153
Port Data Register A (PDRA)
Bit
7
6
5
4
3
2
1
0
—
—
—
—
PA
3
PA
2
PA
1
PA
0
Initial value
1
1
1
1
0
0
0
0
Read/Write
—
—
—
—
R/W
R/W
R/W
R/W
PDRA is an 8-bit register that stores data for port A pins PA
3
to PA
0
. If port A is read while PCRA
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
7
6
5
4
3
2
1
0
—
—
—
—
PCRA
3
PCRA
2
PCRA
1
PCRA
0
Initial value
1
1
1
1
0
0
0
0
Read/Write
—
—
—
—
W
W
W
W
PCRA is an 8-bit register for controlling whether each of the port A pins PA
3
to PA
0
functions as
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.