HD64F3028F25 Datasheet, PDF (290/925 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

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.
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
Port 3 data direction 7 to 0
These bits select input or output for port 3 pins
Modes 1 to 5 (Expanded Modes): Port 3 functions as a data bus, regardless of the P3DDR
settings.
Modes 6 and 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. Therefore, if a transition is made to software standby mode while
port 3 is functioning as an input/output port and a P3DDR bit is set to 1, the corresponding pin
maintains its output state.
Port 3 Data Register (P3DR): P3DR is an 8-bit readable/writable register that stores output data
for port 3. When port 3 functions as an output port, the value of this register is output. When a bit
in P3DDR is set to 1, if port 3 is read the value of the corresponding P3DR bit is returned. When a
bit in P3DDR is cleared to 0, if port 3 is read the corresponding pin logic level is read.
Bit
Initial value
Read/Write
7
P3₇
0
R/W
6
P3₆
0
R/W
5
P3₅
0
R/W
4
P3₄
0
R/W
3
P3₃
0
R/W
2
P3₂
0
R/W
1
P3₁
0
R/W
0
P3₀
0
R/W
Port 3 data 7 to 0
These bits store data for port 3 pins
P3DR is initialized to H'00 by a reset and in hardware standby mode. In software standby mode it
retains its previous setting.
Rev. 2.00, 09/03, page 258 of 890