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CHAPTER 12 INTERRUPT FUNCTIONS
User’s Manual U15104EJ2V0UD
12.4.3 Software interrupt request acknowledgement operation
A software interrupt request is acknowledged by BRK instruction execution. Software interrupts cannot be
disabled.
If a software interrupt request is acknowledged, it is saved to the stack, the program status word (PSW) and program
counter (PC), in that order, the IE flag is reset to 0 and the contents of the vector tables (003EH and 003FH) are loaded
into the PC and branched.
Return from the software interrupt is possible with the RETB instruction.
Caution
Do not use the RETI instruction for returning from a software interrupt.
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