L- and H-Tile Transceiver PHY User Guide

ID 683621
Date 1/30/2024
Document Table of Contents

3.9.4. Skew Calculations

To calculate the maximum skew between the channels, the following parameters are used:

  • PMA to PCS datapath interface width (S)
  • Maximum difference in number of parallel clock cycles between deassertion of each channel's FIFO reset (N).

To calculate the channel skew, the following three scenarios are considered:

  • Non-bonded—Both the PMA and PCS are non-bonded. Skew ranges from 0 UI to [(S-1) + N*S] UI.
  • PMA bonding using x6 / x24 clock network—The PCS is non-bonded. Skew ranges from [0 to (N*S)] UI + x6/x24 clock skew.
  • PMA and PCS bonding using the x6 / x24 clock network—Skew = x6 / x24 clock skew.