Agilex™ 5 ES Device Errata and User Guidelines

ID 825514
Date 11/07/2025
Public
Document Table of Contents

2.4.23. Reduced Reference Clock Frequency Options for Certain Output Frequencies in GTS System PLL Clocks IP

Description

Some reference clock frequencies listed in the drop-down list are not valid for certain GTS System PLL Clocks IP output frequencies. Selecting an invalid reference clock option will result in incorrect GTS System PLL Clocks IP output frequencies. The invalid reference clock frequency options are available in Quartus® Prime Pro Edition software version 25.3 and earlier. The invalid options will be removed in the future release of the Quartus® Prime Pro Edition software version.

Workaround

There is no workaround. Altera offers a TCL script to verify if the reference clock frequency selected in the GTS System PLL Clocks IP is valid. If the reference clock frequency is not valid, the script recommends the following alternatives:
  1. Provides a list of alternative reference clock frequencies while maintaining the same output frequency.
  2. Suggests two alternative GTS System PLL Clocks IP output frequencies while keeping the same reference clock frequency. You need to run the transceiver channels driven by the impacted System PLLs in custom cadence mode.
  3. In some cases, the script suggests retaining the same input and output clock frequencies. Install the patch for Quartus® Prime Pro Edition software version 25.3 to get legal dividers (automatically set by Quartus® Prime Pro Edition software) to maintain the same input and output frequencies.
Copy the tcl script (find_mcnt.tcl) to each of the generated IP folders of the GTS System PLL Clocks IP in your Quartus® Prime Pro Edition project.
  • For Linux operating system, change the directory to the IP folder and execute the command tclsh find_mcnt.tcl.
  • For Windows operating system, run the script from the Tcl Console within the Quartus® Prime Pro Edition Software GUI.

Implement one of the workarounds suggested in the TCL script. Install the patch for Quartus® Prime Pro Edition software version 25.3, regenerate the GTS System PLL Clocks IP and recompile your Quartus® Prime project.

Refer to the associated Knowledge Base entry to download the TCL script and patch.