Due to a problem in the Quartus® II software version 10.0 and later, when you open an existing ALTLVDS_RX megafunction in the MegaWizard Plug-In Manager, the previous setting for the After how many pulses does the data alignment circuitry restore the serial data latency back to 0? option may not be correctly restored. This setting corresponds to the data_align_rollover parameter in the megafunction variation file.
To ensure your variation file is created correctly, check this setting when re-opening an existing ALTLVDS_RX megafunction and correct the setting if it has not been correctly restored. Once the setting is corrected, the variation file is generated with the correct value for the data_align_rollover parameter.
To verify that your ALTLVDS_RX megafunction has the correct value for your design, examine your megafunction variation file for the following:
- For VHDL, examine the value for
data_align_rolloverin the Generic Map section of the variation file. - For Verilog HDL, examine the value for
data_align_rolloverin the defparam section of the variation file.
This problem is scheduled to be fixed in a future release of the Quartus II software.