MC68HC708XL36 FREESCALE [Freescale Semiconductor, Inc], MC68HC708XL36 Datasheet - Page 63

• Manufacturer Part Number: MC68HC708XL36
• Description: HCMOS Microcontroller Unit
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

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MOTOROLA
NOTE:
After every instruction, the CPU checks all pending interrupts if the I bit
is not set. If more than one interrupt is pending when an instruction is
done, the highest priority interrupt is serviced first. If an interrupt is
pending upon exit from the 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, save the
H register and then restore it prior to exiting the routine.
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Freescale Semiconductor, Inc.
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Sets the interrupt mask (I bit) to prevent additional interrupts.
Once an interrupt is latched, no other interrupt can take
precedence, regardless of its priority.
Loads the program counter with a user-defined vector address.
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INT1
INT2
Figure 5
Resets and Interrupts
CLI
LDA
PSHH
PULH
RTI
PSHH
PULH
RTI
.
Interrupt Recognition Example
#$FF
INT1 INTERRUPT SERVICE ROUTINE
INT2 INTERRUPT SERVICE ROUTINE
Resets and Interrupts
MC68HC708XL36
BACKGROUND
ROUTINE
Interrupts
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