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Rev. 1.0, 07/01, page 117 of 372
Bit Bit Name Initial Value R/W Description
7
6
5
4
3
−
−
−
−
−
−
−
−
−
−
−
−
−
−
−
Reserved
2
1
0
PCR22
PCR21
PCR20
0
0
0
W
W
W
When each of the port 2 pins P22 to P20 functions as an
general I/O port, setting a PCR2 bit to 1 makes the
corresponding pin an output port, while clearing the bit to 0
makes the pin an input port.
9.2.2
Port Data Register 2(PDR2)
PDR2 is a general I/O port data register of port 2.
Bit Bit Name Initial Value R/W Description
7
6
5
4
3
−
−
−
−
−
1
1
1
1
1
−
−
−
−
−
Reserved
These bits are always read as 1 and cannot be modified.
2
1
0
P22
P21
P20
0
0
0
R/W
R/W
R/W
PDR2 stores output data for port 2 pins.
PDR2 is read while PCR2 bits are set to 1, the value stored
in PDR2 is read. If PDR2 is read while PCR2 bits are
cleared to 0, the pin states are read regardless of the value
stored in PDR2.
9.2.3
Pin Functions
The correspondence between the register specification and the port functions is shown below.
P22/TXD pin
Register PMR1 PCR2
Bit Name TXD PCR22 Pin Function
Setting Value 0 0 P22 input pin
0 1 P22 output pin
1 X TXD output pin
Legend X:Don't care.