Datasheet

Section 8 I/O Ports
Rev. 2.00 Sep. 28, 2009 Page 221 of 870
REJ09B0429-0200
8.9 Port 9
Port 9 is an 8-bit I/O port. Port 9 pins can also function as the bus control input/output and system
clock output pins. The pin functions change according to the operating mode. Port 9 has the
following registers.
• Port 9 data direction register (P9DDR)
• Port 9 data register (P9DR)
8.9.1 Port 9 Data Direction Register (P9DDR)
The individual bits of P9DDR specify input or output for the port 9 pins.
Bit Bit Name Initial Value R/W Description
7 P97DDR 0 W
6 P96DDR 0 W
5 P95DDR 0 W
4 P94DDR 0 W
3 P93DDR 0 W
2 P92DDR 0 W
1 P91DDR 0 W
0 P90DDR 0 W
[P97DDR, P95DDR to P90DDR]
If port 9 pins are specified for use as the general I/O
port, the corresponding pins function as output port
when the P97DDR, and P95DDR to P90DDR bits are
set to 1, and as input port when cleared to 0.
[P96DDR]
The corresponding port 9 pin functions as the system
clock output pin (φ) when this bit is set to 1, and as
the general I/O port when cleared to 0.