External Interrupt - Abov MC80F0304 User Manual

MC80F0304/08/16
interrupt can be serviced even if certain interrupt is in progress.
Main Program
service TIMER 1
service
enable INT0 INT0 service
disable other
EI
Occur Occur In this example, the INT0 interrupt can be serviced without any
TIMER1 interrupt INT0 pending, even TIMER1 is in progress. Because of re-setting the interrupt enable registers IENH,IENL
and master enable "EI" in the TIMER1 routine.
enable INT0 enable other
Figure 18-6 Execution of Multi Interrupt
Example: During Timer1 interrupt is in progress, INT0 interrupt :
serviced without any suspend. :
TIMER1: CLR1 PUSH T1IF A ;Clear Timer1 Request : :
PUSH PUSH X Y LDM LDM IENH,#0FFH ;Enable all interrupts IENL,#0FFH
LDM IENH,#80H ;Enable INT0 only POP Y
EI LDM IENL,#0 ;Disable other int. ;Enable Interrupt POP POP A X
: : RETI

18.4 External Interrupt

The external interrupt on INT0, INT1, INT2 and INT3 pins are The edge detection of external interrupt has three transition acti-
edge triggered depending on the edge selection register IEDS (ad- vated mode: rising edge, falling edge, and both edge.
dress 0EE H ) as shown in Figure 18-7 .
November 4, 2011 Ver 2.12 99