HD6473258CP10 Datasheet, PDF (94/301 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

pins. They can also drive a Darlington pair.
Table 5-7 details the port 3 registers.
Table 5-7. Port 3 Registers
Name
Port 3 data direction register
Port 3 data register
Abbreviation
P3DDR
P3DR
Read/Write
W
R/W
Initial value
H’FF
H’00
Address
H’FFB4
H’FFB6
Port 3 Data Direction Register (P3DDR)—H’FFB4
Bit
Initial value
Read/Write
7
6
5
4
3
2
1
0
P37DDR P36DDR P35DDR P34DDR P33DDR P32DDR P31DDR P30DDR
0
0
0
0
0
0
0
0
W
W
W
W
W
W
W
W
P3DDR is an 8-bit register that selects the direction of each pin in port 3. A pin functions as an
output pin if the corresponding bit in P3DDR is set to 1, and as an input pin if the bit is cleared to 0.
Port 3 Data Register (P3DR)—H’FFB6
Bit
Initial value
Read/Write
7
6
5
4
3
2
1
0
P37
P36
P35
P34
P33
P32
P31
P30
0
0
0
0
0
0
0
0
R/W R/W R/W R/W R/W R/W R/W R/W
P3DR is an 8-bit register containing output data for pins P37 to P30 in mode 3, and controlling their
input pull-ups.
MOS Pull-Ups: Are available for input pins in mode 3. Software can turn on the MOS pull-up by
writing a 1 in P3DR, and turn it off by writing a 0. The pull-ups are automatically turned off for
output pins in mode 3, and for all pins in modes 1 and 2.
Modes 1 and 2: In the expanded modes, port 3 is automatically used as the data bus. The values in
P3DDR and P3DR are ignored.
Mode 3: In the single-chip mode, port 3 can be used as a general-purpose input/output port, or a
parallel-handshaking input or output port.
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