HD643303x Hitachi, HD643303x Datasheet - Page 162

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

7.8.2 Register Descriptions
Table 7-11 summarizes the registers of port 8.
Table 7-11 Port 8 Registers
Address*
H'FFCD
H'FFCF
Note: * Lower 16 bits of the address.
Port 8 Data Direction Register (P8DDR): P8DDR is an 8-bit write-only register that can select
input or output for each pin in port 8.
•
•
Bits 7 to 4 are reserved bits. P8DDR is a write-only register. Its value cannot be read. All bits return
1 when read.
P8DDR is initialized to H'E0 by a reset and in hardware standby mode. In software standby mode it
retains its previous setting. If a P8DDR bit is set to 1, the corresponding pin maintains its output
state in software standby mode.
Mode 1
Pins P8
as an output pin when P8
Modes 2 and 3
Port 8 is a generic input/output port. A pin port 8 becomes an output pin if the corresponding
P8DDR bit is set to 1, and an input pin if this bit is cleared to 0.
Initial value
Read/Write
Bit
3
to P8
Name
Port 8 data direction
register
Port 8 data register
1
function as input pins. Do not set P8
—
—
7
1
0
Reserved bits
DDR is set to 1, and as input pin when P8
—
—
6
1
—
—
5
1
Abbreviation
P8DDR
P8DR
147
—
W
4
0
3
P8 DDR
DDR to P8
3
W
3
0
Port 8 data direction 3 to 0
These bits select input or
output for port 8 pins
R/W
W
R/W
P8 DDR
1
DDR to 1. Pin P8
2
W
2
0
0
DDR is cleared to 0.
P8 DDR
Initial Value
H'E0
H'E0
1
W
1
0
0
P8 DDR
functions
0
W
0
0