Bus request buffer circuit for interfacing between field maintenance processor and device specific adaptor.

摘要

A buffer circuit interfaces between a bus request conductor coupled to a processor and a bus request terminal of a first circuit that is capable of asserting control over a data bus coupled to the processor. The buffer circuit includes a flip-flop that stores a state indicative of whether the first circuit is monitoring or driving its bus request terminal. The buffer circuit also includes circuitry that reproduces the logic level of the bus request conductor on the bus request terminal of the first circuit if the flip-flop contents indicate monitoring by the first circuit and reproduces the logic level of the bus request terminal on the bus request conductor if the flip-flop contents indicate driving by the first circuit.