M68HC08RG/AD
2
M68HC08 Family Reference Guide
MOTOROLA
Stacking
Figure 2. Interrupt Stack Frame
NOTE:
To maintain compatibility with the M6805 Family, H (the high byte of the index
register) is not stacked during interrupt processing. If the interrupt service
routine modifies H or uses the indexed addressing mode, it is
the user’s responsibility to save and restore it prior to returning.
IRQINT
PSHH
|
|Interrupt service routine
|
|
PULH
RTI
Figure 3. H Register Storage
CONDITION CODE REGISTER
ACCUMULATOR
INDEX REGISTER (LOW BYTE X)
(1)
PROGRAM COUNTER HIGH
1. High byte (H) of index register is not stacked.
PROGRAM COUNTER LOW
•
•
•
•
•
•
7
0
$00FF (DEFAULT ADDRESS
UNSTACKING
ORDER
STACKING
ORDER
5
4
3
2
1
1
2
3
4
5
ON RESET)
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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