DisplayPort Intel® FPGA IP User Guide

ID 683273
Date 9/02/2022
Public

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5.2.4.2. DP2.0 (128B/132B Channel Coding)

The IP composes Link Layer Frames - consisting of a LLCP (Link Layer Control Packet), followed by 1024 MTPs (Multi-stream Transport Packets). Each DP2.0 MTP is 64 link symbol clocks in length, time-multiplexed to carry the data (video, MSA, secondary, blanking) streams. Additional symbols called PHY_SYNC symbols and Overhead Symbols are then inserted into the Link Layer Frames before being sent to the 128B/132B Logical PHY Layer for encoding.

The 128B/132B Encoding process (within the 128B/132B Encoding Layer) consists of:
  • Logical lane count (always 4) to physical lane count (1, 2, or 4) conversion
  • Intra Super Symbol Shifting: moving control symbols to the first of every super symbol
  • PHY_SYNC Generator: replaces PHY_SYNCs from the Link Layer with the appropriate one to be transmitted on the wire
  • Scrambling
  • CDI bit insertion: 4-bit during Link Training, 1-bit during regular operation
  • FEC Encoding
  • Precoding

This produces a 32/64-bit symbol sent to the Intel FPGA high-speed transceiver.

During Link Training, the Logical PHY Layer generates both the 128b/132b_TPS1 and 128b/132b_TPS2 symbols.

The DP2.0 source also supports Link Quality Test Procedures, including:
  • 128b/132b_TPS1 link training pattern (Nyquist pattern)
  • 12bb/132b_TPS2 link training pattern
  • PRBS7, PRBS9, PRBS11, PRBS15, PRBS23, PRBS31 pattern
  • Custom 264-bit repeating pattern
  • Square wave pattern

All patterns are as defined in the DP2.0 Specification UHBRx Link Quality Test Support.

Figure 15. DP2.0 (128B/132B Channel Coding)