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

ID 813652
Date 4/01/2024
Public
Document Table of Contents

6.3. GTS Transceivers Signals

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.

Clock Mode – Non-External clock mode.

tx_clkout [0] of the GTS PMA transceiver is connected to tx_coreclkin [0],[1],[2],[3].

rx_clkout [0] of the GTS PMA transceiver is connected to rx_coreclkin [0],[1],[2],[3].

Pll_reference of GTS PMA transceiver is configured to be 156.25. This also works with 312.5 MHz, however the GTS PMA transceiver must be configured again for the same.

The tx_clkout and rx_clkout is configured to be half-rate, which is 161.13 MHz.

There are two PLLs that convert the 161.13 MHz to 312.5 MHz.

The TX PLL reference clock input is tx_clkout[0], whereas the RX PLL reference clock input is rx_clkout[0].

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.