1.
Port data register 3 (PDR3)
PDR3 is an 8-bit register that stores data for port 3 pins P3
7
to P3
0
. If port 3 is read while PCR3
bits are set to 1, the values stored in PDR3 are read, regardless of the actual pin states. If port 3 is
read while PCR3 bits are cleared to 0, the pin states are read.
Upon reset, PDR3 is initialized to H'00.
2.
Port control register 3 (PCR3)
PCR3 is an 8-bit register for controlling whether each of the port 3 pins P3
7
to P3
0
functions as an
input pin or output pin. Setting a PCR3 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 PCR3 and in PDR3 are valid only
when the corresponding pin is designated in PMR3 as a general I/O pin.
Upon reset, PCR3 is initialized to H'00.
PCR3 is a write-only register, which is always read as all 1s.
Bit
Initial value
Read/Write
7
PCR3
0
W
6
PCR3
0
W
5
PCR3
0
W
4
PCR3
0
W
3
PCR3
0
W
0
PCR3
0
W
2
PCR3
0
W
1
PCR3
0
W
2
1
0
5
4
3
7
6
Bit
Initial value
Read/Write
7
P3
0
R/W
6
P3
0
R/W
5
P3
0
R/W
4
P3
0
R/W
3
P3
0
R/W
0
P3
0
R/W
2
P3
0
R/W
1
P3
0
R/W
2
1
0
5
4
7
6
3
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