GMS81C2020/GMS81C2120
Hyundai Micro Electronics
Example: Even though Timer1 interrupt is in progress,
INT0 interrupt serviced without any suspend.
Main Program
service
TIMER 1
service
TIMER1: PUSH
A
PUSH
PUSH
LDM
LDM
EI
X
INT0
service
Y
IENH,#80H
IENL,#0
;Enable INT0 only
;Disable other
;Enable Interrupt
enable INT0
disable other
EI
:
:
:
Occur
Occur
INT0
TIMER1 interrupt
:
:
:
enable INT0
enable other
LDM
LDM
POP
POP
POP
RETI
IENH,#0FFH ;Enable all interrupts
IENL,#0F0H
Y
X
A
In this example, the INT0 interrupt can be serviced without any
pending, even TIMER1 is in progress.
Because of re-setting the interrupt enable registers IENH,IENL
and master enable "EI" in the TIMER1 routine.
Figure 19-5 Execution of Multi Interrupt
70
preliminary
Nov. 1999 Ver 0.0
HYNIX [ HYNIX SEMICONDUCTOR ]
