The design of a FASTBUS module providing an intelligent interface to the American National Standards Institute standard small computer system interface bus (SCSI) was investigated in Phase I. The module is to provide a high speed communication link between a FASTBUS system and a variety of computers and workstations. It will also allow any SCSI peripheral device, such as a disk or tape drive, to be directly connected to a FASTBUS system. The result of Phase I was the design of a module providing either four independent eight-bit wide SCSI ports, or a single thirty two-bit wide port implementing the SCSI wide data transfer option. In the latter case, a transfer rate of twenty megabytes per second will be possible, using the SCSI synchronous protocol. The interface will function as either an SCSI bus initiator or target. As an initiator, it will permit any FASTBUSmaster to access any SCSI peripheral, or another processor responding as an SCSI processor type device on the SCSI bus. When acting as a target, the module will respond as a processor type device itself, and permit another SCSI initiator to exchange data with FASTBUS slaves or memory. To achieve this functionality, the module will have the capability of acting as a FAS1 BUS master as well as a slave. Phase I resulted in a proposed design of the software interface to the modules as well as a hardware proposal. The latter uses individual microcontrollers to control several SCSI protocol chips, and a microprocessor to provide overall supervision and communication with the FASTBUS segment via a FASTBUS protocol chipset. During Phase II, the hardware design will be breadboarded, and the software written for each of the microprocessor systems. The objective will be a fully functional FASTBUS module, which will be tested in several actual FASTBUS environments.Anticipated Results/Potential commercial Applications as described by the awardee:The proposed FASTBUS module will provide a high speed communication link between FASTBUS and a variety of computers and workstations. Many of these provide the SCSI port at no additional cost, and in some cases SCSI is theonly possible communication medium. In addition, the proposed interface will allow any of a wide range of SCSI peripheral devices to be used with FASTBUS with no additionalhardware. A connection between FASTBUS and computer automated measurement and control (CAMAC) is possible using recently developed SCSI CAMAC crate controllers.
