GMS81508A Datasheet, PDF (57/91 Pages) Hynix Semiconductor – USERS MANUAL

HYUNDAI MicroElectronics

Pin Function According to Operation Modes
PIN
Single Chip Mode
R30
I/O
R31
I/O
R32
I/O Programmable I/O Port
R33
I/O
R34
I/O
R35
I/O
R36
I/O
R37
I/O
Microprocessor Mode
O Rd : external memory read strobe
O Wt : external memory write strobe
O R/W :Read/Write cycle output pin of CPU
O C : timing signal output pin
O SYNC : op code fetch output pin of CPU
O BRK : bus acknowledge output pin of
CPU
I BRQ : bus request input pin of CUP
I HALT : CPU halt input pin
3.5. R4 PORT
R4 Port is composed of 8bit programmable I/O port and this port are double functional pin.
Register Name
R4 I/O Direction Register
R4 Port Data Register
Port R4 Mode Register
Interrupt Edge Select Register
Symbol
R4DD
R4
PMR4
IEDS
R/W
W
R/W
W
R/W
Address
00C9_H
00C8_H
00D0_H
00F8_H
Initial Value
0000 0000
Not initialized
0000 0000
0000 0000

R4 PORT I/O DIRECTION REGISTER
R4DD
<00C9_H>
W
W
W
W
W
W
W
W
7
6
5
4
3
2
1
0
R4DD7 R4DD6 R4DD5 R4DD4 R4DD3 R4DD2 R4DD1 R4DD0

R4 PORT DATA REGISTER
Determines I/O of R4 port
0 : Input
1 : Output
R4
<00C8_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
R47 R46 R45 R44 R43 R42 R41 R40
Port R4 output data
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