HD6433308 HITACHI [Hitachi Semiconductor], HD6433308 Datasheet - Page 120

• Manufacturer Part Number: HD6433308
• Description: Hitachi Single-Chip MicroComputer
• Manufacturer: HITACHI [Hitachi Semiconductor]

Port 8 Data Direction Register (P8DDR)—H’FFBD
Bit
Modes 1 and 2
Mode 3
P8DDR is an 8-bit register that selects the direction of each pin in port 8. A pin functions as an
output pin if the corresponding bit in P8DDR is set to “1,” and as in input pin if the bit is cleared to
“0.”
Bit 7 is reserved. It cannot be modified, and is always read as "1."
Port 8 Data Register (P8DR)—H’FFBF
Bit
Initial value
Read/Write
P8DR is an 8-bit register containing the data for pins P8
output pins (P8DDR = "1") it reads the value in the P8DR latch, but for input pins (P8DDR = "0"),
it obtains the logic level directly from the pin, bypassing the P8DR latch. This also applies to pins
used for dual-port RAM register select input, interrupt input, serial communication, and E clock or
IOS output.
Bit 7 is reserved. It cannot be modified, and is always read as "1."
MOS Pull-Ups: Are available for input pins in all modes, including pins used for dual-port RAM
register select input, interrupt input, or serial communication input. Software can turn the MOS
pull-up on by writing a “1” in P8DR, and turn it off by writing a “0.”
Initial value
Read/Write
Initial value
Read/Write
—
—
—
—
—
7
1
1
7
1
P8
R/W
6
P8
W
W
DDR P8
6
0
0
6
0
6
R/W
5
P8
W
W
DDR P8
5
0
0
5
0
5
105
R/W
4
P8
W
W
DDR P8
4
0
0
4
0
4
6
to P8
R/W
3
P8
W
W
DDR P8
3
0
0
3
0
3
0
. When the CPU reads P8DR, for
R/W
2
P8
W
W
DDR P8
2
0
0
2
0
2
R/W
1
P8
W
W
DDR P8
1
0
0
1
0
1
R/W
0
P8
W
W
DDR
0
1
0
0
0
0