HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 267

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

Port 3 Data Direction Register (P3DDR): P3DDR is an 8-bit write-only register that can select
input or output for each pin in port 3.
Modes 1 to 6 (Expanded Modes): Port 3 functions as a data bus. P3DDR is ignored.
Mode 7 (Single-Chip Mode): Port 3 functions as an input/output port. A pin in port 3 becomes an
output port if the corresponding P3DDR bit is set to 1, and an input port if this bit is cleared to 0.
P3DDR is a write-only register. Its value cannot be read. All bits return 1 when read.
P3DDR is initialized to H'00 by a reset and in hardware standby mode. In software standby mode
it retains its previous setting. If a P3DDR bit is set to 1, the corresponding pin maintains its output
state in software standby mode.
Port 3 Data Register (P3DR): P3DR is an 8-bit readable/writable register that stores output data
for pins P3
corresponding P3DR bit is returned. When a bit in P3DDR is cleared to 0, if port 3 is read the
corresponding pin level is read.
P3DR is initialized to H'00 by a reset and in hardware standby mode. In software standby mode it
retains its previous setting.
Bit
Initial value
Read/Write
Bit
Initial value
Read/Write
7
to P3
P3 DDR
0
. When a bit in P3DDR is set to 1, if port 3 is read the value of the
R/W
P3
7
W
7
0
7
0
7
P3 DDR
R/W
P3
6
W
6
0
6
0
6
P3 DDR
R/W
P3
5
W
5
0
5
0
Port 3 data direction 7 to 0
These bits select input or output for port 3 pins
Port 3 data 7 to 0
These bits store data for port 3 pins
5
P3 DDR
254
R/W
P3
4
W
4
0
4
0
4
P3 DDR
R/W
P3
3
W
3
0
3
0
3
P3 DDR
R/W
P3
2
W
2
0
2
0
2
P3 DDR
R/W
P3
1
W
1
0
1
0
1
P3 DDR
R/W
P3
0
W
0
0
0
0
0