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Preliminary
MC80F0104/0204
Mar. 2005 Ver 0.2
85
be serviced even if certain interrupt is in progress.
Figure 18-6 Execution of Multi Interrupt
Example:
During Timer1 interrupt is in progress, INT0 in-
terrupt serviced without any suspend.
TIMER1: PUSH
A
PUSH
X
PUSH
Y
LDM
IENH,#80H
;
Enable INT0 only
LDM
IENL,#0
;
Disable other int.
EI
;
Enable Interrupt
:
:
:
:
:
:
LDM
IENH,#0FFH
;
Enable all interrupts
LDM
IENL,#0FFH
POP
Y
POP
X
POP
A
RETI
enable INT0
TIMER 1
service
INT0
service
Main Program
service
Occur
TIMER1 interrupt
Occur
INT0
EI
disable other
enable INT0
enable other
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.
Содержание MC80C0104
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