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  3. AR# 11222: 5.1i XST - "ERROR:NgdBuild:466 - input pad net 'ibuf_name' has illegal connection" (LVCMOS)

AR# 11222

5.1i XST - "ERROR:NgdBuild:466 - input pad net 'ibuf_name' has illegal connection" (LVCMOS)

Description

Keywords: LVCMOS2, LVCMOS25, Virtex, XST, instantiate, primitives

Urgency: Standard

General Description:
When I instantiate LVCMOS2-type buffers, XST issues some of the following warnings and errors:

"ERROR:NgdBuild:455 - logical net 'ibuf_name' has multiple drivers"
"WARNING:NgdBuild:463 - input pad net 'ibuf_name' has an illegal input buffer"
"ERROR:NgdBuild:466 - input pad net 'ibuf_name' has illegal connection"
"ERROR:NgdBuild:467 - output pad net 'obuf_name' has an illegal buffer"

Solution

When NGDBuild encounters a LVCMOS2-type buffer, it converts it to a LVCMOS25-type buffer. To avoid these warnings and errors, change the component in HDL from an LVCMOS2 to an LVCMOS25.
AR# 11222
Date 10/20/2005
Status Archive
Type General Article