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Rev. 1.0, 07/01, page 54 of 372
Vector fetch
ø
Internal
address bus
Internal read
signal
Internal write
signal
(2)
Internal data bus
(16 bits)
Interrupt
request signal
(9)
(1)
Internal
processing
Prefetch instruction of
interrupt-handling routine
(1) Instruction prefetch address (Instruction is not executed. Address is saved as PC contents, becoming return address.)
(2)(4) Instruction code (not executed)
(3) Instruction prefetch address (Instruction is not executed.)
(5) SP – 2
(6) SP – 4
(7) CCR
(8) Vector address
(9) Starting address of interrupt-handling routine (contents of vector)
(10) First instruction of interrupt-handling routine
(3) (9)(8)(6)(5)
(4) (1) (7) (10)
Stack access
Internal
processing
Instruction
prefetch
Interrupt level
decision and wait for
end of instruction
Interrupt is
accepted
Figure 3-3 Interrupt Sequence