F-Tile CPRI PHY Intel® FPGA IP User Guide

ID 683284
Date 12/04/2023
Public

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4.2.2. Calculation for 64b/66b Datapath

If the 64b/66b datapath RSFEC is enabled, perform the following steps to configure the DL logic in F-tile before the RX latency calculation:
  1. Ensure the o_rx_blocklock signal is asserted.
  2. Read the RSFEC code word position value from rsfec_cw_pos_rx register, num field using the Datapath Avalon memory-mapped interface. For more information, refer to the F-Tile Ethernet Intel FPGA Hard IP Register Map.
  3. Program the RSFEC code word position value to FGT fgt_q_dl_ctrl_a_l<x> register, cfg_rx_lat_bit_for_async field using the PMA Avalon memory-mapped interface. The fgt_q_dl_ctrl_a_l<x> register is based on the placement of the FGT transceiver:
    1. FGT15, FGT11, FGT7, FGT3: fgt_q_dl_ctrl_a_l3
    2. FGT14, FGT10, FGT6, FGT2: fgt_q_dl_ctrl_a_l2
    3. FGT13, FGT9, FGT5, FGT1: fgt_q_dl_ctrl_a_l1
    4. FGT12, FGT8, FGT4, FGT0: fgt_q_dl_ctrl_a_l0
    For more information, refer to the F-Tile PMA/FEC Direct PHY Intel FPGA IP Register Map.
  4. Reset the deterministic measure logic for RX datapath by asserting the rx_dl_restart bit at register offset 0x8 using the reconfig_cpri interface.
  5. Release the reset for deterministic measure logic for RX datapath by clearing the rx_dl_restart bit at register offset 0x8 using the reconfig_cpri interface.