Register Descriptions - Renesas F-ZTAT H8 Series Hardware Manual

Section 9 I/O Ports
9.2.2

Register Descriptions

Table 9.2 summarizes the registers of port 1.
Table 9.2 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.
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
P1 DDR
Initial value
Modes
1 to 4
Read/Write
Initial value
Modes
5 to 7
Read/Write
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.
In modes 5 to 7, P1DDR is a write-only register. Its value cannot be read. All bits return 1 when
read.
Rev. 7.00 Sep 21, 2005 page 262 of 878
REJ09B0259-0700
Abbreviation
P1DDR
P1DR
7 6 5
P1 DDR P1 DDR
7 6 5
1 1 1
— — —
0 0 0
W W W
R/W
W
R/W
4 3
P1 DDR P1 DDR
4 3
1 1
— —
0 0
W W
Port 1 data direction 7 to 0
These bits select input or
output for port 1 pins
Initial Value
Modes 1 to 4 Modes 5 to 7
H'FF H'00
H'00 H'00
2 1
P1 DDR P1 DDR
2 1
1 1
— —
0 0
W W
0
P1 DDR
0
1
—
0
W