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AR# 17826

2003x LeonardoSpectrum - When instantiating a IBUFGDS_LVPECL_25 LeonardoSpectrum adds an extra IBUFs on the input

Description

Keywords: Leonardo, Spectrum, EDIF, differential, ibufgds

Urgency: Standard

General Description:
When instantiating a IBUFGDS_LVPECL_25 using Synplify, NGDBUILD errors with:

ERROR:NgdBuild:455 - logical net 'ck133_n_c' has multiple drivers. The possible
drivers causing this are pin O on block ck133_n_ibuf with type IBUF, pin PAD
on block ck133_n_c with type PAD
WARNING:NgdBuild:463 - input pad net 'ck133_n_c' has an illegal input buffer
ERROR:NgdBuild:466 - input pad net 'ck133_n_c' has illegal connection. Possible
pins causing this are pin O on block ck133_n_ibuf with type IBUF
ERROR:NgdBuild:455 - logical net 'ck133_c' has multiple drivers. The possible
drivers causing this are pin O on block ck133_ibuf with type IBUF, pin PAD on
block ck133_c with type PAD
WARNING:NgdBuild:463 - input pad net 'ck133_c' has an illegal input buffer
ERROR:NgdBuild:466 - input pad net 'ck133_c' has illegal connection. Possible
pins causing this are pin O on block ck133_ibuf with type IBUF

Solution

LeonardoSpectrum is adding extra IBUFs onto the primitive, thus you have an IBUF driving an IBUFGDS. This is an illegal connection. By disabling IO Buf insertion and manually instantiating input and output buffers, you can avoid this problem.
AR# 17826
Date Created 08/19/2003
Last Updated 04/25/2007
Status Archive
Type General Article