VME bus interfacing: A case study

VME is a new high performance standard bus for multimicoprocessor systems. Its characteristics originate in the 68000 microprocessor's interface signals. Processors with other interface characteristics can, however, also be used in VME systems. The case study of the interfacing of a 6809-based subsystem to the VME bus is presented. A mixture of hardware and software has been used to implement at low cost the matching functions. The 6809-based subsystem can perform all VME-related functions: bus requester in multiprocessor environments, bus master, interrupt handler, bus slave and interrupter. The last two functions are performed by a dual-port memory included in the subsystem, which is designed to be used as the main processor in small VME systems or as the intelligent peripheral controller in larger VME systems.