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In a system using WFI, how can you ensure the processor wakes up only on specific events?

hard📝 Application Q9 of 15
ARM Architecture - Power Modes
In a system using WFI, how can you ensure the processor wakes up only on specific events?
AUse multiple WFI instructions in sequence
BDisable all interrupts before WFI
CConfigure interrupt controller to enable only desired interrupts
DReset the processor after WFI
Step-by-Step Solution
Solution:

  1. Step 1: Understand interrupt control

    Processor wakes on any enabled interrupt; controlling which interrupts are enabled controls wake-up.

  2. Step 2: Apply selective interrupt enabling

    By enabling only specific interrupts in the interrupt controller, CPU wakes only on those events.

  3. Final Answer:

    Configure interrupt controller to enable only desired interrupts -> Option C

  4. Quick Check:

    Selective interrupt enabling controls WFI wake-up [OK]
Quick Trick: Enable only needed interrupts to control wake-up [OK]
Common Mistakes:
  • Using multiple WFI to filter events
  • Disabling all interrupts prevents wake-up
  • Resetting processor unnecessarily

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