HD6433308 Datasheet, PDF (94/349 Pages) Hitachi Semiconductor – Hitachi Single-Chip MicroComputer

Table 5-3 details the port 1 registers.
Table 5-3. Port 1 Registers
Name
Abbreviation
Port 1 data direction register P1DDR
Port 1 data register
P1DR
Read/Write
W
R/W
Initial value
Address
H’FF (mode 1)
H’FFB0
H’00 (modes 2 and 3)
H’00
H’FFB2
Port 1 Data Direction Register (P1DDR)—H’FFB0
Bit
7
6
5
4
3
2
1
0
P17DDR P16DDR P15DDR P14DDR P13DDR P12DDR P11DDR P10DDR
Mode 1
Initial value
1
1
1
1
1
1
1
1
Read/Write
—
—
—
—
—
—
—
—
Modes 2 and 3
Initial value
0
0
0
0
0
0
0
0
Read/Write
W
W
W
W
W
W
W
W
P1DDR is an 8-bit register that selects the direction of each pin in port 1. A pin functions as an
output pin if the corresponding bit in P1DDR is set to “1,” and as an input pin if the bit is cleared to
“0.”
Port 1 Data Register (P1DR)—H’FFB2
Bit
Initial value
Read/Write
7
6
5
4
3
2
1
0
P17
P16
P15
P14
P13
P12
P11
P10
0
0
0
0
0
0
0
0
R/W R/W R/W R/W R/W R/W R/W R/W
P1DR is an 8-bit register containing the data for pins P17 to P10. When the CPU reads P1DR, for
output pins it reads the value in the P1DR latch, but for input pins, it obtains the logic level directly
from the pin, bypassing the P1DR latch.
MOS Pull-Ups: Are available for input pins in modes 2 and 3. Software can turn on the MOS
pull-up by writing a “1” in P1DR, and turn it off by writing a “0.” The pull-ups are automatically
turned off for output pins in modes 2 and 3, and for all pins in mode 1.
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