GTS Transceiver PHY User Guide: Agilex™ 3 FPGAs and SoCs

ID 848344
Date 8/04/2025
Public
Document Table of Contents

3.13.1. Configuring the RX Adaptation Mode and PMA Manual Tuning

The RX adaptation mode is set by default when you configure your RX PMA in the GTS PMA/FEC direct PHY IP, based on the protocol mode and data rate you select. However, you can optionally change the RX adaptation mode from auto to manual and vice versa.

This section explains how you can use the .qsf assignment settings and the syntax to change the adaptation mode for your PMA links; only when required. In all cases, the default RX adaptation mode is the best recommended setting you can use for the protocol and data rate you select in the IP GUI. When you change the adaptation mode from RX auto adaptation mode to RX manual adaptation mode, you must manually configure the RX equalizer settings as explained in the later sections.

Auto Adaptation Mode: 26
If you want to change the RX manual adaptation mode configured in the GTS PMA/FEC Direct PHY IP to RX auto adaptation mode for a given PMA lane, you can use the following .qsf settings shown below:
set_instance_assignment -name HSSI_PARAMETER "flux_mode=FLUX_MODE_FLUX_MODE_SNIFFER" -to <RX_SERIAL_PIN>  -entity <TOP_LEVEL_NAME>
set_instance_assignment -name HSSI_PARAMETER "rx_adaptation_mode=RX_ADAPTATION_MODE_FLUX_ADAPTATION" -to <RX_SERIAL_PIN>  -entity <TOP_LEVEL_NAME>
In addition, if you are changing the RX adaptation mode to auto adaptation mode, you must configure the RX EQ settings to a value of 0 by using the following .qsf settings shown below:
set_instance_assignment -name HSSI_PARAMETER "rx_eq_vga_gain=0" -to <RX_SERIAL_PIN> -entity <TOP_LEVEL_NAME>
set_instance_assignment -name HSSI_PARAMETER "rx_eq_dfe_tap_1=0" -to <RX_SERIAL_PIN> -entity <TOP_LEVEL_NAME>
set_instance_assignment -name HSSI_PARAMETER "rx_eq_hf_boost=0" -to <RX_SERIAL_PIN> -entity <TOP_LEVEL_NAME>
Note: If you instantiate bonded-lane configuration in the GTS PMA/FEC Direct PHY IP and you want to change the RX adaptation mode from RX manual adaptation mode to RX auto adaptation mode, you must provide the .qsf setting for every PMA lane instantiated within the same GTS PMA/FEC Direct PHY IP, as this affects the Soft Reset Controller that is used to set the reset sequence of the bonded lanes.

Manual Adaptation Mode: 26

If you want to change the RX auto adaptation mode for the PMA lane configured in the GTS PMA/FEC Direct PHY IP to RX manual adaptation mode follow the .qsf settings shown below:
set_instance_assignment -name HSSI_PARAMETER "flux_mode=FLUX_MODE_FLUX_MODE_BYPASS" -to <RX_SERIAL_PIN> -entity <TOP_LEVEL_NAME>
set_instance_assignment -name HSSI_PARAMETER "rx_adaptation_mode=RX_ADAPTATION_MODE_MANUAL_ADAPTATION" -to <RX_SERIAL_PIN> -entity <TOP_LEVEL_NAME>

RX Manual Tuning:

If you configure the RX link to manual tuning mode (RX adaptation mode is set to manual mode in the IP GUI), you must provide the RX PMA analog settings. You can use the GTS Transceiver Toolkit Parameter Settings to tune the link during manual adaptation mode to find the optimal setting for the RX analog parameters. You can control the VGA gain, High frequency boost, and DFE Tap 1 PMA settings by selecting the value in the Analog Parameters tab or by using the following .qsf settings shown below:

  • VGA gain:
    set_instance_assignment -name HSSI_PARAMETER "rx_eq_vga_gain=<parameter_value>" -to <RX_SERIAL_PIN> -entity <TOP_LEVEL_NAME>
    
    Valid parameter values (decimal) are 0-63.
  • High frequency boost:
    set_instance_assignment -name HSSI_PARAMETER "rx_eq_hf_boost=<parameter_value>" -to <RX_SERIAL_PIN> -entity <TOP_LEVEL_NAME>
    Valid parameter values (decimal) are 0-63.
  • DFE Tap 1:
    set_instance_assignment -name HSSI_PARAMETER "rx_eq_dfe_tap_1=<parameter_value>" -to <RX_SERIAL_PIN> -entity <TOP_LEVEL_NAME>
    
    Valid parameter values (decimal) are 0-63.
    Note: If you are using the RX auto adaptation mode, do not configure the VGA gain, High frequency boost, and DFE Tap 1 PMA settings in the .qsf file, as it results in a compilation error.
26 You must program the soft CSR registers 0x10008[10] and 0x10008[17] for the PMA lane that you are changing the adaptation mode for from either auto adaption to manual adaptation or vice versa; to inform the Soft Reset Controller to correctly monitor either the CDR LTD status or auto adaptation ready signal status. This step is crucial to ensure that the correct reset sequence is used when the adaptation mode changes for the PMA lane. For more information, refer to: