MC68HC908GR8 Datasheet, PDF (47/286 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Interrupts
4.3.1 Effects
An interrupt:
• Saves the CPU registers on the stack. At the end of the interrupt, the RTI instruction recovers the
CPU registers from the stack so that normal processing can resume.
• Sets the interrupt mask (I bit) to prevent additional interrupts. Once an interrupt is latched, no other
interrupt can take precedence, regardless of its priority.
• Loads the program counter with a user-defined vector address
•
•
•
5
4
STACKING ³
ORDER ₂
1
CONDITION CODE REGISTER
ACCUMULATOR
INDEX REGISTER (LOW BYTE)*
PROGRAM COUNTER (HIGH BYTE)
PROGRAM COUNTER (LOW BYTE)
1
2
3 _UNSTACKING
4
ORDER
5
•
•
•
$00FF DEFAULT ADDRESS ON RESET
*High byte of index register is not stacked.
Figure 4-3. Interrupt Stacking Order
MC68HC908GR8 • MC68HC908GR4 Data Sheet, Rev. 7
Freescale Semiconductor
47