Efficient instrument design using IEEE 488.2

IEEE 488.2 defines standard formats, protocols, and common commands for IEEE 488 programmable instrumentation. Conventional software techniques can be used to write a parser that implements the formats and common commands. Such a parser requires a simple data stream interface, where data are simply gotten (commands) or placed (responses). The author describes a software driver for an IEEE 488 interface. This driver provides a simple data stream interface to the parser while conforming to the protocol requirements of IEEE 488.2. The crux of this implementation is the isolation of the message exchange control protocol, which is implemented with a simple state machine, from the parser. The protocol requirements of IEEE 488.2 have been converted to a state machine where each transition is the result of an external signal. In this process some anomalies in IEEE 488.2 have been identified and corrected.<
>