HD6433045 HITACHI [Hitachi Semiconductor], HD6433045 Datasheet - Page 260

• Manufacturer Part Number: HD6433045
• Description: Hitachi Single-Chip Microcomputer
• Manufacturer: HITACHI [Hitachi Semiconductor]

9.2.2 Register Descriptions
Table 9-2 summarizes the registers of port 1.
Table 9-2 Port 1 Registers
Address*
H'FFC0
H'FFC2
Note: * Lower 16 bits of the address.
Port 1 Data Direction Register (P1DDR): P1DDR is an 8-bit write-only register that can select
input or output for each pin in port 1.
Modes 1 to 4 (Expanded Modes with On-Chip ROM Disabled): P1DDR values are fixed at 1
and cannot be modified. Port 1 functions as an address bus.
Modes 5 and 6 (Expanded Modes with On-Chip ROM Enabled): A pin in port 1 becomes an
address output pin if the corresponding P1DDR bit is set to 1, and a generic input pin if this bit is
cleared to 0.
Mode 7 (Single-Chip Mode): Port 1 functions as an input/output port. A pin in port 1 becomes an
output pin if the corresponding P1DDR bit is set to 1, and an input pin if this bit is cleared to 0.
Bit
Modes
1 to 4
Modes
5 to 7
Initial value
Read/Write
Initial value
Read/Write
Name
Port 1 data direction register
Port 1 data register
P1 DDR
7
—
W
7
1
0
P1 DDR
6
—
W
6
1
0
P1 DDR
5
—
W
5
1
0
Abbreviation
P1DDR
P1DR
Port 1 data direction 7 to 0
These bits select input or
output for port 1 pins
247
P1 DDR
4
—
W
4
1
0
P1 DDR
R/W
W
R/W
3
—
W
3
1
0
P1 DDR
Modes 1 to 4
H'FF
H'00
2
—
W
2
1
0
P1 DDR
Initial Value
1
—
W
1
1
0
Modes 5 to 7
H'00
H'00
P1 DDR
0
—
W
0
1
0