Emerson MVME147 User Manual

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GENERAL INFORMATION
Introduction
The MVME147 MPU VMEmodule contains a port to the Small Computer
Systems Interface (SCSI) bus. The hardware interface is the WD33C93 SCSI
interface controller.
To relieve you of having to follow SCSI bus protocol, the SCSI firmware allows
you to pass commands to the bus through high level command packets.
Standard command packets are furnished, as well as custom SCSI sequence
packets that you may easily modify to fit particular applications. With this
method, the firmware interface can greatly speed up your software
development cycle.
The SCSI firmware resides in two 128K x 8 EPROMs and is co-resident with
MVME147Bug, the debug monitor for the MVME147 MPU VMEmodule.
Features
The SCSI firmware offers the following features:
Custom SCSI sequence packets that allow creation of customized
functions
TARGET role
Multitasking -- up to 64 concurrent peripheral devices
High level support of SCSI devices
Interrupt mode allows real-time applications
Polled mode -- non-interrupt operation
DMA with memory/scatter/gather
Multiple-user interface allows concurrent operation through independent
drivers
Six entry points
Thirty-one "canned" or standard function packets
Modes of Operation
When using the SCSI firmware, you have a choice of two modes of operation:
Interrupt mode and polled mode.