has the following registers.
• Port 2 data direction register (P2DDR)
• Port 2 data register (P2DR)
• Port 2 pull-up MOS control register (P2PCR)
8.3.1 Port 2 Data Direction Register (P2DDR)
P2DDR specifies input or output for the pins of port 2 on a bit-by-bit basis.
Bit Bit Name Initial Value R/W Description
7 P27DDR 0 W
6 P26DDR 0 W
5 P25DDR 0 W
4 P24DDR 0 W
3 P23DDR 0 W
2 P22DDR 0 W
1 P21DDR 0 W
0 P20DDR 0 W
In Mode 1:
The corresponding port 2 pins are address
outputs, regardless of the P2DDR setting.
Modes 2 and 3 (EXPE = 1):
The corresponding port 2 pins are address
outputs or PWM outputs when P2DDR bits are
set to 1, and input ports when cleared to 0. P27 to
P24 are switched from address outputs to output
ports by setting the IOSE bit to 1.
P27 can be used as an on-chip peripheral module
output pin regardless of the P27DDR setting, but
to ensure normal access to external space, P27
should not be set as an on-chip peripheral
module output pin when port 2 pins are used as
address output pins.
Modes 2 and 3 (EXPE = 0):
The corresponding port 2 pins are output ports or
PWM outputs when P2DDR bits are set to 1, and
input ports when cleared to 0.
P27 can be used as an on-chip peripheral module
output pin regardless of the P27DDR setting.