188.8.131.52.1. Transmitter Byte Reversal
This feature is parameter-based, and creates no additional ports. If there is more than one channel in the design, all channels have TX byte reversal. To enable TX byte reversal, select the Enable TX byte reversal option in the Native PHY IP core.
You can implement soft logic to perform byte reversal for the Enhanced PCS.
Refer to the 8B/10B Encoder Byte Reversal Feature section for more information.