Digital clock seconds counter — how to count 00 through 59? In the digital clock project, which counter configuration is typically used to count seconds from 00 to 59 for easy BCD display driving?

Introduction / Context:
Human-readable time uses decimal digits, so digital clocks usually build 00–59 with two cascaded counters: one for the ones place (0–9) and one for the tens place (0–5). Implementations that align with BCD simplify driving seven-segment displays and reduce glue logic.

Given Data / Assumptions:

• Seconds must roll 00→59, then back to 00.
• Ones digit cycles 0–9 (MOD-10 or BCD).
• Tens digit cycles 0–5 (MOD-6).

Concept / Approach:
Use a decade (BCD) counter for the ones digit so that decoding to a display is straightforward. Cascade its ripple-carry (or decoded terminal count) into a MOD-6 counter for the tens digit. When the ones digit reaches 9 and wraps to 0, the tens digit increments; when the tens digit reaches 5 and the ones digit wraps, the chain resets to 00, yielding 60 unique states (MOD-60 overall).

Step-by-Step Solution:

Verification / Alternative check:
Many reference designs implement seconds/minutes as BCD+MOD-6, while hours use MOD-12 or MOD-24. This modular approach is proven and minimizes decoding complexity.

Why Other Options Are Wrong:

• MOD-60 (single block) is less common as an off-the-shelf counter and makes display decoding harder.
• MOD-6 or BCD alone cannot span 00–59.
• Two MOD-30 blocks do not map cleanly to decimal digits.

Common Pitfalls:

• Forgetting to synchronize resets so 59 rolls to 00 without transient invalid display codes.

Final Answer:
BCD followed by a MOD-6