Validating the clear (CLR) input on a binary counter How should you correctly test the CLR function so that all flip-flops return to the defined reset state when the CLR pin is driven to its specified active level?

Introduction / Context:
Most counter ICs provide an asynchronous clear (CLR) pin that forces all internal flip-flops to a known reset state regardless of the clock. A correct bench test must exercise the CLR pin at its specified active level and confirm the outputs return to the documented reset code.

Given Data / Assumptions:

• CLR is asynchronous and overrides counting.
• Active level (HIGH or LOW) depends on the device datasheet and pin marking (e.g., CLR, CLR̅).
• Reset state is defined; for binary up-counters it is typically all zeros.

Concept / Approach:
To test CLR, assert the pin at its active level and directly observe outputs. Since the function is asynchronous, clocking is unnecessary during the assertion. Release CLR and verify normal counting resumes.

Step-by-Step Solution:

Verification / Alternative check:
Use a logic analyzer or LEDs on Q pins to visually confirm synchronous behavior resumes post-clear starting at the reset code.

Why Other Options Are Wrong:
Grounding or tying to Vcc without regard to active level may be incorrect for devices with opposite polarity. Expecting “toggling” during an asserted CLR is wrong because clear forces a static state.

Common Pitfalls:
Misreading an overbar on CLR̅ and driving the wrong polarity; failing to allow for propagation time before reading Q pins after assertion.

Final Answer:
apply the active level to the CLR input and check all of the Q outputs to see if they are all in their reset state