Description
Due to a problem in the Quartus® II software version 12.1 and later, you may see fitter problems placing the ATX PLL when migrating from earlier versions of the Quartus II software.
Resolution
To work around this problem, add the Quartus II Settings File (.qsf) assignment for all related ATX_PLLs
set_instance_assignment -name XCVR_TX_PLL_RECONFIG_GROUP 1 -to **atx_pll.tx_pll