Flowchart From Non-Maskable Interrupt Request Generation To Acknowledgment (Intwdt) - NEC PD789860 User Manual

Figure 14-5. Flowchart from Non-Maskable Interrupt Request Generation to Acknowledgment (INTWDT)
Figure 14-6. Timing of Non-Maskable Interrupt Request Acknowledgment
CPU processing Instruction
Non-maskable
interrupt request
Figure 14-7. Acknowledgment of Non-Maskable Interrupt Request
NMI request
142
CHAPTER 14 INTERRUPT FUNCTIONS
Start
WDTM4 = 1
(watchdog timer mode
is selected)
Yes
WDT
overflows
Yes
WDTM3 = 0
(non-maskable interrupt
is selected)
Yes
Interrupt request is generated
Interrupt servicing is started
WDTM: Watchdog timer mode register
WDT: Watchdog timer
Instruction
Main routing
NMI request
(first)
User's Manual U14826EJ5V0UD
No
Interval timer
No
No
Reset processing
Saving PSW and PC, and
jump to interrupt servicing
First interrupt servicing
(second)
RETI instruction
execution
Second interrupt servicing
RETI instruction
execution
Interrupt servicing
program