MC68HC08XL36 Datasheet, PDF (60/362 Pages) Freescale Semiconductor, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Resets and Interrupts
Interrupts
Effects
An interrupt temporarily changes the sequence of program execution to
respond to a particular event. An interrupt does not stop the operation of
the instruction being executed, but begins when the current instruction
completes its operation.
An interrupt:
• Saves the CPU registers on the stack. At the end of the interrupt,
the RTI instruction recovers the CPU registers from the stack so
that normal processing can resume.
5
4
STACKING ₃
ORDER
2
1
•
•
•
CONDITION CODE REGISTER
ACCUMULATOR
INDEX REGISTER (LOW BYTE)*
PROGRAM COUNTER (HIGH BYTE)
PROGRAM COUNTER (LOW BYTE)
•
•
•
1
2
3 _UNSTACKING
4
ORDER
5
$00FF DEFAULT ADDRESS ON RESET
*High byte of index register is not stacked.
Figure 4. Interrupt Stacking Order
MC68HC08XL36
60
Resets and Interrupts
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