Active-level designation for up/down counting Given a counter designation that specifies the active logic levels for counting direction, what does it mean if the notation states that the up count is active-LOW and the down count is active-HIGH?

Introduction / Context:
Many up/down counters have direction-control inputs whose active level determines the counting direction. Recognizing “active-LOW” or “active-HIGH” notation prevents wiring mistakes and logic inversions when designing control signals.

Given Data / Assumptions:

• One control input selects up or down counting.
• Active level indicates which logic level causes that action.
• Positive-logic system is assumed (0 = LOW, 1 = HIGH).

Concept / Approach:
“Active-LOW up count” means the counter increments when the up-control input is at logic 0. “Active-HIGH down count” means the counter decrements when the down-control input is at logic 1, or when the same direction line (with defined polarity) selects down mode at logic 1.

Step-by-Step Solution:

Verification / Alternative check:
Consult a truth table: check that the counter steps up when UP=0 and steps down when DOWN=1 (or when a single DIR line uses the stated polarity).

Why Other Options Are Wrong:

• Options a, c, d contradict the specified active-level conditions.

Common Pitfalls:
Ignoring active-LOW labels and assuming all controls are active-HIGH; forgetting required pull-ups/pull-downs.

Final Answer:
up count is active-LOW, the down count is active-HIGH