mc68hc908lb8 Freescale Semiconductor, Inc, mc68hc908lb8 Datasheet - Page 180

• Manufacturer Part Number: mc68hc908lb8
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

System Integration Module (SIM)
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.
17.5.1.2 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.
17.5.2 Reset
All reset sources always have equal and highest priority and cannot be arbitrated.
17.5.3 Break Interrupts
The break module can stop normal program flow at a software-programmable break point by asserting its
break interrupt output (see
forcing it to the SWI vector location. Refer to the break interrupt subsection of each module to see how
each module is affected by the break state.
180
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, software
should save the H register and then restore it prior to exiting the routine.
A software interrupt pushes PC onto the stack. A software interrupt does
not push PC – 1, as a hardware interrupt does.
INT1
INT2
19.2 Break Module
Figure 17-11
CLI
LDA
PSHH
PULH
RTI
PSHH
PULH
RTI
MC68HC908LB8 Data Sheet, Rev. 1
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Interrupt Recognition Example
(BRK)). The SIM puts the CPU into the break state by
NOTE
NOTE
INT1 INTERRUPT SERVICE ROUTINE
INT2 INTERRUPT SERVICE ROUTINE
BACKGROUND
ROUTINE
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