Why hold is checked at the same edge?

The level must be stable for some hold time after each edge in order to be captured correctly. This is independent of clock period and hence is measured off of the same edge, except with parameters that are the opposite of that for the setup time. In this case, shortest clock net delays, earliest jitter, etc.

What is setup and hold timing check?

Setup and hold checks are the most common types of timing checks used in timing verification. Synchronous inputs (e.g. D) have Setup, Hold time specification with respect to the clock input. These checks specify that the data input must remain stable for a specified interval before and. after the clock input changes.

What is setup check?

What is meant by setup check: Setup check ensures that the design transitions to the next state as desired through the state machine design. Mostly, the setup check is at next active clock edge relative to the edge at which data is launched. Let us call this as default setup check.

What is setup hold time?

Setup time is the amount of time required for the input to a Flip-Flop to be stable before a clock edge. Hold time is similar to setup time, but it deals with events after a clock edge occurs. Hold time is the minimum amount of time required for the input to a Flip-Flop to be stable after a clock edge.

Why is setup calculated at next clock edge?

Setup check: Setup check refers to the condition in which data launched at one clock edge should get captured at the next clock edge so that the state machine functionality is preserved and the state machine transitions smoothly from one state to the next.

Can clock jitter effect set and hold time?

Since the jitter affects the clock delay of the circuit and the time the clock is available at sync points, setup and hold of the path elements are affected by it. Depending on whether the jitter causes to clock to be slower or faster, there can be setup hold or setup violations in an otherwise timing clean system.

Why is setup and hold time required?

Setup and hold checks in a design: Basically, setup and hold timing checks ensure that a data launched from one flop is captured at another properly. Setup check ensures that the data is stable before the setup requirement of next active clock edge at the next flop so that next state is reached.

Why do we have setup and hold time?

Why is this. Setup and hold time is the time wher the clock may not recognize the date. Anything in between setup and hold time is an unstable reagion where the part could read the wrong data. Setup time is the amount of time the data needs to arrive before the clock so the clock will catch it.

How do you fix setup and hold violations in physical design?

8 Ways To Fix Setup violation:

1. Adding inverter decreases the transition time 2 times then the existing buffer gate.
2. As such cell delay of 1 buffer gate ≈ cell delay of 2 Inverter gate.
3. So stage delay (cell delay + wire delay) in case of single buffer < stage delay in case of 2 inverter in the same path.

Why setup time is required?

It is here that we introduce SETUP and HOLD time. Setup time is defined as the minimum amount of time before the clock’s active edge that the data must be stable for it to be latched correctly. Any violation may cause incorrect data to be captured, which is known as setup violation.

How does jitter effect setup and hold paths?

In other words, jitter in clock period makes the setup timing more tight. Or it decreases setup slack for single cycle timing paths. Effect of clock jitter on hold slack for single cycle paths: Going on the same grounds as setup slack, hold check will be from edge 1 -> edge 1 only.

Why is jitter not in hold?

Re: Why hold is not affected be jitter? Because jitter is based on different edges of the clock and hold is analyzed on the same edge of the clock.

Why is the hold checked with the same clock edge?

This is because the hold is checked with the same clock edge, and setup with the next clock edge. From the figure above,assuming ideal clock, there is a window of time which is between the minimum required (ThFF2) and the maximum allowed (Clock period – TsFF2) that the timing path can correctly have.

What is clock gating setup check and hold check?

Setup check: The clock gating setup check is used to ensure the EN is are stable before the clock is active. A clock gating setup failure can cause a glitch at the leading edge of the clock. 2. clock gating hold check is used to ensure that the EN is stable while the clock is active.

What is the difference between setup check and hold check?

As is shown, setup check occurs at the next rising edge and hold check occurs at the same edge corresponding to the launch clock edge. For this case setup timing equation cab be given as: Also, we show below the data valid and invalid windows. From this figure,

How datadata is launched on negative edge of the clock?

Data is launched on negative edge of the clock, setup is checked on the next rising edge and hold on previous rising edge of the clock. Figure 8 below shows the setup and hold checks in the form of waveforms.