HD6473258CP10 Datasheet, PDF (104/301 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

See section 9, Serial Communication Interface for details of the serial control bits. Pins used by the
serial communication interface are switched between input and output without regard to the values
in the data direction register.
Pins of port 5 can drive a single TTL load and a 30-pF capacitive load when they are used as output
pins. They can also drive a Darlington pair.
Table 5-11 details the port 5 registers.
Table 5-11. Port 5 Registers
Name
Port 5 data direction register
Port 5 data register
Abbreviation
P5DDR
P5DR
Read/Write
W
R/W
Initial value
H’C0
H’C0
Address
H’FFB8
H’FFBA
Port 5 Data Direction Register (P5DDR)—H’FFB8
Bit
7
6
5
4
3
2
1
0
—
— P55DDR P54DDR P53DDR P52DDR P51DDR P50DDR
Initial value
1
1
0
0
0
0
0
0
Read/Write
—
—
W
W
W
W
W
W
P5DDR is an 8-bit register that selects the direction of each pin in port 5. A pin functions as an
output pin if the corresponding bit in P5DDR is set to 1, and as an input pin if the bit is cleared to 0.
Port 5 Data Register (P5DR)—H’FFBA
Bit
7
6
5
4
3
2
1
0
—
—
P55
P54
P53
P52
P51
P50
Initial value
1
1
0
0
0
0
0
0
Read/Write
—
—
R/W R/W R/W R/W R/W R/W
P5DR is an 8-bit register containing output data for pins P55 to P50, and controlling their input pull-
ups. When the CPU reads P5DR, for output pins (P5DDR = 1) it reads the value in the P5DR latch,
but for input pins (P5DDR = 0), it obtains the logic level directly from the pin, bypassing the P5DR
latch. This also applies to pins used for serial communication.
MOS Pull-Ups: Are available for input pins, including serial communication input pins. Software
can turn the MOS pull-up on by writing a 1 in P5DR, and turn it off by writing a 0. The pull-ups are
automatically turned off for output pins.
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