Register Descriptions - Renesas F-ZTAT H8 Series Hardware Manual

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.
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 7
P4 DDR
7
Initial value 0
Read/Write W
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.
6 5
P4 DDR P4 DDR P4 DDR
6 5
0 0
W W
Port 4 data direction 7 to 0
These bits select input or output for port 4 pins
Abbreviation
P4DDR
P4DR
P4PCR
4 3 2
P4 DDR P4 DDR
4 3 2
0 0 0
W W W
Rev. 7.00 Sep 21, 2005 page 271 of 878
Section 9 I/O Ports
R/W Initial Value
W H'00
R/W H'00
R/W H'00
1 0
P4 DDR P4 DDR
1 0
0 0
W W
REJ09B0259-0700