  This paper provides an overview of the CODA framework for modelling and
refinement of component-based embedded systems. CODA is an extension of Event-B
and UML-B and is supported by a plug-in for the Rodin toolset. CODA augments
Event-B with constructs for component-based modelling including components,
communications ports, port connectors, timed communications and timing
triggers. Component behaviour is specified through a combination of UML-B state
machines and Event-B. CODA communications and timing are given an Event-B
semantics through translation rules. Refinement is based on Event-B refinement
and allows layered construction of CODA models in a consistent way.
