Why are HSSI RX PMA settings for RX DFE Tap 1 parameter in the Agilex™ 5 FPGA GTS transceiver limited to a value < 6?

Description

Due to a problem in the Quartus® Prime Pro Edition Software version 24.1, you might see HSSI RX PMA settings for RX DFE Tap 1 parameter in the Agilex™ 5 GTS transceiver is limited to value < 6 when you try to manually configure this setting in the Quartus® Prime settings file (.qsf) or by using the Assignment Editor tool. 

As a result, you might not be able to use all the settings available in this DFE Tap 1 equalizer to optimize your GTS RX PMA link during RX manual tuning.

Resolution

To work around this problem, perform a direct register write to update the GTS RX PMA DFE Tap 1 register value only during user mode. The offset register address information for the GTS RX PMA DFE Tap 1 settings can be found in the Agilex™ 5 FPGA GTS Transceiver PHY User Guide, under the register map section GTS PMA/FEC Direct PHY IP Register Map.

The supported range of the DFE TAP 1 parameter is from 0 to 63.

This problem is fixed beginning with the Quartus® Prime Pro Edition software version 24.2.