General Description : Leonardo produces EDIF file with EQN attribute to define LUTS. This was fine with the 4K devices. But with Virtex EQN attribute is redundant since we have INIT attribute to define the LUTS. But when the EQN attribute is greater than 500 characters Ngdbuild throws out an error.
Solution
In the case of Virtex, one can stop the generation of EQN in the EDIF net list produced by Leonardo by adding the following options in his script and modifying his write command.
# Turn off eqn property in EDIF file set edif_function_property "" # Turn on INIT property in EDIF file set xi_write_init_on_luts TRUE # Process database set rename_rule XILINX attach_equations . . . write -format edif D:/fdesign/exemplar/nofred/fred.edf
# To reset edif writer to use EQN property set edif_function_property "EQN"