HD64F3670 Datasheet, PDF (121/323 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

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
7
1

6
1

5
1

4
1

3
1

2 P22
0
R/W
1 P21
0
R/W
0 P20
0
R/W
Description
Reserved
These bits are always read as 1.
PDR2 stores output data for port 2 pins.
If 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
Bit Name TXD
Setting Value 0
1
Legend X: Don't care.
PCR2
PCR22
0
1
X
Pin Function
P22 input pin
P22 output pin
TXD output pin
P21/RXD pin
Register SCR3
Bit Name RE
Setting Value 0
1
Legend X: Don't care.
PCR2
PCR21
0
1
X
Pin Function
P21 input pin
P21 output pin
RXD input pin
Rev. 2.0, 03/02, page 97 of 298