PD17225_15 Datasheet, PDF (47/86 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLER FOR SMALL GENERAL-PURPOSE INFRARED REMOTE CONTROL TRANSMITTER

µPD17225, 17226, 17227, 17228
7.3.2 Returning from interrupt processing routine
To return from an interrupt processing routine, use the RETI instruction.
Then the following processing is executed within an instruction cycle.
Loads contents of stack addressed by
stack pointer to program counter
Loads contents of interrupt
stack register to PSWORD
Increments value of stack pointer by 1
To enable an interrupt after the processing of an interrupt has been finished, the EI instruction must be
executed immediately before the RETI instruction.
Accepting the interrupt is enabled by the EI instruction after the instruction next to the EI instruction has been
executed. Therefore, the interrupt is not accepted between the EI and RETI instructions.
Data Sheet U12643EJ2V0DS00
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