s908ey8ad4cfjer Freescale Semiconductor, Inc, s908ey8ad4cfjer Datasheet - Page 103

• Manufacturer Part Number: s908ey8ad4cfjer
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

If the MODE bit is clear, the IRQ pin is falling-edge sensitive only. With MODE clear, a vector fetch or
software clear immediately clears the IRQ latch.
The IRQF bit in the ISCR register can be used to check for pending interrupts. The IRQF bit is not affected
by the IMASK bit, which makes it useful in applications where polling is preferred.
Use the BIH or BIL instruction to read the logic level on the IRQ pin.
Freescale Semiconductor
When using the level-sensitive interrupt trigger, avoid false interrupts by
masking interrupt requests in the interrupt routine.
YES
MC68HC908EY16 • MC68HC908EY8 Data Sheet, Rev. 10
INSTRUCTION?
INSTRUCTION?
INSTRUCTION
FROM RESET
INTERRUPT?
FETCH NEXT
I BIT SET?
Figure 9-2. IRQ Interrupt Flowchart
SWI
RTI
NO
NO
NO
NO
YES
YES
YES
NOTE
LOAD PC WITH INTERRUPT VECTOR
UNSTACK CPU REGISTERS
EXECUTE INSTRUCTION
STACK CPU REGISTERS
SET I BIT
IRQ Pin
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