UPD78F0411GA-GAM-AX Datasheet, PDF (451/564 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 17 INTERRUPT FUNCTIONS
Figure 17-8. Interrupt Request Acknowledgment Timing (Minimum Time)
CPU processing
××IF
(××PR = 1)
Instruction
Instruction
6 clocks
PSW and PC saved, _{Interrupt servicing}
jump to interrupt
servicing
program
××IF
(××PR = 0)
8 clocks
7 clocks
Remark 1 clock: 1/fCPU (fCPU: CPU clock)
Figure 17-9. Interrupt Request Acknowledgment Timing (Maximum Time)
CPU processing
××IF
(××PR = 1)
Instruction
25 clocks
Divide instruction
6 clocks
PSW and PC saved, _{Interrupt servicing}
jump to interrupt
servicing
program
××IF
(××PR = 0)
33 clocks
32 clocks
Remark 1 clock: 1/fCPU (fCPU: CPU clock)
17.4.2 Software interrupt request acknowledgment
A software interrupt acknowledge is acknowledged by BRK instruction execution. Software interrupts cannot be
disabled.
If a software interrupt request is acknowledged, the contents are saved into the stacks in the order of the program
status word (PSW), then program counter (PC), the IE flag is reset (0), and the contents of the vector table (003EH,
003FH) are loaded into the PC and branched.
Restoring from a software interrupt is possible by using the RETB instruction.
Caution Do not use the RETI instruction for restoring from the software interrupt.
User’s Manual U18698EJ1V0UD
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