What do you mean by clock skew?

Clock Skew is the time difference between the arrival of the same edge of a clock signal at the Clock pin of the capture flop and launch flop. Any signal’s journey from one location to another requires time. Clock latency is the length of time it takes for a clock signal to get from its source to the clock pin of a specific flip-flop. The disparity between a set of flops’ capture clock and launch clock latency is another name for clock skew.

“Clock skew is also known as clock uncertainty”

What is positive, negative, and zero clock skew?

#Even if the clock signal originates from the same source, in synchronous circuits, it may arrive at various components at various times. Clock skew may be caused by changes in temperature, capacitor decoupling, wire connector length, or material flaws.

Positive Clock Skew

When the transmitting source receives the clock tick before the receiver, it is known as the positive clock skew. The use of positive clock skew enhances the operating frequency and makes the hold time tougher.

Negative Clock Skew

When the transmitting source receives the clock tick after the receiver receives it, this is known as the negative clock skew. The negative skew
decreases operating frequency.

Zero Clock Skew

When there is synchronization between transmitter and receiver for clock arrival, it is known as zero clock skew.

How does the clock skew violate setup and hold time constraints?

#The clock skew can cause two types of violations:  Setup violation and Hold time violation

When the clock signal travels at a slower speed than required, then the integrity and synchronization between source and destination are destroyed, it is known as a hold time violation. When the clock signal travels faster, the destination receives the clock tick before the source, which causes the violation. As the data reaches late.

How does a pseudo-static register address the challenges posed by clock overlap?

A pseudo-static register combines static and dynamic storage approaches depending on the clock’s state. During non-overlapping times, it operates in a high-impedance state with an open feedback loop, preventing issues related to clock overlap. This approach helps maintain data integrity while avoiding excessive leakage.

Why is it essential to keep the nonoverlap time (tnon_overlap) between clock signals large enough to avoid clock overlap?

Keeping tnon_overlap sufficiently large ensures that clock signals do not overlap, preventing race conditions and other timing-related problems. If the nonoverlap time is too short, there is a risk of clock overlap occurring, which can lead to unpredictable behavior in the circuit.