HD64F2149 Datasheet, PDF (242/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

8.4.2 Register Configuration
Table 8.6 shows the port 3 register configuration.
Table 8.6 Port 3 Registers
Name
Abbreviation R/W
Port 3 data direction register P3DDR
W
Port 3 data register
P3DR
R/W
Port 3 MOS pull-up control
P3PCR
R/W
register
Note: * Lower 16 bits of the address.
Initial Value
H'00
H'00
H'00
Address*
H'FFB4
H'FFB6
H'FFAE
Port 3 Data Direction Register (P3DDR)
Bit
Initial value
Read/Write
7
6
5
4
3
2
1
0
P37DDR P36DDR P35DDR P34DDR P33DDR P32DDR P31DDR P30DDR
0
0
0
0
0
0
0
0
W
W
W
W
W
W
W
W
P3DDR is an 8-bit write-only register, the individual bits of which specify input or output for the
pins of port 3. P3DDR cannot be read; if it is, an undefined value will be returned.
P3DDR is initialized to H'00 by a reset and in hardware standby mode. It retains its prior state in
software standby mode.
• 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.
After a reset, and in hardware standby mode or software standby mode, the data I/O pins go to
the high-impedance state.
• 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.
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