Datasheet

Table Of Contents
Section 9 I/O Ports
Rev. 2.00 Jul. 04, 2007 Page 187 of 692
REJ09B0309-0200
9.9.1 Port Data Register A (PDRA)
PDRA is a register that stores data of port A.
Bit Bit Name
Initial
Value
R/W Description
7 to 4 All 1 Reserved
These bits are always read as 1 and cannot be
modified.
3
2
1
0
PA3
PA2
PA1
PA0
0
0
0
0
R/W
R/W
R/W
R/W
If port A is read while PCRA bits are set to 1, the values
stored in PDRA are read, regardless of the actual pin
states. If port A is read while PCRA bits are cleared to
0, the pin states are read.
9.9.2 Port Control Register A (PCRA)
PCRA selects inputs/outputs in bit units for pins to be used as general I/O ports of
port A.
Bit Bit Name
Initial
Value
R/W Description
7 to 4 All 1 Reserved
These bits are always read as 1 and cannot be
modified.
3
2
1
0
PCRA3
PCRA2
PCRA1
PCRA0
0
0
0
0
W
W
W
W
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.
PCRA is a write-only register. These bits are always
read as 1.