Datasheet

Rev. 3.00, 03/04, page 191 of 830
8.3 Port 3
Port 3 is an 8-bit I/O port. Port 3 pins also function as a bidirectional data bus, wake-up event
input pins. Port 3 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 pins of port 3.
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
In normal extended mode:
Bidirectional data bus
In other mode:
The corresponding port 3 pins are output ports when
the P3DDR bits are set to 1, and input ports when
cleared to 0.
8.3.2 Port 3 Data Register (P3DR)
P3DR stores output data for the port 3 pins.
Bit Bit Name Initial Value R/W Description
7 P37DR 0 R/W
6 P36DR 0 R/W
5 P35DR 0 R/W
4 P34DR 0 R/W
3 P33DR 0 R/W
2 P32DR 0 R/W
1 P31DR 0 R/W
0 P30DR 0 R/W
In normal extended mode (ADMXE = 0):
If a port 3 read is performed while the P3DDR bits are
set to 1, the P3DR values are read. When the P3DDR
bits are cleared to 0, 1 is read.
In other mode:
If a port 3 read is performed while the P3DDR bits are
set to 1, the P3DR values are read. If a port 3 read is
performed while the P3DDR bits are cleared to 0, the
pin states are read.