HD64F3048F16 Datasheet, PDF (301/903 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

9.5.2 Register Descriptions
Table 9.6 summarizes the registers of port 4.
Table 9.6 Port 4 Registers
Address^* Name
H'FFC5
Port 4 data direction register
H'FFC7
Port 4 data register
H'FFDA
Port 4 input pull-up MOS control
register
Note: * Lower 16 bits of the address.
Section 9 I/O Ports
Abbreviation R/W
P4DDR
W
P4DR
R/W
P4PCR
R/W
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
Modes 1 to 6 (Expanded Modes): When all areas are designated as 8-bit-access areas using the
bus width control register (ABWCR) of the bus controller, selecting 8-bit bus mode, port 4
functions as a generic input/output port. 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 value in P4DDR.
Mode 7 (Single-Chip Mode): Port 4 functions as an input/output port. 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.
P4DDR is a write-only register. Its value cannot be read. All bits return 1 when read.
P4DDR is initialized to H'00 by a reset and in hardware standby mode. In software standby mode
it retains its previous setting.
Rev. 3.00 Sep 27, 2006 page 273 of 872
REJ09B0325-0300