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

6.10. Clocks

Table 23.  Clock Signals
Signal Name Direction Width Nominal Frequency (MHz) Description
clk_txmac Output 1 312.5 Clock for TX section. This is the derived clock from the ref_clk_p/n, and the frequency of this is 312.5 MHz and this signal is used in MAC, PCS, and PMA variant.
clk_rxmac Output 1 312.5 Clock for RX section. This is the recovered clock from the Rx serial data, and the frequency of this is 312.5 MHz and this signal is used in MAC, PCS, and PMA variant.
clk_ref_p Input 1 156.25 This clocks the CDR in the receive direction of the transceivers – differential clk.
i_system_pll_clk Input 1 156.25 Syspllclk from sys_clk_IP.
clk_status Input 1 100 to 125 Avalon® memory-mapped interface clock.
reconfig_clk Input 1 100 to 125 Transceiver reconfiguration clock.
i_pma_cu_clk Input 1 250

Input from GTS Reset Sequencer Intel® FPGA IP to Low Latency 40G Ethernet Intel® FPGA IP.

It is one per QUAD feeding the FLUX uC in the transceiver.

clk_tx_mii Output 1 312.5 Clock for TX section. This is the derived clock from the ref_clk_p/n and this signal is used in PCS and PMA variant.
clk_rx_mii Output 1 312.5 Clock for RX section. This is the recovered clock from the Rx serial data, and this signal is used in PCS and PMA variant.
clk_rx_recover Output   312.5 Rx Recover clock. Available only if you turn on Enable SyncE in the parameter editor.
cdr_divclk Output   Setting clk_ref as 156.25 MHz, 312.5 MHz, or 322.265625 MHz directly sets cdr_divclk to the same frequencies.

Dedicated Rx Recover divided clock output from PMA over the Local Reference Clock pins or dedicated CDR clock output pins.

Available only if you turn on Enable SyncE and enable_cdr_clkout in the parameter editor. The nominal frequency of cdr_divclk is the input PMA ref clockenb (clk_ref_p/n) divided by 1.