Renesas R8C/Tiny Series Software Manual page 275

Chapter 5 Interrupt
Interrupt request
generated
Reset
Time
Interrupt 1
Interrupt priority level = 3
Interrupt 2
Interrupt priority level = 5
Interrupt 3
Interrupt priority level = 2
Figure 5.6.1 Multiple interrupts
Main routine
I = 0
IPL = 0
I = 1
Interrupt 1
I = 0
IPL = 3
I = 1
REIT REIT
I = 1
IPL = 0
Interrupt 3
I = 0
IPL = 2
REIT
REIT
I = 1
IPL = 0
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Nesting
Multiple interrupts
Interrupt 2
I = 0
IPL = 5
REIT
REIT
I = 1
IPL = 3
Interrupt 3
Not acknowledged because
of low interrupt priority
Main routine instructions
are not executed.
I : Interrupt enable flag
IPL : Processor interrupt priority level
: Automatically executed.
: Be sure to set in software.
5.6 Multiple interrupts