Why does the insertion loss range of the VSR_HIGH_LOSS and VSR_LOW_LOSS parameters in the F-Tile Architecture and PMA, and the FEC Direct PHY IP User Guide "3.12.2. FGT PMA Settings" change in the Quartus® Prime Pro Edition software version 24.2?

Description

VSR mode settings in the F-Tile Architecture and PMA and FEC Direct PHY IP User Guide “3.12.2 FGT PMA Settings” 

[version 24.1]

VSR mode is set when insertion loss < 10dB, RX auto adaptation is ON for >= 23 Gbps NRZ or any PAM4 rate:

• For Insertion Loss < 5 dB: 
  • set_instance_assignment -name HSSI_PARAMETER "vsr_mode=VSR_MODE_LOW_LOSS" - to <RX_SERIAL_PIN> -entity <TOP_LEVEL_NAME>
• For Insertion Loss > 5 dB but < 10 dB:
  • set_instance_assignment -name HSSI_PARAMETER "vsr_mode=VSR_MODE_HIGH_LOSS" - to <RX_SERIAL_PIN> -entity <TOP_LEVEL_NAME> 

Else VSR_MODE_DISABLE is set by default by the Quartus® Prime Pro Edition software for rates below < 23 Gbps, where VSR is not required.

[version 24.2 and onward]

VSR Mode for NRZ:

• Data Rate >= 23 Gbps and Insertion Loss <= 10 dB: 
  • set_instance_assignment -name HSSI_PARAMETER "vsr_mode=VSR_MODE_LOW_LOSS" - to <RX_SERIAL_PIN>  -entity <TOP_LEVEL_NAME> 
• Others: 
  • set_instance_assignment -name HSSI_PARAMETER "vsr_mode=VSR_MODE_DISABLE" -to <RX_SERIAL_PIN>  -entity <TOP_LEVEL_NAME>
     

Resolution

The change is not dependent on the Quartus® Prime Pro Edition software version. It is due to more validation data regarding VSR mode in NRZ and PAM4, showing a more accurate understanding of the insertion loss relationship with VSR mode.