Datasheet

Section 8 I/O Ports
Rev. 2.00 Sep. 28, 2009 Page 191 of 870
REJ09B0429-0200
8.3 Port 3
Port 3 is an 8-bit I/O port. Port 3 pins can also function as the bidirectional data bus and de-
bounced input pins. The pin functions change according to the operating mode. Port 3 has the
following registers.
• Port 3 data direction register (P3DDR)
• Port 3 data register (P3DR)
• Port 3 pull-up MOS control register (P3PCR)
8.3.1 Port 3 Data Direction Register (P3DDR)
The individual bits of P3DDR specify input or output for the port 3 pins.
Bit Bit Name Initial Value R/W Description
7 P37DDR 0 W
6 P36DDR 0 W
5 P35DDR 0 W
4 P34DDR 0 W
3 P33DDR 0 W
2 P32DDR 0 W
1 P31DDR 0 W
• Normal extended mode (ADMXE = 0)
The pins function as bidirectional data bus pins.
• Other modes
When set to 1, the corresponding pins function as
output port pins; when cleared to 0, function as input
port pins.
0 P30DDR 0 W