XC68HC08KH12 Motorola, XC68HC08KH12 Datasheet - Page 75

• Manufacturer Part Number: XC68HC08KH12
• Description: MICROCONTROLLER
• Manufacturer: Motorola

MC68HC(7)08KH12
MOTOROLA
NOTE:
—
Rev. 1.0
set, the SIM proceeds with interrupt processing; otherwise, the next
instruction is fetched and executed.
If more than one interrupt is pending at the end of an instruction
execution, the highest priority interrupt is serviced first.
demonstrates what happens when two interrupts are pending. If an
interrupt is pending upon exit from the original interrupt service routine,
the pending interrupt is serviced before the LDA instruction is executed.
The LDA opcode is prefetched by both the INT1 and INT2 RTI
instructions. However, in the case of the INT1 RTI prefetch, this is a
redundant operation.
To maintain compatibility with the M6805 Family, the H register is not
pushed on the stack during interrupt entry. If the interrupt service routine
modifies the H register or uses the indexed addressing mode, software
should save the H register and then restore it prior to exiting the routine.
INT1
INT2
System Integration Module (SIM)
Figure 7-11
CLI
LDA
PSHH
PULH
RTI
PSHH
PULH
RTI
#$FF
.
Interrupt Recognition Example
INT1 INTERRUPT SERVICE ROUTINE
INT2 INTERRUPT SERVICE ROUTINE
System Integration Module (SIM)
Advance Information
Figure 7-11
BACKGROUND ROUTINE
Exception Control
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