HD6413007F20 Datasheet, PDF (279/798 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

8.2.2 Register Configuration
Table 8.2 summarizes the registers of port 4.
Table 8.2 Port 4 Registers
Address* Name
Abbreviation R/W
H'EE003 Port 4 data direction register
P4DDR
W
H'FFFD3 Port 4 data register
P4DR
R/W
H'EE03E Port 4 input pull-up MOS control register P4PCR
R/W
Note: * Lower 20 bits of the address in advanced mode.
8. I/O Ports
Initial Value
H'00
H'00
H'00
Port 4 Data Direction Register (P4DDR): P4DDR is an 8-bit write-only register that can select
input or output for each pin in port 4.
Bit
Initial value
Read/Write
7
6
5
4
3
2
1
0
P4₇DDR P4₆DDR P4₅DDR P4₄DDR P4₃DDR P4₂DDR P4₁DDR P4₀DDR
0
0
0
0
0
0
0
0
W
W
W
W
W
W
W
W
Port 4 data direction 7 to 0
These bits select input or output for port 4 pins
When all areas are designated as 8-bit-access areas by the bus controller's bus width control
register (ABWCR), selecting 8-bit bus mode, port 4 functions as an input/output port. In this case,
a pin in port 4 becomes an output port if the corresponding P4DDR bit is set to 1, and an input
port if this bit is cleared to 0.
When at least one area is designated as a 16-bit-access area, selecting 16-bit bus mode, port 4
functions as part of the data bus, regardless of the P4DDR settings.
P4DDR is initialized to H'00 by a reset and in hardware standby mode. In software standby mode
it retains its previous setting.
ABWCR and P4DDR are not initialized in software standby mode. When port 4 functions as a
generic input/output port, if a P4DDR bit is set to 1, the corresponding pin maintains its output
state in software standby mode.
Rev.5.00 Sep. 12, 2007 Page 249 of 764
REJ09B0396-0500