Error: Implementation of M4K memory block WYSIWYG primitive "<>" of altsyncram megafunction does not work with current target device family. Please refer to the Cyclone® II FPGA Family Errata Sheet for more information on this feature.

This error message occurs beginning in the Quartus^® II software version 5.1 when your memory configuration is not compatible with the Cyclone II device family due to the issues described in the Cyclone II FPGA Family Errata Sheet (PDF). The message indicates that the Quartus II Fitter could not be automatically convert the memory block into a compatible configuration.

If your device is affected by the issues described in the errata sheet and you receive this error message, you can either change your design to avoid using the unsupported memory configuration or target fixed revision silicon devices. Refer to the errata sheet for details on how to target fixed revision silicon devices.