CHAPTER 14 INTERRUPT FUNCTIONS
User’s Manual U14826EJ5V0UD
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Figure 14-5. Flowchart from Non-Maskable Interrupt Request Generation to Acknowledgment (INTWDT)
Start
WDTM4 = 1
(watchdog timer mode
is selected)
Interval timer
No
WDT
overflows
No
Yes
Reset processing
No
Yes
Yes
Interrupt request is generated
Interrupt servicing is started
WDTM3 = 0
(non-maskable interrupt
is selected)
WDTM: Watchdog timer mode register
WDT: Watchdog
timer
Figure 14-6. Timing of Non-Maskable Interrupt Request Acknowledgment
Instruction
Instruction
Saving PSW and PC, and
jump to interrupt servicing
Interrupt servicing
program
CPU processing
Non-maskable
interrupt request
Figure 14-7. Acknowledgment of Non-Maskable Interrupt Request
First interrupt servicing
RETI instruction
execution
Second interrupt servicing
RETI instruction
execution
NMI request
(second)
NMI request
(first)
Main routing