GPIBDoc.tioga
Last Edited by: Gasbarro April 25, 1986 9:47:31 am PST
GPIB
CEDAR 6.0 — FOR INTERNAL XEROX USE ONLY
GPIB
Jim Gasbarro
© Copyright 1986 Xerox Corporation. All rights reserved.
Abstract: GPIB is an interface which provides a communication path from Cedar machines to devices which speak the IEEE-488 General Purpose Interface Bus (GPIB) protocol.
Created by: Gasbarro.pa, Gunther.pa
Maintained by: Jim <Gasbarro.pa>, Tim <Diebert.pa>
Keywords: GPIB, IEEE-488, Busmaster, DandeTiger, RPC
XEROX Xerox Corporation
Palo Alto Research Center
3333 Coyote Hill Road
Palo Alto, California 94304
For Internal Xerox Use Only
1. Organization
GPIB implements the IEEE-488 (GPIB) functions for a D-machine connected to a Busmaster Multibus adaptor. The implementation is comprised of 2 parts. The upper level PROCs conform to the procedural interface specified in GPIB.mesa; the lower level PROCs implement the board-specific calls. All future GPIB implementations for interfaces other than the National Instruments GPIB-796P board should conform to this organization.
The original code to drive the GPIB-796P board was transliterated from a 'C' implementation purchased from National Instruments. The following is paraphrased from the original National Instruments documentation:
These procedures support synchronous, non-interrupt I/O, for a single interface board which is always both the system controller and the controller in charge. All procedures return the subset of the standard GPIB status bit vector consisting of just the SRQI and BusEND status bits.
The result of the last call is also available in the global variable, statusWord. If it was an I/O operation the actual count transferred is available in the global variable, byteCount. Before any other call is made InitializeController[] must be called to initialize the GPIB interface. At level 2, prior to calling DataRead[] or DataWrite[] the appropriate devices, including the interface board, must be addressed by calling Cmd[] with the proper addressing codes.
2. Hardware
Currently to use the GPIB interface you need a DandeTiger with a Busmaster Multibus adapter connected. At some point in the future these facilities may be available on Daybreaks (6085).
3. RPC
In addition to the main GPIB interface and implementation, GPIB.df contains all that is necessary to use the GPIB interface from a remote machine via RPC. This code is not part of the public interface to the df so you will have to use the /a switch when you do the bringover. Then type GPIBServer on the machine with the real hardware interface and GPIBClient on the remote machine to start up the client (NOTE: you will have to modify GPIBClientImpl.mesa to point to the right target machine). You can then operate the GPIB bus remotely.
4. More Information
For more information about the National Instruments GPIB-796P controller contact National Instruments, 12109 Technology Boulevard, Austin TX 78727 (800)531-5066, or find the hardware manual that came with the board (it usually lives in the VLSI Test lab).