HD643303x Hitachi, HD643303x Datasheet - Page 166

• Manufacturer Part Number: HD643303x
• Description: Hitachi Microcomputer
• Manufacturer: Hitachi

Port 9 Data Direction Register (P9DDR): P9DDR is an 8-bit write-only register that can select
input or output for each pin in port 9.
A pin in port 9 becomes an output pin if the corresponding P9DDR bit is set to 1, and an input pin
if this bit is cleared to 0.
P9DDR is a write-only register. Its value cannot be read. All bits return 1 when read.
P9DDR is initialized to H'C0 by a reset and in hardware standby mode. In software standby mode it
retains its previous setting. If a P9DDR bit is set to 1, the corresponding pin maintains its output
state in software standby mode.
Port 9 Data Register (P9DR): P9DR is an 8-bit readable/writable register that stores data for pins
P9
When a bit in P9DDR is set to 1, if port 9 is read the value of the corresponding P9DR bit is
returned directly. When a bit in P9DDR is cleared to 0, if port 9 is read the corresponding pin level
is read.
Bit
Initial value
Read/Write
Bit
Initial value
Read/Write
4
, P9
2
, and P9
0
.
—
—
—
—
Reserved bits
Reserved bits
7
1
7
1
—
—
—
—
6
1
6
1
R/W
—
—
W
5
0
5
0
P9 DDR
151
R/W
P9
4
W
4
0
4
0
4
Port 9 data direction 4, 2, 0
These bits select input or
output for port 9 pins
R/W
—
—
W
3
0
3
0
Port 9 data 4, 2, 0
These bits store data
for port 9 pins
P9 DDR
R/W
P9
2
W
2
0
2
0
2
R/W
—
—
W
1
0
1
0
P9 DDR
R/W
P9
0
W
0
0
0
0
0