Receive FEC-Only Operation - 1.2 English

Versal ACAP Integrated 600G Interlaken with FEC Subsystem Product Guide (PG371)

Document ID
PG371
Release Date
2023-01-19
Version
1.2 English

The following diagrams show several representative RX transactions on the FEC-only interface. On the databus, the subscript attached to the CW text is a representation of the codeword sequence number.

The 100 Gb/s diagrams show only the first FEC instance, however, they are representative of the behavior for all FEC instances. The 50 Gb/s diagrams show only the first slice of the first FEC instance, however, they are representative of the behavior for all FEC slices of all FEC instances.

User logic pulses rx_fec0_slice0_din_start in the same clock cycle as the data containing the start of codeword. In subsequent contiguous clock cycles, the remaining codeword data must be applied until the end of the codeword is reached. In the cycle following the end of codeword, the user logic may start a new codeword by pulsing the rx_fec0_slice0_din_start again.

The following figure shows the case of user logic providing codewords without any gap between them. This shows maximum throughput of the FEC-only interface.

Figure 1. 100G RX FEC-Only without Gap