NEC NEC PD78081(A), User Manual

Page: 205 / 274

182
CHAPTER 12 INTERRUPT FUNCTION
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
Figure 12-8. Flowchart from Non-Maskable Interrupt Request Generation to Acknowledgment
WDTM : Watchdog timer mode register
WDT : Watchdog timer
Figure 12-9. Non-Maskable Interrupt Request Acknowledge Timing
TMIF4 : Watchdog timer interrupt request flag
Instruction Instruction CPU Instruction
TMIF4
PSW and PC Save, Jump
to Interrupt Servicing
Interrupt Sevicing
Program
Interrupt requests which generate within this space are acknowledged with
↑
timing.