# Your question: What is Sta uncertainty clock?

Contents

Uncertainty. Clock uncertainty is the time difference between the arrivals of clock signals at registers in one clock domain or between domains. Pre-layout and Post-layout Uncertainty. Pre CTS uncertainty is clock skew, clock Jitter and margin. After CTS skew is calculated from the actual propagated value of the clock.

## What is set clock uncertainty?

Allows you to specify the expected clock setup or hold uncertainty associated with jitter, skew, and a guard band when performing setup and hold checks for clocks or clock-to-clock transfers. …

## How do you determine the uncertainty of a clock?

It can define for both setup and hold.

1. Set_clock_uncertainty –setup 0.2 [get_clocks clk_name1] …
2. Clock uncertainty for setup effectively reduces the available clock period by the specified amount as shown in fig. …
3. Pre CTS uncertainty = clock skew + jitter + margin.
4. CTS uncertainty = jitter + margin.

## What is clock latency and clock uncertainty?

Clock Skew between two sink pins is the the difference in the clock latency between them. … Clock uncertainty is the deviation of the actual arrival time of the clock edge with respect to the ideal arrival time. In ideal mode the clock signal can arrive at all clock pins simultaneously.

## What is clock uncertainty clock skew and clock jitter?

As an approximation, it is often useful to discuss the total clock timing uncertainty between two registers as the sum of spatial clock skew (the spatial differences in clock latency from the clock source), and clock jitter (meaning the non-periodicity of the clock at a particular point in the network).

## What is clock margin?

The timing margin is equal to the clock period T (period) minus the following factors: T (setup and hold): the sum of the minimum setup and hold times required to detect data (i.e., to resolve a 0 from a 1). The setup time is defined as positive before the falling edge of the clock.

## How do you set up uncertainty?

1. (5 cm ± . 2 cm) + (3 cm ± . 1 cm) =
2. (5 cm + 3 cm) ± (. 2 cm +. 1 cm) =
3. 8 cm ± . 3 cm.

## What is the difference between clock jitter and clock skew?

Clock skew is two different flip flops receive the clock signal at slightly different time due to difference in clock net length but clock jitter is on the same flip flop but the position of clock edge moves edge to edge due to some noise in oscillator.

## Why is uncertainty added in hold time?

hold time always less than setup time

at synthesis stage, more concern on reduce path timing, so setup uncertainty is more important to add margin to design. hold is easy fix, so less important, when do timing check, you should set a more consertive hold uncertainty .

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## What is clock skew in physical design?

Clock skew is a phenomenon in synchronous circuits in which the clock signal (sent from the clock circuit or source or clock definition point) arrives at different components at different times. due to. wire-interconnect length. temperature variations. capacitive coupling.

## What is OCV VLSI?

On-chip variation (OCV) is a recognition of the intrinsic variability of semiconductor processes and their impact on factors such as logic timing. … If the design passed these two tests, the chip could be considered to have met its timing constraints.

## What is skew and jitter?

JEDEC Standard 65 (EIA/JESD65) defines skew as “the magnitude of the time difference between two events that ideally would occur simultaneously” and explains jitter as the time deviation of a controlled edge from its nominal position.

## What is Slew in VLSI?

Transition Delay. Transition delay or slew is defined as the time taken by signal to rise from 10 %( 20%) to the 90 %( 80%) of its maximum value. This is known as “rise time”.

## What is jitter in clock?

Jitter is the timing variations of a set of signal edges from their ideal values. Jitters in clock signals are typically caused by noise or other disturbances in the system.

## What is launch clock and capture clock?

Launch clock path sees positive crosstalk delay so that data is launched late. … Capture clock path sees negative crosstalk delay so that data is captured by capture FF early.

## What is propagated clock?

Real clocks have sources. Real clocks can be ideal or propagated. An ideal clock incurs no delay through the clock network. A propagated clock is the opposite of an ideal clock. A virtual clock has no sources.

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