How to Avoid Glitches When Comparing Signals

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1. Compare equal signals that have glitches
If, for example, you have signals A and B that are supposed to be equal. You also have glitches in signal B. How do you avoid glitches in B? By using the continuous assignment, you can avoid glitches in a signal.
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If you need to compare two signals it’s easy to do so using XOR (Tips & Tricks 15. Check if signals are equal using XOR).
This define will compare signals A and B, detect the glitches in B, and the checker will ignore them.

 
How_to_avoid_glitches_when_comparing_signals

What this define is doing is comparing signal A with signal B, while using continuous assign statements to delay the change in compare_xor_chk, and avoiding the glitch. We need the id if we want to have multiple instances of this define.


2. Compare equal signals that have a small delay

Example: If B is equal to A and is delayed by 0.1ns, then we work on the assign with delay >0.1 then the compare_xor_chk will stay low and the check will pass.

 

How_to_avoid_glitches_when_comparing_signals

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