GTS Transceiver PHY User Guide: Agilex™ 5 FPGAs and SoCs

ID 817660
Date 10/17/2025
Public
Document Table of Contents

3.5.4. FEC Signals

Table 47.  FEC Signals
Signal Name Clocks Domain/Resets Direction Description
o_fec_status_rx_not_deskew 33 asynchronous output All RX lanes locked but the alignment markers were not unique or the skew was too large. Only applicable in multi-lane.
o_fec_status_rx_not_locked 33 asynchronous output RX lane not locked. Not locked to alignment and codeword markers or RS-FEC codewords (when not using markers). Only applicable in multi-lane.
o_fec_status_rx_not_align 33 asynchronous output Incoming signal fail, RX lanes not all locked, alignment markers not unique or skew too large. Only applicable in multi-lane.
o_fec_sf asynchronous output Signal fail, low means FEC is aligned.
Note: FEC alignment can be lost if:
  • The error rate exceeds the correction capability.
  • The FEC header is corrupted or missing.
  • The transmitter and receiver are configured for different FEC modes or parameters.
  • Clock synchronization is lost or signal quality is poor.
i_fec_snapshot asynchronous input Takes a snap of FEC status to CSR, uses Avalon® memory-mapped to read the content. Multi-lane FEC is not supported.
Note: When FEC alignment is lost, you should verify that the transmitter and receiver FEC settings match, ensure proper clock synchronization, check and improve physical connections and troubleshoot for sources of signal degradation.
33 This signal is only valid for RS-FEC.