HD6473032F Datasheet, PDF (138/572 Pages) Hitachi Semiconductor – Hitachi Microcomputer

7.2.2 Register Descriptions
Table 7-2 summarizes the registers of port 1.
Table 7-2 Port 1 Registers
Address* Name
H'FFC0
Port 1 data direction register
H'FFC2
Port 1 data register
Note: * Lower 16 bits of the address.
Abbreviation
P1DDR
P1DR
R/W
Initial Value
W
H'00
R/W
H'00
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.
Bit
Initial value
Read/Write
7
6
5
4
3
2
1
0
P1₇DDR P1₆DDR P1₅DDR P1₄DDR P1₃DDR P1₂DDR P1₁DDR P1₀DDR
0
0
0
0
0
0
0
0
W
W
W
W
W
W
W
W
Port 1 data direction 7 to 0
These bits select input or
output for port 1 pins
Mode 1: 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.
Modes 2 and 3 (Single-Chip Modes): 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.
P1DDR is a write-only register. Its value cannot be read. All bits return 1 when read.
P1DDR is initialized to H'00 by a reset and in hardware standby mode. In software standby mode it
retains its previous setting. If a P1DDR bit is set to 1, the corresponding pin maintains its output
state in software standby mode.
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