I noticed this as well.
I was using an Altera tool for estimating best tap coefficients (PELE) and comparing these results with fast eye and noticed the swap.
Hopefully Hyperlynx can confirm.
By the way if you are using AMI models, I believe the the fast eye channel analyzer will not include it.
Thanks for confirming this problem.
Acctually, what I was trying to do is to run FastEye on a channel including Xilinx V-6 GTX IBIS-AMI models to get optimal Tap coefficients and then feed those settings into IBIS-AMI model to run IBIS-AMI channel analysis flow. In the FastEye analysis, it ignores AMI models and just uses IBIS models for analog front-end. I compared the channel pulse responses generated in both FastEye flow and IBIS-AMI flow, and they are the same. This means my above method is valid.
I am finding that the channel pulse responses from FastEye and IBIS-AMI appear to be doing the same thing, characterizing the passive channel only. My receiving device has an analog front end amplifier with some peaking at 3GHz, and the opportunity to add more peaking using equalization controls. This is all within the AMI code and will not effect either pulse response or FastEye tap selection.
That said, I am finding the FastEye tap selection quite useful. I am not able to invoke RX equalization at the datarate that I am running, and the FastEye selected taps give me a nicely opened eye.
I checked with the developer of this code and found that the indexing of the taps is reversed compared to many other notations. If you use the optimized taps within HyperLynx, the index order is consistent, but if you use the HyperLynx taps in another tool, or taps from another tool in HyperLynx, then you need to reverse the order of the taps. HyperLynx 8.2 will reverse this order to be consistent with common notation.
On the point of channel characterization, the simulation takes into account the driver and receiver IBIS models. It is a bit more than just the passive portion of the channel. The problem is that some IBIS AMI models move even the analog (traditional IBIS) effects into the compiled AMI model. In this case, the channel characterization cannot include all the effects of the driver and receiver.