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CHAPTER 12
INTERRUPT FUNCTIONS
Figure 12-8. Flowchart of Occurrence and Acknowledge Non-Maskable Interrupt
Start
WDTM4 = 1
(with watchdog timer
mode selected)
?
Yes
Overflow in
WDT
?
No
Interval timer
No
Yes
WDTM3 = 0
(with non-maskable
interrupt selected)
?
No
Reset processing
Yes
Interrupt request generation
WDT interrupt
servicing
?
No
Interrupt request reserve
Yes
Interrupt control
register unaccessed
?
No
Yes
Interrupt service start
WDTM : Watchdog timer mode register
WDT
: Watchdog timer
Figure 12-9. Non-Maskable Interrupt Request Acknowledge Timing
CPU Processing
Instruction
Instruction
WDTIF
An interrupt request generated during this period
is acknowledged at the timing indicated by .
WDTIF : Watchdog timer interrupt request flag
154
PSW and PC Save, Jump to
Interrupt Servicing Program
Interrupt Servicing