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1. Port data register 1 (PDR1)
Bit
7
P1
Initial value
0
Read/Write
R/W
PDR1 is an 8-bit register that stores data for port 1 pins P1
bits are set to 1, the values stored in PDR1 are read, regardless of the actual pin states. If port 1 is
read while PCR1 bits are cleared to 0, the pin states are read.
Upon reset, PDR1 is initialized to H'00.
2. Port control register 1 (PCR1)
Bit
7
PCR1
Initial value
0
Read/Write
W
PCR1 is an 8-bit register for controlling whether each of the port 1 pins P1
input pin or output pin. Setting a PCR1 bit to 1 makes the corresponding pin an output pin, while
clearing the bit to 0 makes the pin an input pin. The settings in PCR1 and in PDR1 are valid only
when the corresponding pin is designated in PMR1 as a general I/O pin.
Upon reset, PCR1 is initialized to H'00.
PCR1 is a write-only register, which is always read as all 1s.
3. Port pull-up control register 1 (PUCR1)
Bit
7
PUCR1
Initial value
0
Read/Write
R/W
PUCR1 controls whether the MOS pull-up of each of the port 1 pins P1
a PCR1 bit is cleared to 0, setting the corresponding PUCR1 bit to 1 turns on the MOS pull-up for
the corresponding pin, while clearing the bit to 0 turns off the MOS pull-up.
Upon reset, PUCR1 is initialized to H'00.
136
6
5
P1
P1
7
6
5
0
0
R/W
R/W
6
5
PCR1
PCR1
7
6
0
0
W
W
6
5
PUCR1
PUCR1
7
6
0
0
R/W
R/W
4
3
P1
P1
4
3
0
0
R/W
R/W
to P1
. If port 1 is read while PCR1
7
0
4
3
PCR1
PCR1
5
4
3
0
0
W
W
4
3
PUCR1
PUCR1
5
4
3
0
0
R/W
R/W
2
1
P1
P1
2
1
0
0
R/W
R/W
2
1
PCR1
PCR1
PCR1
2
1
0
0
W
W
to P1
functions as an
7
0
2
1
PUCR1
PUCR1
PUCR1
2
1
0
0
R/W
R/W
to P1
is on or off. When
7
0
0
P1
0
0
R/W
0
0
0
W
0
0
0
R/W
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