In Socrates the System Specification Generator supports NIC-400 and the like but not AHB Bus Matrix. Is the NIC-400 preferrable now? It does everything AHB Bus Matrix can do and more. What are the relative merits of using one over the other?
There are AHB BusMatrix components in the SIE-200 (AHB5) and CMSDK (AHB-lite) elements of the Socrates IP Catalog.
NIC-400 would not be preferable in all AHB based design as NIC-400 is AXI based, so any path through it would cross two unnecessary protocol conversions.
So choose the interconnect protocol based on what the majority of your connected components use, or based on the protocol your most latency critical components use. If there is no clear favourite, choose NIC-400 as it includes protocol conversion bridges to and from AHB-lite, whereas an AHB BusMatrix would need to have standalone AXI bridges added externally (which can be generated using NIC-400).