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What happens if setup and hold time is violated?
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. Violation in this case may cause incorrect data to be latched, which is known as a hold violation.
How do you resolve a violation violation?
Adding buffer / Inverter pairs /delay cells to the data path helps to fix the hold violation. Note: The hold violation path may have its start point or end point in other setup violation paths. So we have to take extra care before adding the buffer/delay.
How do you fix the hold time violations after the chip was fabricated?
There is no way to fix setup or hold violation after fabrication. One thing generally industry does is to sell the chip at lower operating frequency if there is setup violation. If there is a hold violation, chip will be thrown into garbage.
What is negative setup time?
As we know from the definition of setup time, setup time is a point on time axis which restrains data from changing after it. Data can change only before occurrence of setup timing point. Negative setup time: When setup time point occurs after clock edge, setup time is said to be negative.
What does violation of setup and hold time mean?
Any violation in this required time causes incorrect data to be latched and is known as a hold violation. For more information on the intra-flop aspects of setup and hold time, see Reference 1.
What does setup and hold time output mean?
So together they define a “setup-hold-window”, in which data has to remain stable. If the data changes/toggles within this window, the output is unpredictable or metastable. In your question data toggles within the setup window prior to the 6th clock edge, means the output is unpredictable.
When does data have to be valid for the hold time?
However, nothing is truly instantaneous, so the data must be valid for some finite amount of time around the clock edge. The time it must be fixed before the clock edge is called the setup time, and the time it must be fixed after the clock edge is called the hold time.
Why are the setup and hold times predictable?
If the data is stable between the setup and hold times, then the D latch manufacturer is guaranteeing that the output of the D latch will be predictable, what it says it will be in the data sheet.