p2125vps20 Renesas Electronics Corporation., p2125vps20 Datasheet - Page 200

• Manufacturer Part Number: p2125vps20
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 8 I/O Ports
8.3
Port 3 is an 8-bit I/O port. Port 3 pins also function as a bidirectional data bus. 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
P3DDR specifies input or output for the pins of port 3 on a bit-by-bit basis.
Rev. 1.00 Sep. 21, 2006 Page 162 of 658
REJ09B0310-0100
Bit
7
6
5
4
3
2
1
0
Bit Name
P37DDR
P36DDR
P35DDR
P34DDR
P33DDR
P32DDR
P31DDR
P30DDR
Port 3
Port 3 Data Direction Register (P3DDR)
Initial
Value
0
0
0
0
0
0
0
0
R/W
W
W
W
W
W
W
W
W
Description
Modes 1, 2, and 3 (EXPE = 1)
The input/output direction specified by P3DDR is
ignored, and pins automatically function as data I/O pins.
Modes 2 and 3 (EXPE = 0)
The corresponding port 3 pins are output ports when
P3DDR bits are set to 1, and input ports when cleared to
0.