50G Interlaken Intel® FPGA IP User Guide

ID 683217
Date 10/31/2022
Public
Document Table of Contents

8.1.6. Use ATX or CMU PLL

The USE_ATX parameter specifies whether the transceivers use the ATX PLL or the CMU PLL. If this parameter has the value of 0, the 50G Interlaken IP core transceivers are configured to use the CMU PLL. If this parameter has the value of 1, the 50G Interlaken IP core transceivers are configured to use the ATX PLL.

This parameter is not available in IP core variations that target an Intel® Arria® 10 device. These variations do not include a TX PLL. Instead, you must configure an external PLL and connect it to the IP core.

If the transceivers use the ATX PLL, more transceiver block logical channels are available for the eight Interlaken lanes. However, some lower pll_ref_clk frequencies are not available with the ATX PLL.

The default value of this parameter is 0, specifying that the IP core transceivers use the CMU PLL and have available the full range of pll_ref_clk frequencies documented for this input clock.