MC68HC705C8A Datasheet, PDF (57/222 Pages) Motorola, Inc – HCMOS Microcontroller Unit

FROM
RESET
Interrupts
Interrupt Processing
YES
I BIT IN
CCR REGISTER
SET?
NO
EXTERNAL
YES
IRQ
INTERRUPT?
NO
TIMER
YES
INTERRUPT?
NO
CLEAR IRQ REQUEST LATCH
SCI
YES
INTERRUPT?
NO
SPI
YES
INTERRUPT?
NO
FETCH NEXT
INSTRUCTION
1. STACK PC, X, A, CCR
2. SET I BIT
3. LOAD PC WITH VECTOR
SWI: $1FFC–$1FFD
IRQ: $1FFA–$1FFB
TIMER: $1FF8–$1FF9
SCI: $1FF6–$1FF7
SPI: $1FF4–$1FF5
YES
SWI
INSTRUCTION?
NO
RTI
YES
INSTRUCTION?
RESTORE REGISTERS FROM STACK:
CCR, A, X, PC
NO
EXECUTE INSTRUCTION
Figure 4-5. Reset and Interrupt Processing Flowchart
MC68HC705C8A — Rev. 2.0
MOTOROLA
Interrupts
Technical Data
57