UPD784938 Datasheet, PDF (558/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 23 INTERRUPT FUNCTIONS
Figure 23-14. Examples of Servicing of Simultaneously Generated Interrupts
Main routine
EI
Interrupt request a (level 2)
Macro service request b (level 3)
Macro service request c (level 1)
Interrupt request d (level 1)
Interrupt request e (level 1)
Macro service request f (level 1)
Default priority order
a>b>c>d>e>f
Macro service request b servicing
Macro service request c servicing
Macro service request f servicing
Interrupt request d servicing
Interrupt request e servicing
Interrupt request a servicing
• When requests are generated
simultaneously, they are
acknowledged in the order starting
with macro service.
• Macro service requests are
acknowledged in default priority
order (b/c/f) (not dependent
upon the programmable priority
order).
• As interrupt requests are
acknowledged in high-to-low
priority level order, d and e are
acknowledged first.
• As d and e have the same
prority level, the interrupt
request with the higher default
priority, d, is acknowledged
first.
Remark “a” to “f” in the figure are arbitrary names used to differentiate between the interrupt requests and macro service
requests.
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Preliminary User’s Manual U13987EJ1V0UM00