AN 846: Intel® Stratix® 10 Forward Error Correction

ID 683805
Date 7/02/2018
Public
Document Table of Contents

5.6.5. 64B/66B to 256B/257B Transcoder

If all four incoming blocks are data blocks:

  1. Remove the 2-bit headers of all four 66-bit data blocks.
  2. Append a header bit of 1 to the four 64-bit data payloads.
Figure 20. Incoming Data Blocks

If there is at least one control block among the four-incoming blocks:

  1. Remove the 2-bit headers of all four incoming 66-bit blocks
  2. Append a header bit of 0 to the four payloads of the four blocks.

    RS-FEC deletes the second 4-bit nibble in the block type field (BTF) of the first control block in a transcoded block. RS-FEC retains the first 4-bit nibble in the BTF of the first control block (indicating the type).

  3. Add the 4-bit header x1, x2, x3, or x4 following the overall header bit 0, where:
    • x1 = Data block
    • x2, x3, and x4 = Control block
Figure 21. Incoming Control Blocks