AR# 12259: 5.1i NGDBuild LogiCORE PCI-X - "WARNING:NgdBuild:479 - The input pad net 'RST_N' driving one or more clock loads should only use a dedicated clock buffer..."
AR# 12259
5.1i NGDBuild LogiCORE PCI-X - "WARNING:NgdBuild:479 - The input pad net 'RST_N' driving one or more clock loads should only use a dedicated clock buffer..."
General Description: When I implement a PCI-X design (particularly one synthesized using Synplicity), NGDBuild issues the following warning:
"WARNING:NgdBuild:479 - The input pad net 'RST_N' driving one or more clock loads should only use a dedicated clock buffer. This could result in large clock skews on this net."
Solution
This warning is expected and can be safely ignored.
If the net in question is a clock net, then check to make sure the correct type of BUF is being used to drive the clock net.