MC68HC908QY2 MOTOROLA [Motorola, Inc], MC68HC908QY2 Datasheet - Page 89

• Manufacturer Part Number: MC68HC908QY2
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

7.7.1.2 SWI Instruction
MOTOROLA
MC68HC908QY4•MC68HC908QT4•MC68HC908QY2•MC68HC908QT2•MC68HC908QY1•MC68HC908QT1
NOTE:
NOTE:
The LDA opcode is prefetched by both the INT1 and INT2
return-from-interrupt (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, software
should save the H register and then restore it prior to exiting the routine.
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.
A software interrupt pushes PC onto the stack. A software interrupt does
not push PC – 1, as a hardware interrupt does.
System Integration Module (SIM)
INT1
INT2
Figure 7-11
CLI
LDA
PSHH
PULH
RTI
PSHH
PULH
RTI
#$FF
.
Interrupt Recognition Example
INT1 INTERRUPT SERVICE ROUTINE
INT2 INTERRUPT SERVICE ROUTINE
System Integration Module (SIM)
BACKGROUND ROUTINE
Exception Control
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