Description
Although the Quartus® II software version 2.0 correctly limits APEX™ II device PLL input frequencies to 420 MHz, the software incorrectly places this same restriction on high-speed differential (LVDS, LVPECL and HyperTransport™ technology) input clocks. APEX II devices support LVDS input clocks up to 500 MHz, as stated in the solution, What is the maximum high-speed differential (LVDS, LVPECL, and HyperTransport technology) input clock frequency that APEX II devices support?
This problem was fixed in the Quartus II software version 2.1.