Electronics America 4-Bit Single-Chip Microcomputer User's Manual

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CHAPTER 6. INTERRUPT FUNCTIONS

(4) Pending interrupt execution

Reset

EI



➀



IECSI

IE0



<Main Program>

INT0



INTCSI

RETI

➁

RETI

<INTCSI Service Program>

<INT0 Service Program>

<Main Program>

➀ If INT0 and INTCSI are generated simultaneously (during execution of the same instruction), INT0, which

has the higher interrupt priority, is executed first (INTCSI is held pending).

➁ When the INT0 service program is ended by the RETI instruction, the pending INTCSI service program is

started.