M16C62_M Datasheet, PDF (488/615 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

Multiple Interrupts
Mitsubishi microcomputers
M16C / 62A Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
2.14.2 Multiple Interrupts Operation
The state when control branched to an interrupt routine is described below:
· The interrupt enable flag (I flag) is set to “0” (the interrupt is disabled).
· The interrupt request bit of the accepted interrupt is set to “0”.
· The processor interrupt priority level (IPL) is assigned to the same interrupt priority level as as
signed to the accepted interrupt.
Setting the interrupt enable flag (I flag) to “1” within an interrupt routine allows an interrupt request as-
signed a priority higher than the IPL to be accepted.
An interrupt request that is not accepted because of low priority will be held. If the condition following is
met when the REIT instruction returns the IPL and the interrupt priority is determined, then the interrupt
request being held is accepted.
Interrupt priority level of the interrupt request being held > Returned the IPL
Figure 2.14.6 shows the example of the multiple interrupts operation.
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