GTS Transceiver PHY User Guide: Agilex™ 5 FPGAs and SoCs

ID 817660
Date 10/17/2025
Public
Document Table of Contents

3.4.1. Clock Generation and Constraints for Multiple Profiles Design

Clocks should be created for each profile, with up to four clocks per profile (TX, RX, CLKOUT1, and CLKOUT2). The netlist from the base profile should be used as the source for each clock. Additionally, you must specify physically exclusive clock groups across profile clocks in the constraints file.

For timing constraints, generate separate clocks for each profile and run the SDC analysis independently per profile. Identify the maximum frequency among all profiles and constrain the design accordingly. From the Quartus® Prime 25.3 release onward, each individual profile has its own separate SDC file. The SDC for a profile is no longer determined by taking the maximum values across all profiles. Instead, each profile’s SDC is tailored to its specific requirements. For example, based on the selected device profile, use the frequency specified for that profile, such as 17.1 Gbps or 28.1 Gbps, along with its corresponding CLKOUT frequency and divisor value when configuring the design.

The Multirate Ethernet PHY, CPRI, and SDI IPs utilize the GTS PMA/FEC Direct PHY IP for multirate support. However, not all IPs operate at the maximum frequency, as some work with lower line rates instead of the highest CLKOUT frequency.