The implementation of codesign applications generally requires the use of heterogeneous resources (e.g., processor cores, hardware accelerators) in one system. Interfacing hardware and software components together and providing communications between them are particularly error proned and time consuming tasks. Hence, on the basis of a generic architecture we propose an extended communication synthesis method that provides characterization of communications and their implementation scheme in the target architecture. This method takes place after partitioning and scheduling and can constitute the basis of a back end of a codesign framework leading to HW/SW integration.