Low Latency 40G Ethernet Intel® FPGA IP User Guide: Agilex™ 5 FPGAs and SoCs

ID 813652
Date 11/25/2024
Public
Document Table of Contents

6.3. TX PCS Interface to User Logic

The Tx PCS interface signals are available only in PCS and PMA mode. The user interface for the PCS transmit direction is an XLGMII interface.
Table 16.  TX PCS XLGMII Signals
Signal Name Direction Width Description
clk_tx_mii Output 1 The Tx clock from the IP core and the Tx MII interface should be synchronous to clk_tx_mii. The frequency of this clock is 312.5 MHz. This is derived from the clk_ref_p/n of the SM PMA.
tx_mii_d Input 128 MII data input from Client to Tx PCS, synchronous to clk_tx_mii. Takes two data blocks per cycle.
tx_mii_c Input 16 MII control input from Client to PCS, synchronous to clk_tx_mii. Takes two control blocks per cycle.
tx_mii_am Input 1

Alignment marker from Client to PCS, synchronous to clk_tx_mii. The client must hold this signal asserted for 2 clk_tx_mii consecutive clock cycles, counting only the valid cycles, to drive the insertion of an alignment marker. A valid cycle is one in which tx_mii_valid has the value of 1.

While you hold the value of the tx_mii_am signal at 1, you must freeze the values of both tx_mii_d and tx_mii_c.

tx_mii_valid Input 1 Indicates that tx_mii_d is valid, synchronous to clk_tx_mii. Client must assert this signal a fixed number of clock cycles after the IP core raises tx_mii_ready, and must deassert this signal the same number of clock cycles after the IP core deasserts tx_mii_ready. The number must be in the range of 0 to 9 clock cycles. While you hold the value of this signal at 0, you must freeze the values of both tx_mii_d and tx_mii_c stable.
tx_mii_ready Output 1 Indicates the Tx PCS is ready to accept the new data, synchronous to clk_tx_mii.