Sage-Tips

How do I get rid of setup time violation?

So if we can reduce more cell delay in comparison to wire delay, the effective stage delay decreases.

1. Method 2 : Replace buffers with 2 Inverters place farther apart.
2. Method 3 : HVT swap.
3. Method 4 : Increase Driver Size or say increase Driver strength (also known as upsize the cell)
4. Method 5 : Insert Buffers.

How can you reduce setup violations in the placement stage?

Setup violations at placement stage can be fixed using the following ways:

1. Optimise data path with less depth as much as possible.
2. Have better drive strength cells in the data path.
3. Set the timing optimisation effort level to high (assuming congestion is under control and the run time trade off is reasonable).

What happens if setup 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 I remove a hold violation?

How to fix hold violations

1. Insert delay elements: This is the simplest we can do, if we are to decrease the magnitude of a hold time violation.
2. Reduce the drive strength of data-path logic gates: Replacing a cell with a similar cell of less drive strength will certainly add delay to data-path.

What if setup is failed after manufacturing of chip?

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 happens to the output of a flip-flop if there is a setup violation on the input?

If the input meets the setup and hold time requirements, then the output is essentially “guanranteed” to reflect the input; if it violates the setup time, the behavior is no longer guaranteed or fully predictable, as you say.

How do you fix setup violations in FPGA?

To address setup time violations, you can: Use larger/stronger cells to drive paths with high capacitance, which can reduce the time needed to transition on sluggish net. Adjust the skew of the clock to the start or endpoint of the path which is violating. (time borrowing).