
HYUNDAI MicroElectronics
52
Pin Function According to Operation Modes
PIN Single Chip Mode Microprocessor Mode
R30 I/O O Rd : external memory read strobe
R31 I/O O Wt : external memory write strobe
R32 I/O Programmable I/O Port O R/W :Read/Write cycle output pin of CPU
R33 I/O O C : timing signal output pin
R34 I/O O SYNC : op code fetch output pin of CPU
R35 I/O O BRK : bus acknowledge output pin of
CPU
R36 I/O I BRQ : bus request input pin of CUP
R37 I/O 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 Symbol R/W Address Initial Value
R4 I/O Direction Register R4DD W 00C9
H
0000 0000
R4 Port Data Register R4 R/W 00C8
H
Not initialized
Port R4 Mode Register PMR4 W 00D0
H
0000 0000
Interrupt Edge Select Register IEDS R/W 00F8
H
0000 0000
R4 PORT I/O DIRECTION REGISTER
R4 PORT DATA REGISTER
Port R4 output data
<00C8
H
>
R4
7
R47
6
R46
5
R45
4
R44
3
R43
2
R42
1
R41
0
R40
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Determines I/O of R4 port
0 : Input
1 : Output
<00C9
H
>
R4DD
7
R4DD7
6
R4DD6
5
R4DD5
4
R4DD4
3
R4DD3
2
R4DD2
1
R4DD1
0
R4DD0
W
W
W
W
W
W
W
W