MC68HC908GZ8 Datasheet, PDF (54/344 Pages) Motorola, Inc – Microcontrollers

Resets and Interrupts
CLI
LDA #$FF
INT1
PSHH
PULH
RTI
BACKGROUND
ROUTINE
INT1 INTERRUPT SERVICE ROUTINE
INT2
PSHH
INT2 INTERRUPT SERVICE ROUTINE
PULH
RTI
Figure 4-4. Interrupt Recognition Example
NOTE:
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.
See Figure 4-5 for a flowchart depicting interrupt processing.
4.3.2 Sources
The sources in Table 4-1 can generate CPU interrupt requests.
Data Sheet
54
Resets and Interrupts
MC68HC908GZ8
Freescale Semiconductor