HD6473032F Datasheet, PDF (162/572 Pages) Hitachi Semiconductor – Hitachi Microcomputer

7.8.2 Register Descriptions
Table 7-11 summarizes the registers of port 8.
Table 7-11 Port 8 Registers
Address*
Name
Abbreviation
R/W
H'FFCD
Port 8 data direction
P8DDR
W
register
H'FFCF
Port 8 data register
P8DR
R/W
Note: * Lower 16 bits of the address.
Initial Value
H'E0
H'E0
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.
7
6
5
4
3
2
1
0
Bit
—
—
—
— P8₃DDR P8₂DDR P8₁DDR P8₀DDR
Initial value ¹
1
1
0
0
0
0
0
Read/Write ^—
—
—
W
W
W
W
W
Reserved bits
Port 8 data direction 3 to 0
These bits select input or
output for port 8 pins
• Mode 1
Pins P8₃ to P8₁ function as input pins. Do not set P8₃DDR to P8₁DDR to 1. Pin P8₀ functions
as an output pin when P8₀DDR is set to 1, and as input pin when P8₀DDR is cleared to 0.
• 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.
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.
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