MC68HC908GP32 Datasheet, PDF (78/410 Pages) Motorola, Inc – M68HC08 Family of 8-bit microcontroller units (MCUs)

Freescale Semiconductor, Inc.
Resets and Interrupts
• 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 4-4. Interrupt Stacking Order
After every instruction, the CPU checks all pending interrupts if the I bit
is not set. If more than one interrupt is pending when an instruction is
done, the highest priority interrupt is serviced first. In the example shown
in Figure 4-5, if an interrupt is pending upon exit from the interrupt
service routine, the pending interrupt is serviced before the LDA
instruction is executed.
Technical Data
76
MC68HC908GP32•MC68HC08GP32 — Rev. 6
Resets and Interrupts
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