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Is new interrupt request keep until current interrupt is completed?

Latest Updated:10/10/2006

Question:

If a new interrupt request is generated while already servicing the same interrupt, is this new interrupt request retained until the current interrupt service routine is completed?

Answer:

The interrupt request bit(IR bit) goes to "1" when an interrupt request is generated and to "0" automatically when the program branches to the interrupt routine. If another interrupt request is generated (a new interrupt by the same source), after the program has branched to the interrupt routine and the IR bit has changed to "1", the new interrupt request will be retained. However, if another interrupt request is generated while the IR bit is still "1", IR will not be retained.
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