HMS87C1304A Datasheet, PDF (53/70 Pages) Hynix Semiconductor – CMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

HYUNDAI MicroElectronics
HMS87C1304A/HMS87C1302A
Main Program
service
TIMER 1
service
Occur
TIMER1 interrupt
enable INT0
disable other
EI
Occur
INT0
INT0
service
Example: Even though Timer1 interrupt is in progress,
INT0 interrupt serviced without any suspend.
TIMER1: PUSH
PUSH
PUSH
LDM
LDM
EI
:
:
:
A
X
Y
IENH,#80H
IENL,#0
;Enable INT0 only
;Disable other
;Enable Interrupt
:
:
:
enable INT0
LDM IENH,#0F0H
enable other
LDM IENL,#0E0H
POP Y
POP X
POP A
In this example, the INT0 interrupt can be serviced without any
y _{pending, even TIMER1 is in progress.}
Because of re-setting the interrupt enable registers IENH,IENL
r _{and master enable “EI” in the TIMER1 routine.}
Prelimina ^{Figure 15-5 Execution of Multi Interrupt}
RETI
;Enable all interrupts
Jan. 2001
Preliminary
53