GMS81004 Datasheet, PDF (37/101 Pages) Hynix Semiconductor – 8-BIT SINGLE CHIP MICROCOMPUTERS

Chapter 3. I/O PORT
3.3 PORT R2
3.3.1 PORT R2 Registers
REGISTERS
R2 I/O Data Direction Register
R2 Data Register
SYMBOL
R2DD
R2
R/W
W
R/W
RESET VALUE
00H
Undefined
ADDRESS
00C5H
00C4H
Table 3.3 Port R2 Registers
3.3.2 I/O Data Direction Register (R2DD)
bit
R2DD
initial value
R/W
7
R2DD7
0
W
6
R2DD6
0
W
5
R2DD5
0
W
4
R2DD4
0
W
3
R2DD3
0
W
2
R2DD2
0
W
1
R2DD1
0
W
0
R2DD0
0
W
<00C5H>
R2 Data Direction Register(R2DD) is 8-bit register, and can assign input state or output
state or output state to each bit. If R2DD is ¡È1¡È, port R2 is in the output state, and if
¡È0¡È, it is in the input state.
R2DD is write-only register. Since R2DD is initialized as ¡È00H¡È in reset state, the
whole port R2 becomes input state.
3.3.3 Data Register (R2)
bit
7
6
5
4
3
2
1
0
R2
R27
R26
R25
R24
R23
R22
R21
R20
<00C4H>
initial value
X
X
X
X
X
X
X
X
R/W ^R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R2 Data Register(R2) is 8-bit register to store data of port R2.
When setted as the output state by R2DD, and data is written in R2, data is output into
R2 pin. When setted as input state, input state of pin is read.
The initial value of R2 is unknown in reset state.
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