AR# 9306


3.1i ECS: ERROR:NgdBuild:455 - logical net 'xxx' has multiple drivers


Keywords: Project Navigator, NGDBUILD, 467, macro

Urgency: Standard

General Description: The following Ngdbuild errors:

ERROR:NgdBuild:467 - output pad net 'xxxx' has an illegal buffer
ERROR:NgdBuild:455 - logical net 'xxx' has multiple drivers

can be caused by the following:

1- Using IO macros in an ECS schematic
2- Naming two driving nets the same name
3- Instantiating special purpose buffers (LVDS, LVPECL) and
synthesizing with FPGA Express



If the schematic contains IO macros there are two solutions:

1- Deselect the "Insert I/O" option during synthesis.
2- Replace the macros with primitives.

A complete description of each component can be found in
the Xilinx Libraries Guide - (


To determine if two nets with the same name are
driving use the DRC -> Query in ECS. Once the duplicate
name is found, change one of the net names.
AR# 9306
Date 01/16/2003
Status Archive
Type General Article
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