Why does Quartus II software targeting Arria GX devices gives compilation errors when I select any pre-tap or second post-tap Preemphasis values in ALT2GXB file generated by PCIe IP Megawizard?

ALT2GXB Megawizard™ file generated through PCIe IP Megawizard has a bug that allows you to select different values for the Preemphasis Pre-tap, fist post-tap and second post tap that should not be available for Arria® GX devices.

The reason for these additional/illegal pre-emphasis values is related to the PCIe®  IP Megawizard bug, which selects Stratix® II GX device within ALT2GXB Megawizard, instead of Arria GX devices.  To correct the issue,

*  Open up the ALT2GXB Megawizard file
*  On the “General” tab, “Currently Selected Device Family” will erroneously show Startix II GX device, instead of Arria GX device, even though your top level design file had Arria GX device selection
*  Uncheck the box “Match Project/default”
*  Select Arria GX device from the “Currently Selected Device Family” dropdown menu

With the correct selected device, you should be able to see only the legal Arria GX pre-emphasis values on the “TX Analog” tab.  These legal Pre-emphasis values are 0 to 5 for first post-tap.  Pre-tap and second post-tap will be grayed out, as they are not available in Arria GX devices.