MC68HC908JL8 MOTOROLA [Motorola, Inc], MC68HC908JL8 Datasheet - Page 98

• Manufacturer Part Number: MC68HC908JL8
• Description: Motorola reserves the right to make changes without further notice to any products herein
• Manufacturer: MOTOROLA [Motorola, Inc]

System Integration Module (SIM)
Technical Data
98
NOTE:
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.
Freescale Semiconductor, Inc.
For More Information On This Product,
System Integration Module (SIM)
INT1
INT2
Go to: www.freescale.com
Figure 7-11
CLI
LDA
PSHH
PULH
RTI
PSHH
PULH
RTI
#$FF
.
Interrupt Recognition Example
INT1 INTERRUPT SERVICE ROUTINE
INT2 INTERRUPT SERVICE ROUTINE
MC68HC908JL8
Figure 7-11
BACKGROUND ROUTINE
MOTOROLA
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Rev. 2.0