1.3.1 8b10b

The 8b10b mode supports the encoder and decoder only for interface widths of 16, 32, and 64 bits at the PMA.

The following features are supported in the 8b10b:

• Transmit encoding.
• Transmit disparity forcing.
• Transmit disparity adaptation, which operates in two sub-modes—1 Gbps IEEE 802.3 mode and Fiber Channel mode.
• Receiver symbol alignment using CDR slip mechanism.
• Deterministic latency through the 8B10B transmitter and receiver data paths.
• Receiver decoding.
• Electable fabric width (on transceiver level) of two, four, or eight octets per clock beat.

The 8b10b trans-coder is protocol independent, in other words, it does not include a protocol-specific word aligner or word alignment state machine. Comma-detection is supported in this mode. The serial data must be aligned to comma-alignment boundaries before being used as parallel data. Without proper alignment, the incoming 8b10b data does not decode correctly. The comma character (K28.5) is usually used for alignment purposes as its 10-bit code is guaranteed not to occur elsewhere in the encoded bit stream.