NEC uPD78P078 - Manual (Page 514)

514
CHAPTER 22 INTERRUPT FUNCTIONS
Figure 22-10. Flowchart from Non-Maskable Interrupt Generation to Acknowledge
WDTM4 = 1
(with watchdog timer
mode selected)?
Overflow in WDT?
WDTM3 = 0
(with non-maskable
interrupt selected)?
Interrupt request generation
WDT interrupt servicing?
Interrupt control
register unaccessed?
Interrupt
service start
Interrupt request
held pending
Reset processing
Interval timer
Start
No
Yes
Yes
No
Yes
No
Yes
No
Yes
No
WDTM : Watchdog timer mode register
WDT : Watchdog timer
Figure 22-11. Non-Maskable Interrupt Request Acknowledge Timing
TMIF4 : Watchdog timer interrupt request flag
Instruction
The interrupt request generated in this period is acknowledged at timing.
Instruction CPU Instruction
TMIF4
PSW and PC Save, Jump
to Interrupt Servicing Interrupt Sevicing
Program