MC68HC908GP32 Datasheet, PDF (79/410 Pages) Motorola, Inc – M68HC08 Family of 8-bit microcontroller units (MCUs)

Freescale Semiconductor, Inc.
Resets and Interrupts
Interrupts
CLI
LDA #$FF
BACKGROUND
ROUTINE
INT1
PSHH
PULH
RTI
INT1 INTERRUPT SERVICE ROUTINE
INT2
PSHH
PULH
RTI
INT2 INTERRUPT SERVICE ROUTINE
Figure 4-5. Interrupt Recognition Example
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.
NOTE:
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.
MC68HC908GP32•MC68HC08GP32 — Rev. 6
MOTOROLA
Resets and Interrupts
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Technical Data
77