Digital clock AM/PM control: In the digital clock project, when the time is 11:59:59 and the tens-of-hours equals 1 with enable active, what happens to the AM/PM flip-flop on the next clock pulse?

Introduction / Context:A 12-hour digital clock needs an extra bit to indicate AM or PM. The AM/PM flip-flop changes state exactly at the 11:59:59 → 12:00:00 transition. Detecting this boundary in logic avoids accidental toggles at other times and ensures the display reflects morning/afternoon correctly.

Given Data / Assumptions:

• 12-hour format with an AM/PM flag.
• At 11:59:59, the next tick rolls hours to 12:00:00.
• Logic detects tens-of-hours=1 and other enables at the rollover boundary.

Concept / Approach:The AM/PM indicator must flip exactly once per 12 hours. The most straightforward trigger is the hour rollover from 11 to 12. Implementations commonly decode 11:59:59 or use a count-equals condition that asserts a toggle control for the AM/PM flip-flop on the next clock edge as hours advance to 12:00:00.

Step-by-Step Solution:

Verification / Alternative check:Simulating hours, minutes, and seconds counters will show AM/PM toggling only at the 11→12 rollover. Edge cases (12:59:59 → 1:00:00) do not toggle the AM/PM bit, confirming the decoding is correct.

Why Other Options Are Wrong:

• Set/Reset/Clear/Hold: These actions would force a particular state or no change; we need an alternation every 12 hours, which is a toggle.

Common Pitfalls:Incorrectly toggling at 12→1 transitions; double-toggling due to bounce-like decode hazards; missing synchronization so the flip-flop toggles off the correct, single clock edge.

Final Answer:Toggle