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CHAPTER 19 INTERRUPT FUNCTIONS
Figure 19-8. Non-Maskable Interrupt Request Generation to Acknowledge Flowchart
Start
WDTM4 = 1
(with watchdog timer
mode selected)?
Overflow in WDT?
WDT interrupt
servicing?
Interrupt
control register not
accessed?
Interval timer
No
Reset processing
No
Interrupt request generation
Start of interrupt servicing
Interrupt request held pending
No
No
No
Yes
Yes
Yes
Yes
Yes
WDTM: Watchdog timer mode register
WDT : Watchdog timer
WDTM3 = 0
(with non-maskable
interrupt selected)?
Figure 19-9. Non-Maskable Interrupt Request Acknowledge Timing
Instruction
Instruction
PSW and PC save, jump
to interrupt servicing
Interrupt servicing
program
CPU processing
WDTIF
Interrupt request generated during this interval is acknowledged at .
WDTIF: Watchdog timer interrupt request flag
Summary of Contents for mPD780973 Series
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