GMS81508A Datasheet, PDF (56/91 Pages) Hynix Semiconductor – USERS MANUAL

GMS81508/16

Pin Function According to Operation Modes
PIN
Single Chip Mode
R20/A8
I/O
R21/A9
I/O
R22/A10
I/O Programmable I/O Port
R23/A11
I/O
R24/A12
I/O
R25/A13
I/O
R26/A14
I/O
R27/A15
I/O
Microprocessor Mode
O
O
O upper 8bit address of External Memory
O for CPU.
O
O
O
O
3.4. R3 PORT
R3 Port is composed of 8-bit programmable I/O pin.
Register Name
R3 I/O Direction Register
R3 PORT Data Register
Symbol
R3DD
R3
R/W
W
R/W
Address
00C7_H
00C6_H
Initial Value
0000 0000
Not initialized

R3 PORT I/O DIRECTION REGISTER
R3DD
<00C7_H>
W
W
W
W
W
W
W
W
7
6
5
4
3
2
1
0
R3DD7 R3DD6 R3DD5 R3DD4 R3DD3 R3DD2 R3DD1 R3DD0

R3 PORT DATA REGISTER
Determines I/O of R3 port
0 : Input
1 : Output
R3
<00C6_H>
R/W R/W R/W R/W R/W R/W R/W R/W
7
6
5
4
3
2
1
0
R37 R36 R35 R34 R33 R32 R31 R30
Port R3 output data
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