Answers Database

M1 NGDBUILD: ERROR:basnu - logical net "signal" has multiple drivers.


Record #2678

Product Family:  Software

Product Line:  FPGA Implementation

Problem Title:
M1 NGDBUILD: ERROR:basnu - logical net "signal" has multiple drivers.


Problem Description:
Keywords: NGDBUILD, basnu, tristate, EDIF, XNF, Workview Office, Viewlogic

Urgency : Standard

General Description:
Running M1 translation gives these error when reading the EDIF netlist from
a Viewlogic design:

ERROR:basnu - logical net "signal" has multiple drivers.
ERROR:basnu - logical net "signal" has both active and tristate buffers.

The design had been processing properly with the XACTstep 6.0 XNF flow.


Solution 1:

The design may have a top-level symbol (root block).  Check for symbol that
is named the same as the top-level schematics. This symbol may have input or
output pins that are signals driven by IBUF or driving TBUF in schematics.

These cause confusion in ngdbuild because the EDIF netlist writer will look
for this symbol and take the information along with information from the
schematic sheets.

All XNF translation will not give problem because there is no root block
concept with WIR2XNF.  The information from top-level symbol will be removed
during XNF translation.

SOLUTION:
1. Remove the symbol from the project. If the design is in Workview Office,
   just move or delete 'design.1' file from the 'SYM' directory.

or

2. Modify the toplevel symbol pins so it refers to signals coming out of
   IPAD (input of IBUF or IFD) and signals going in to OPAD (output of OBUF,
   OBUFT or OFD).

After making the above corrections, check the design and regenerate the EDIF
netlist.



End of Record #2678