Freescale Semiconductor, Inc.
System Integration Module (SIM)
Program Exception Control
CLI
BACKGROUND
ROUTINE
LDA #$FF
INT1
PSHH
INT1 INTERRUPT SERVICE ROUTINE
PULH
RTI
INT2
PSHH
INT2 INTERRUPT SERVICE ROUTINE
PULH
RTI
Figure 6-11. Interrupt Recognition Example
6.6.1.2 SWI Instruction
The SWI instruction is a non-maskable instruction that causes an
interrupt regardless of the state of the interrupt mask (I bit) in the
condition code register.
NOTE: A software interrupt pushes PC onto the stack. A software interrupt does
not push PC – 1, as a hardware interrupt does.
6.6.2 Reset
All reset sources always have higher priority than interrupts and cannot
be arbitrated.
6.6.3 Break Interrupts
The break module can stop normal program flow at a software-
programmable break point by asserting its break interrupt output. (See
Section 7. Break Module (BRK).) The SIM puts the CPU into the break
state by forcing it to the SWI vector location. Refer to the break interrupt
MC68HC908RFRK2
MOTOROLA
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System Integration Module (SIM)
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