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Port Data Register A (PDRA)
Bit
Initial value
Read/Write
PDRA is an 8-bit register that stores data for port A pins PA
bits are set to 1, the values stored in PDRA are directly read, regardless of the actual pin states. If
port A is read while PCRA bits are cleared to 0, the pin states are read.
Upon reset, PDRA is initialized to H'F0.
Port Control Register A (PCRA)
Bit
Initial value
Read/Write
PCRA is an 8-bit register for controlling whether each of the port A pins PA
an input or output pin. Setting a PCRA bit to 1 makes the corresponding pin an output pin, while
clearing the bit to 0 makes the pin an input pin.
Upon reset, PCRA is initialized to H'F0.
PCRA is a write-only register. All bits are read as 1.
7
6
—
—
—
1
1
—
—
—
7
6
—
—
—
1
1
—
—
—
5
4
—
PA
1
1
—
R/W
to PA
3
5
4
—
PCRA
1
1
—
W
3
2
PA
PA
3
2
0
0
R/W
R/W
. If port A is read while PCRA
0
3
2
PCRA
PCRA
3
2
0
0
W
W
to PA
3
1
0
PA
1
0
0
0
R/W
1
0
PCRA
1
0
0
0
W
functions as
0
153
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