problem description: When a design is synthesized with version 1999.1c of Leonardo Spectrum, the netlist gives an unexpanded block error in ngdbuild for the GND component.
The affected families are all Xilinx XC3000, XC3100, XC5200 and all xc4000 variants, Spartan and SpartanXL.
解决方案
This is a problem with the Leonardo tool generating an incorrect port name for the gnd component.
The exported netlist contains a Xilinx GND component who's port is named 'O'. The port name should be 'G'.
This problem has been fixed since ExemplarSpectrum 1999.1d.