M16C62_M Datasheet, PDF (489/615 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
Time
Interrupt request
generated
Reset
Interrupt 1
Interrupt priority level = 3
Main routine
I=0
IPL = 0
I=1
Interrupt 2
Interrupt priority level = 5
Interrupt 3
Interrupt priority level = 2
Nesting
Interrupt 1
I=0
IPL = 3
I=1
REIT
I=1
Multiple interrupts
Interrupt 2
I=0
IPL = 5
REIT
I=1
IPL = 3
Interrupt 3
Not acknowledged because
of low interrupt priority
IPL = 0
Interrupt 3
I=0
IPL = 2
Main routine instructions
are not executed.
REIT
I=1
IPL = 0
Figure 2.14.6. Example of the multiple interrupts operation
I : Interrupt enable flag
IPL : Processor interrupt priority level
: Automatically executed.
: Be sure to set in software.
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