Why does an ALT_INBUF_DIFF primitive instantiation result in a Quartus II error?

Description

The ALT_INBUF_DIFF primitive is supported only for Stratix® III and Cyclone® III devices. If you compile a design that instantiates this primitive and targets another device such as a Stratix II or Stratix II GX device, the Quartus® II software generates an error.

To fix this problem, do not use ALT_INBUF_DIFF primitive in your HDL code if your design targets an unsupported device.

For more information about using primitives, refer to the Designing With Low-Level Primitives User Guide (PDF).