Quartus® Prime Pro Edition User Guide: Design Optimization

ID 683641
Date 4/01/2024
Public

A newer version of this document is available. Customers should click here to go to the newest version.

Document Table of Contents

5.5.9.14.5. Global Routing Resources

Global routing resources are designed to distribute high fan-out, low-skew signals (such as clocks) without consuming regular routing resources. Depending on the device, these resources can span the entire chip or a smaller portion, such as a quadrant. The Quartus® Prime software attempts to assign signals to global routing resources automatically, but you might be able to make more suitable assignments manually.

For details about the number and types of global routing resources available, refer to the relevant device handbook.

Check the global signal utilization in your design to ensure that the appropriate signals have been placed on the global routing resources. In the Compilation Report, open the Fitter report and click Resource Section. Analyze the Global & Other Fast Signals and Non-Global High Fan-out Signals reports to determine whether any changes are required.

You might be able to reduce skew for high fan-out signals by placing them on global routing resources. Conversely, you can reduce the insertion delay of low fan-out signals by removing them from global routing resources. Doing so can improve clock enable timing and control signal recovery/removal timing, but increases clock skew. Use the Global Signal setting in the Assignment Editor to control global routing resources.