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What does the WFI instruction do in ARM processors?

easy📝 Conceptual Q1 of 15
ARM Architecture - Power Modes
What does the WFI instruction do in ARM processors?
APuts the processor into a low-power sleep mode until an interrupt occurs
BResets the processor to its initial state
CStarts executing the next instruction immediately
DDisables all interrupts permanently
Step-by-Step Solution
Solution:

  1. Step 1: Understand the purpose of WFI

    The WFI (Wait For Interrupt) instruction is designed to reduce power consumption by putting the processor into a sleep mode.

  2. Step 2: Identify what triggers wake-up

    The processor wakes up from this sleep mode only when an interrupt or event occurs.

  3. Final Answer:

    Puts the processor into a low-power sleep mode until an interrupt occurs -> Option A

  4. Quick Check:

    WFI function = Sleep until interrupt [OK]
Quick Trick: WFI means wait quietly until an interrupt wakes CPU [OK]
Common Mistakes:
  • Thinking WFI resets the CPU
  • Assuming WFI disables interrupts
  • Believing WFI executes next instruction immediately

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