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

6.5. GTS Transceivers Signals

The GTS Transceiver interface is accessible in both MAC, PCS, and PMA and PCS and PMA modes. The GTS Transceiver PHY IP uses four GTS PMA transceivers for the Low Latency 40G Ethernet Intel® FPGA IP. For more information, refer to the GTS Transceiver PHY User Guide .

The transceivers require a PLL ref clk as an input. The GTS PMA transceiver is configured for a specific setting in order for the successful integration of the existing Low Latency 40G Ethernet MAC and PCS with the GTS PMA transceiver.

Pll_reference clock of GTS PMA transceiver is configured to be 156.25 MHz.

For SYNC-E, the recovered clock that is rx_clkout[1] from GTS PMA transceiver is used. This is of frequency 312.5 MHz.

Table 18.  GTS Transceiver Signals

Signal

Direction

Width

Description

tx_serial Output 4 TX transceiver data. Each tx_serial bit becomes two physical pins that form a differential pair.
rx_serial Input 4 RX transceiver data. Each rx_serial bit becomes two physical pins that form a differential pair.
clk_ref_p Input 1 The PLL reference clock used by TX and RX. Input to the clock data recovery (CDR) circuitry in the RX PMA.
cdr_divclk Output 1 Dedicated RX recover divided clock output from PMA over the local reference clocks pins or dedicated CDR clock output pins. This clock is available only if you turn on “Enable SyncE” and enable cdr clkout in the IP parameter editor. The normal frequency of cdr_divclk is the input PMA ref clockenb (clk_ref_p/n) divided by 1.

The cdr_divclk uses the clk_ref pin for routing. When cdr_divclk is enabled, the number of available ref clocks is reduced to one except in Agilex™ 5 devices.