AR# 5208: MAP: "ERROR:xvkma:120 - LUT* symbol has an equation that has no connected signal" with Synplify 5.0.x
MAP: "ERROR:xvkma:120 - LUT* symbol has an equation that has no connected signal" with Synplify 5.0.x
Keywords: Synplify, Map, xvkma
General Description: When generating implementation netlists for Virtex, selecting "Result Format: XNF" within Synplify 5.0.x generates following Map error:
ERROR:xvkma:120 - LUT2 symbol "controller.write_sdram_sm.un73_axb_2" (output signal=controller.write_sdram_sm.un73_axb_2) has an equation that uses an input pin that has no connected signal. Make sure that all the pins used in the equation for this LUT have signals that are not trimmed (see trim report for details on which signals were trimmed). The original signals connected to the LUT are: VCC buffer_max_size controller.write_sdram_sm.un73_axb_2.
This was common in versions of Synplify prior to 5.1.2. If you are using a more recent version, this error is due to bad connections in the netlist such as nets that are not driven or hanging. Please contact Synplicity support for assistance if the below suggestion does not solve your problem.
For versions prior to 5.1.2, select "Result Format: EDIF" when generating implementation netlists for Virtex. The resultant EDIF now contains cell declarations for VCC and GND that drive the dangling nets. Target -> Set Device Options -> Result Format -> EDIF
This is fixed in Synplify 5.1.2 and later. Synplicity has removed the option of targetting to XNF for Virtex in this version.