Digital clock HDL design detail: In a typical digital clock implemented in HDL, a 1 pulse-per-second (1 pps) signal is used as the synchronous clock that drives all counter stages, which are synchronously cascaded. Assess this statement.

Introduction / Context:Digital clocks increment seconds once every second, then roll over to minutes and hours. In HDL (VHDL/Verilog) implementations, a clean 1 pps tick derived from a crystal time base or external reference is often used to clock the synchronous counters that hold seconds, minutes, and hours.

Given Data / Assumptions:

• A time base (e.g., 32.768 kHz crystal) is divided down to 1 Hz (1 pps).
• Seconds, minutes, and hours counters are synchronous (all flip-flops share the same clock edge).
• Carry/enable logic creates next-stage increments at the correct rollovers (59→00 for seconds/minutes; 23→00 for hours in a 24-hour clock).

Concept / Approach:Using a single synchronous clock simplifies timing closure and eliminates ripple delays inherent in asynchronous chains. The 1 pps tick serves as the sole clock, while enable conditions inside each counter determine whether a given stage increments on that tick (for example, minutes increment when seconds = 59 then wraps).

Step-by-Step Solution:

Verification / Alternative check:Simulation waveforms show all counters advancing on the same clock edge; synthesis reports confirm a single global clock domain, reducing skew problems compared to ripple chains.

Why Other Options Are Wrong:

Common Pitfalls:Deriving 1 pps with asymmetric duty or jitter; mixing clock domains inadvertently; failing to debounce external references.

Final Answer:Correct