Datasheet

Section 8 I/O Ports
Rev. 2.00 Aug. 20, 2008 Page 285 of 1198
REJ09B0403-0200
8.2.3 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)
• Noise canceler enable register (P3NCE)
• Noise canceler mode control register (P3NCMC)
• Noise cancel cycle setting register (NCCS)
(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
0 P30DDR 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.