170
CHAPTER 12 INTERRUPT FUNCTIONS
User’s Manual U15104EJ2V0UD
Figure 12-10. Interrupt Request Acknowledgement Processing Algorithm
××
IF:
Interrupt request flag
××
MK: Interrupt mask flag
××
PR: Priority specification flag
IE:
Flag controlling acknowledging maskable interrupt request (1 = enable, 0 = disable)
ISP:
Flag indicating priority of interrupt currently being serviced (0 = interrupt with high priority serviced,
1 = interrupt request is not acknowledged, or interrupt with low priority serviced)
Start
××
IF = 1?
××
MK = 0?
××
PR = 0?
Any
simultaneously
generated
××
PR = 0
interrupt requests?
Any
simultaneously
generated high-priority
interrupt requests ?
IE = 1?
ISP = 1?
Vectored interrupt
servicing
Interrupt request
pending
Interrupt request
pending
Interrupt request
pending
Interrupt request
pending
Interrupt request
pending
Interrupt request
pending
Interrupt request
pending
Vectored interrupt
servicing
Any high-
priority interrupt request among
simultaneously generated
××
PR = 0 interrupts?
IE = 1?
Yes (High priority)
Yes
No
Yes
No
No
No
Yes (interrupt request
generation)
No
Yes
No (Low priority)
Yes
Yes
No
Yes
Yes
No
No
Содержание mPD178053
Страница 2: ...2 User s Manual U15104EJ2V0UD MEMO ...