The evolution of the FASTBUS general purpose master (GPM)

The numerous programmable FASTBUS masters of the LEP data acquisition systems are mainly based on the Motorola 68-K microprocessor family. The GPM technique is used to couple the 68-K data bus to FASTBUS much like memory mapped I/O. A small set of addresses is provided to select all varieties of the FASTBUS protocol. The technique is called general purpose because any operation in FASTBUS can be written like a program. The discussion covers the architecture, applications software support, embedded processors, and hardware.<>