GTS Dynamic Reconfiguration Controller IP User Guide: Agilex™ 5 FPGAs and SoCs

ID 849710
Date 8/11/2025
Public
Document Table of Contents

7. Sharing Clocking and Applying SDC Constraints

Follow these requirements to ensure clocking consistency across IPs in a DR Group:
  1. System PLL Clocking:
    • All IP variants on the same channels must use the same System PLL clock.
    • Ensure that all instantiated IP variants support the System PLL frequency.
    • Do not switch between System PLL and PMA clocking for DR.
  2. Avalon® memory-mapped interface Clock:
    • Use the same AVMM clock for all IP variants in the DR Group.
    • Match the AVMM clock with the DR Controller's i_csr_clk and all i_dr_lavmm_clk_ch<N> inputs.
  3. TX/RX Datapath Clock:
    • Source the TX/RX datapath clock for each IP on the same channel from either the System PLL or the System PLL/2, depending on the datapath width settings of the IP.
    • For Direct PHY, set tx_clkout source to Sys PLL Clock, div by 2. Drive tx_coreclkin and rx_coreclkin for all lanes with tx_clkout.
    • For Dual-simplex, use rx_clkout for rx_coreclkin on the RX side, as long as all profiles in the same channel follow this clocking.
    • For Ethernet, drive i_clk_tx and i_clk_rx from o_clk_pll.
    • For CPRI, set tx_user1_clk_dynamic_mux to PLL_C0.
  4. Do not reconfigure a Dual-Simplex IP to a Duplex IP or vice-versa.
  5. Deterministic Latency Sampling Clock:
    • Source the sampling clock from the same signal for IP variants that use DL, such as CPRI and Ethernet+PTP, in the same channel.
    • If different clock frequencies are needed, handle switching by reconfiguring a PLL or using a mux.
  6. Add the following to the project's SDC file to properly analyze timing:

    Group clocks from mutually exclusive IP variants into clock groups. For example:

    • set_clock_groups -physically_exclusive -group [get_clocks dr_top_inst.ip_variant_1_inst.*] 
      -group [get_clocks dr_top_inst.ip_variant_2_inst.*]