UPD78F1502AGK-GAK-AX Datasheet, PDF (782/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 19 INTERRUPT FUNCTIONS
Figure 19-15. Interrupt Request Acknowledgment Timing (Minimum Time)
CPU processing
Instruction
Instruction
6 clocks
PSW and PC saved, _{Interrupt servicing}
jump to interrupt
servicing
program
××IF
9 clocks
Remark 1 clock: 1/fCLK (fCLK: CPU clock)
Figure 19-16. Interrupt Request Acknowledgment Timing (Maximum Time)
CPU processing
Instruction
6 clocks
RET instruction
6 clocks
PSW and PC saved,
jump to interrupt
servicing
Interrupt servicing
program
××IF
14 clocks
Remark 1 clock: 1/fCLK (fCLK: CPU clock)
19.4.2 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 (0007EH,
0007FH) 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.
R01UH0004EJ0501 Rev.5.01
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Jun 20, 2011