UPD17073 NEC, UPD17073 Datasheet - Page 78

• Manufacturer Part Number: UPD17073
• Description: 4-BIT SINGLE-CHIP MICROCONTROLLER WITH HARDWARE FOR DIGITAL TUNING SYSTEM
• Manufacturer: NEC

11.8 Exiting from Interrupt Service Routine
dedicated instruction “RETI” is used.
executed.
operation of each system register described in step (2) above.
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(1) The contents of the address stack register specified by the stack pointer are restored to the program counter.
(2) The contents of the interrupt stack are restored to the lower 1 bit of the bank register (BANK).
(3) The contents of the stack pointer are incremented by one.
To return to the service that was executed when the interrupt was accepted from the interrupt service routine, a
When this instruction is executed, the following processing is automatically executed in sequence:
The processing (1) through (3) above is executed in one instruction cycle during which the “RETI” instruction is
The only difference between the “RETI” and subroutine return instructions “RET” and “RETSK” is the restore
Caution If the contents of the program status word are saved in the program, its contents must be
restored to the program status word at the same time.
PD17072,17073