Flip-flop input classes: Inputs that cause the flip-flop output to change immediately, independent of the clock (for example, asynchronous set or reset), are called asynchronous. Evaluate the statement.

Introduction / Context:
Flip-flops may accept two categories of control: synchronous (sampled by the clock) and asynchronous (override the state regardless of the clock). Recognizing the difference is central to safe design and timing closure.

Given Data / Assumptions:

• Typical asynchronous pins: preset (set) and clear (reset).
• These pins dominate the internal state forcing Q = 1 or Q = 0.
• They are not qualified by the clock and can act at any time.

Concept / Approach:
Asynchronous control immediately forces the state; therefore, it must be deasserted synchronously (or safely) to avoid recovery/removal violations. Synchronous controls (like D, J/K) affect the state only on the active clock edge.

Step-by-Step Solution:

Verification / Alternative check:
Datasheets label these pins as asynchronous and specify recovery/removal times rather than setup/hold.

Why Other Options Are Wrong:

Common Pitfalls:
Asserting asynchronous signals near a clock edge without meeting recovery/removal; leaving async pins floating; assuming they are sampled by the clock.

Final Answer:
Correct