描述

General Description: 

When I attempt to implement the PCI or PCI-X cores, NGDBuild reports the following warnings on several nets: 

For PCI: 

"INFO:NgdBuild:757- The constraint for NET 'PCI_CORE/RST_I' is being attached to the equivalent NET 'RST_N'." 

"INFO:NgdBuild:757- The constraint for NET 'PCI_CORE/AD_IO<31>' is being attached to the equivalent NET 'AD<31>'." 

For PCI-X: 

"INFO:NgdBuild:757 - The constraint for NET 'XPCI_WRAP/CLK_I' is being attached to the equivalent NET 'PCLK'." 

"INFO:NgdBuild:757 - The constraint for NET 'XPCI_WRAP/RST_I' is being attached to the equivalent NET 'RST_N'."

解决方案

These warnings may be safely ignored. The UCF file constrains signals in the wrapper file instead of at the top level of the design. The wrapper file, XPCI_WRAP, is one level down in the hierarchy; therefore, the UCF constraint constrains signals using the hierarchy path. NGDBUILD recognizes these signals constrained in the UCF are equivalent to signals named in the top-level file ports. NGDBUILD applies the constraint to the signals at the top level, which triggers this information message.