MC908GR16ACFA FREESCALE [Freescale Semiconductor, Inc], MC908GR16ACFA Datasheet - Page 135

• Manufacturer Part Number: MC908GR16ACFA
• Description: M68HC08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

example shown in
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.
See
13.3.2 Sources
The sources in
13.3.2.1 Software Interrupt (SWI) Instruction
The software interrupt (SWI) instruction causes a non-maskable interrupt.
13.3.2.2 Break Interrupt
The break module causes the CPU to execute an SWI instruction at a software-programmable break
point.
Freescale Semiconductor
Figure 13-5
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.
A software interrupt pushes PC onto the stack. An SWI does not push PC
– 1, as a hardware interrupt does.
Table 13-1
for a flowchart depicting interrupt processing.
Figure
13-4, if an interrupt is pending upon exit from the interrupt service routine, the
INT1
INT2
can generate CPU interrupt requests.
Figure 13-4
MC68HC908GR16A Data Sheet, Rev. 1.0
CLI
LDA
PSHH
PULH
RTI
PSHH
PULH
RTI
#$FF
.
Interrupt Recognition Example
NOTE
NOTE
INT1 INTERRUPT SERVICE ROUTINE
INT2 INTERRUPT SERVICE ROUTINE
BACKGROUND
ROUTINE
Interrupts
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