CHAPTER 14 INTERRUPT FUNCTIONS
User’s Manual U14826EJ5V0UD
145
Figure 14-10. Interrupt Request Acknowledgment Timing (When Interrupt Request Flag Is Set at Last
Clock During Instruction Execution)
Saving PSW and PC, jump
to interrupt servicing
8 clocks
Interrupt
servicing
program
Clock
CPU
Interrupt
NOP
MOV A, r
If an interrupt request flag (
××
IF) is set at the last clock of the instruction, the interrupt acknowledgment processing
starts after the next instruction is executed.
Figure 14-10 shows an example of the interrupt acknowledgment timing for an interrupt request flag that is set at
the second clock of NOP (2-clock instruction). In this case, the MOV A, r instruction after the NOP instruction is
executed, and then the interrupt acknowledgment processing is performed.
Caution Interrupt requests will be held pending while interrupt request flag register 0 (IF0) or interrupt
mask flag register 0 (MK0) is being accessed.