Why is receiver termination reported as “Off” for the PCI Express* differential data pair in the Quartus® Prime Pro Edition software version 25.1.1 for design targeting Agilex™ 7 FPGA F-Tiles Devices?

Description

Due to a problem in Quartus® Prime Pro Edition Software version 25.1.1 and earlier, the on-chip termination setting for the PCIe* differential data pair incorrectly reported in Fitter Report. However, the actual default receiver termination was set to 100 Ohms.

Resolution

This problem is fixed beginning with the Quartus® Prime Pro Edition software version 25.3.1.

The default receiver termination is updated to 85 Ohms. The existing 100 Ohms continues to be available as an option after the fix. Both 85 Ohms and 100 Ohms receiver termination settings have been validated, and test results confirm compliance with PCIe specifications. The receiver on-chip termination parameter will be available in the IP Parameter Editor for F-Tile Avalon Streaming IP for PCI Express after the fix. The 100 ohms setting in the existing design will be retained when migrating to the new Quartus Prime Pro Edition software version, unless the user explicitly changes it in the IP Parameter Editor. Existing designs can continue using the 100 ohms setting without problem, while the 85 ohms setting is recommended for new designs.

In the Quartus® Prime Pro software Compilation Report, the receiver termination setting can be verified under:

Synthesis > Analysis & Elaboration Stage > Parameter Settings by Entity Instance > Parameter Settings for User Entity ftileb_ag_v0 Instance: pcie_ed_auto_tiles.

• Parameter Name: *rx_onchip_termination
• Value:
• *rx_onchip_termination_r_1 (representing 85 ohms)
• *rx_onchip_termination_r_2 (representing 100 ohms)