According to a blog post introducing the specification, AMBA C2C is being developed with the AMBA ecosystem to provide a unified, scalable way to connect AMBA protocols across chiplets. It extends the earlier AMBA CHI C2C work to cover both CHI and the widely used AXI protocol. The post argues that while CHI C2C suits fully coherent, advanced heterogeneous systems, many chiplet use cases such as memory expansion and accelerator attach need a simpler approach.
Central to AMBA C2C is protocol subsetting. Defined subsets allow the feature set and implementation complexity to scale: simpler subsets target AXI-based IO and non-coherent traffic, while advanced subsets support coherent, heterogeneous systems. The specification builds on the property negotiation mechanism introduced with CHI C2C, which is intended to let implementations with different capabilities interoperate across chiplet types, vendors, and generations, including backwards and forwards compatibility.
The architecture separates protocol and packetization from the underlying transport, a layered model the post says is already used by UCIe and UALink. AMBA defines the protocol and packetization, while transports such as UCIe handle die-to-die connectivity. This separation is especially relevant for AXI, which defines interface behavior rather than a native packet format; AMBA C2C must specify which AXI semantics are carried and how they are packetized, and that definition must evolve alongside AXI.
The post says the specification is being developed with industry partners and will be freely available, royalty-free, and architecture-neutral. It frames AMBA C2C as the next step in AMBA's chip-to-chip work, providing a common foundation from simple AXI-based designs to CHI-based coherent systems. As with any single-source announcement, these claims reflect the developer's stated plans rather than an independent assessment.