Frequently Asked Questions comp.arch.bus.vmebus
This list is maintained by: Robert Boys San Jose, California formerly of Guelph, Ontario, CANADA
- r.boys@genie.geis.com or
January 05, 1996 Version # 9
The information contained in this FAQ is believed to be correct and up to date. Every effort has been made to ensure accuracy. The maintainer cannot be responsible for errors and omissions. This article is copyright (c) 1996 and all rights are reserved. This article may be reprinted provided it is intact, proper credit is given and no cost is levied. Contact the author for permissions.
What's New! new parts are indicated with a ]
- The VMEbus - Introduction
- The VMEbus - Description
- DIN Connector Assignments
- VME64 - a new standard
- The VXIbus - Introduction
- The VXIbus - Description
- DIN Connector Assignments
- VMEbus Systems Magazine
- VXI Journal
- Real Time Engineering
- Micrology pbt, Inc.
- VITA - VMEbus International Trade Association
- Computer Design
- Test & Measurement World
- The Manufacturers
- Unadvertised ftp and WWW Sites
- Newbridge Microsystems
- Battery Clocks - MK48TO2B-xx
- Where does the name "VME" come from?
| Motorola Newbridge |
EKF Elektronik |
| Heurikon VITA |
Micrology pbt |
| DY 4 RadiSys |
Schroff, Inc |
| VMIC - VME Microsystems International |
Corp. |
| Radstone Technology PLC (UK) |
Themis Computer |
| Titan Electronics (San Diego) your firm name here (email me) |
et al |
The latest version of this FAQ is archived at:
http://www.ee.ualberta.ca/archive/vmefaq.html
or
http://www.hitex.com/automation/FAQ/vmefaq (California)
http://www.ba-karlsruhe.de/automation/FAQ/vmefaq (Germany)
ftp://nyquist.ee.ualberta.ca/pub/motorola/general/vmefaq
The working copy is on my Homepage - http://www.sentex.net/~rboys
You can retrieve the entire HTML FAQ with the .gif files by pointing
your browser at the above sites and look for vmefaq.zip
The VMEbus standard originated with the Motorola VERSAbus in 1979 which was designed using the then new MC68000 microprocessor. The VMEbus signals are patterned after the M68000 bus signals and timing. VMEbus boards now contain processors such as DEC Alpha, MIPS, i960, various DSP chips, AM29000 (RISC chip), PowerPC and 80486 in addition to the Motorola 680x0 line. Many peripheral boards exist including VGA, telecommunication, analyzers, data acquisition, video processors and memory (1 gigabyte!). The VMEbus originated in 1981.
The VXIbus is an instrumentation bus compatible (sort-of) with the VMEbus. The VMEbus specification specifies the physical dimensions of the boards, backplane and the chassis as well as the electrical specifications of the bus and various communication protocols.
In addition to the VMEbus, the VXIbus and Futurebus+ will be covered in this document in the future.
A PMC (PCI Mezzanine Card) is a proposed IEEE specification for a low profile mezzanine expansion bus for VMEbus, Multibus II and Futurebus+ systems. It has a 32 or 64 bit bus and has the same electrical specifications as the PCI bus (Peripheral Interconnect Bus).
There are over 200 vendors supplying products to the VMEbus community. VMEbus suppliers are most active in the USA, Germany and Canada and range from large corporations to small custom shops. Specifying a VMEbus system releases the user from the expensive, time consuming and sometimes (often) risky business of in-house hardware design.
Information resources for the VMEbus come mainly from three sources:
VITA, the VMEbus Systems Magazines edited by John Black and the
manufacturers. All prices quoted are in US dollars.
The backplane can have up to 21 slots providing the J1 connectors for the boards to plug into. The J2 connectors (if required) can be supplied with a second backplane board or in one piece with both J1 and J2 connectors. A J1 (on the backplane) matches to a P1 (on the board) and a J2 to a P2. The spacing between slots is 20.32 mm (0.8 inches).
Power is supplied to the VMEbus board through P1 and P2 (if used). The DIN plugs used are arranged in three rows (A, B, C) of 32 pins on 0.1 inch centres. These plugs are approximately 0.85 mm wide and 84 mm long.
P1 supports 16 and 24 bit addressing and 8 and 16 bit data paths. P2
uses the centre 32 pins to support full 32 bit data and addressing
paths. The two outer rows of P2 are user defined and are used for i/o
ports, disk drives and other external peripherals.
Notes:
The VME64 standard adds many other advanced features. VME64 is a VITA Standard. This standard, which has recently gained ANSI approval, is backwards compatible with existing VMEbus boards. For more information: http://www.vita.com/jvita.html
There is a VME64 Reflector (mailing list). To subscribe Email to majordomo@syspac.com leaving the subject line blank with the following command in the body of the message: subscribe vita You will receive a confirmation of your subscription and to address Email to others on the list send your message to vita@syspac.com
The VXIbus expands on the VMEbus so the two bus specifications are very
similar. TTL and ECL trigger lines, a local bus and an analogue summing
bus are among the added features. The December 1988 issue of "VMEbus
Systems" contains a good outline of the VXIbus. The Spring 1995 issue
of "VXIjournal" is a VXIbus Buyer's Guide.
There are two more board sizes in addition to the VMEbus single and double sizes:
opt = optional
P1, P2 & P3 are the same 96 pin DIN connector as in the VMEbus.
The increased width of the C and D sizes are to accommodate thick
analogue modules and EMI shielding.
The VXIbus uses the same pin assignments on P1 and the centre P2 pins as the VMEbus. The two rows (A & C) on P2 that were user defined on the VMEbus are assigned on the VXIbus. Features added include ECL (emitter coupled logic) and TTL trigger signals, a 10 Mhz ECL clock, more supply sources (+-24, -2 and -5.2 volts), an analogue summing bus, local bus lines and a module identification line. The optional P3 available on the D size board offers the same type of resources as P2 but at a speed of 100 Mhz (P2 is only 10 Mhz).
Reasons why the VMEbus and the VXIbus specifications are not totally
compatible include:
A VXIbus system can have up to 13 modules consisting of a central timing
module in Slot 0 and a maximum of 12 additional instrumentation modules.
to be continued.....
This magazine is free to qualified VMEbus systems users and specifiers
in the United States and Canada. There is a subscription fee applicable
for other countries. This magazine contains industry news, informative
articles and useful advertisements. Back issues are available from
Micrology. For more information see http://www.primenet.com/~magpub.
The December 1994 issue is a useful Buyer's Guide.
Email address: vxijournal@aol.com
Published by the people at the VMEbus Magazine at the same addresses.
Subscriptions are free to qualified users of the VXIbus or GPIB in
Canada or the USA.
To get a subscription request form for any of these magazines, send Email to John Black, Editor (micrology@aol.com) or contact the offices in Michigan.
The World Wide Web (WWW) site for these three magazines is:
http://www.primenet.com/~magpub.
A VXIbus Buyer's Guide - $33
Back issues of VMEbus Systems Magazine are available for $4 each. Email micrology@aol.com and request a listing.
*** Micrology is having a sale on some back issues** (still??)
The Systems Engineer's Handbook:
A guide to building VMEbus and VXIbus systems:
John Black has edited this hard cover text that covers the VMEbus and VXIbus thoroughly. This is an easy to read book that contains the complete VMEbus and VXIbus specifications and information on graphics, disk interfaces, Ethernet, image processing and interfacing to external devices such as stepping motors...and much more.
]It is now available direct from Micrology for US$59.95 + $7 shipping.
Phone (602) 966-5936 FAX (602)-968-3446 Email - micrology@aol.com
| VITA |
VITA Europe |
| 10229 North Scottsdale Rd |
P.O. Box 192 |
| Suite B |
5300 AD Zaltbommel |
| Scottsdale, Arizona 85253 |
The Netherlands |
| (602) 951-8866 |
31.4180.14661 (or .16593) |
| (602) 951-0720 (FAX) |
31.4180.15115 (FAX) |
| John Rynearson |
Zoltan Hunor |
| Technical Director |
Director VITA |
| VITA USA |
Europe |
| techdir@vita.com |
hunor@knoware.nl |
World Wide Web site: http://www.vita.com
VITA is the world-wide association of the VMEbus users and manufacturers
and as such organizes global promotion of the VMEbus including
exhibitions, seminars and courses. Vita does not test and approve
components but is a full member of ANSI and promotes standards of
interest to the community. VITA publishes various magazines and manuals
about the VMEbus.
In Europe, VITA has a mailing list of 100,000 engineers.
| VMEbus Handbook |
$53 |
| VMEbus Specification |
$32 |
The Handbook provides information for programmers, system integrators, engineers while the VMEbus Specification provides more "hardware level" information such as that needed for board design. These two books provide the information needed to understand the VMEbus system and are worth the moderate cost.
VITA also publishes a Buyer's Guide for $55 (or $110 a year).
VITA now offers a quarterly news publication, the VITA Journal, on a
complimentary subscription basis. It contains member and industry news
and the activities of the VITA Standards Organization.
]
275 Washington Street
Newton, Massachusets 02158
Phone (617) 558-4671
Fax (617) 558-4470
Email: tmw@cahners.com
Many VMEbus CPU boards have a built-in monitor program similar to the
TUTOR monitor and have a RS-232 port that can be hooked up to a terminal
or a host computer. Programs can be entered with the provided simple
assembler/disassembler and executed. Peripheral devices can be attached
easily to these boards. These boards are often available used and the
older ones with 68000/10 CPUs have a low cost(<$50) and this is a good
way to become acquainted with the VMEbus. See the FAQ for comp.sys.m68k
for more information.
There are many links between each of these sites. DR. BUB (DSP information) is not operational yet.
| VITA |
- http://www.vita.com |
| Heurikon Dallas Semiconductor Maximum Strategy Inc. |
- http://www.heurikon.com (nifty daily cartoons) - http://www.dalsemi.com (Postscript data sheets) - http://www.maxstrat.com (disk arrays) |
| ]Hitex Corporation - Titan Electronics |
http://www.hitex.com/automation for California http://www.ba-karlsruhe.de/automation (Germany) In-circuit emulators and remote debuggers. http://www.titan.com |
Introl is offering a non-commercial license for their US$2,000 C compiler. This is the full version - it is not crippled. It comes with an instruction manual. See their homepage for more information. This is now available in a Windows 95 version.
FAQ - comp.sys.m68k: for information on the Motorola M680x0 and MC683xx
ftp://nyquist.ee.ualberta.ca/pub/motorola/m68kfaq
http://www.ba-karlsruhe.de/automation/FAQ/m68k Germany
http://www.hitex.com/automation/FAQ/m68k California
http://www.oritools.com/info (also 8051, HC11 and PowerPc FAQs)
A frequently asked question is "are there any easy-to-use devices to
provide a VMEbus interface to my computer design?". Two suppliers of
chips to do these tasks are Cypress and Newbridge .
Newbridge also make PCI to VMEbus interface ("UNIVERSE")($US160 @ 1K) and Futurebus+ interface chips ("LIFE"). A new part, "TROOPER" is a low cost ($40 1995 @ 1K) slave-only VMEbus interface chip. Available June 1995. The SCV64 and "TROOPER" are fabricated by Motorola.
The "SPANNER" is now in production. This is a MC68040 to PCI bridge chip. This is Newbridge's introductory offering in this area.
(800) 267-7231 (North America), (613) 592-0714 in Canada or (408) 258-3600 in California.
Email addresses:
nms-inquire@newbridge.com for general inquiries or
nms-support@newbridge.com for technical support.
<prices may be inaccurate> The SCV64 (33 Mhz QFP) has been reported as costing US$ 332 (qty=5), US$ 287 (25) and US$ 248 (100).
Cypress manufactures a series of useful VMEbus integrated circuits:
San Jose, California, U.S.A Toronto, CANADA. Phone (408) 943-2600 Phone (416) 620-7276 FAX (408) 943-2741 FAX (416) 620-7279 vmebus@cypress.com Ed Dupuis (ead@cypress.com)
BBS: (408) 943-2954 (1200 to 19.2k, 8N1)
The MK48TO2B-25 is being discontinued and perhaps replaced by the M48TO2-200PC1. Mauser Electronics <(800) 346-6873 or (817)483-4422> nor Arrow have any MK48Ts and the M48Ts have a delivery time of 8 to 14 weeks. MOSTEK is apparently now owned by SGS-Thompson who will be replacing the MK48TO2B with a 2 piece part called the "SnapHat". The IC proper and the battery/crystal are replaced separately. This information is provided by Gerry Belanger and Dennis Johnson.
Dallas Semiconductor makes the Timekeeper series of clock chips. Their US phone number is (214) 450-0448 or (800) 336-6933. The Dallas DS1642 may be replaced the Mostek MK48TO2B-25<not confirmed>. The DS1642 is available in speeds of 120 or 150 nsec. It is available directly from Dallas Semiconductor for about US$17 plus shipping with a delivery time of 4 to 6 weeks. Dallas suggests that Newark Electronics may have this item in stock. (800) 463-9275 CANADA only.(?)
The MK48TO2B-25 Mostek real time clock consists of a standard 24 pin DIP with a black plastic cap attached to its top. This plastic restangular cap contains the clock crystal and the battery.
This cap is attached at each end only with some sort of potting material that seems to be an epoxy. If you put the MKT48 up to a light source you should be able to see a gap between the plastic cap and the DIP. Notice that the cap is glued to the DIP only at the ends and then only in the centre of the ends. ie where the half-circle is molded into a DIP to indicate where pins 1 and 24 are and at the corresponding place at the other end.
The wires for the crystal and the battery pass through this potting material on each side of the potting material. The crystal wires are at the pin # 1 and 24 end of the DIP and the battery is at the pin # 12 and 13 end. These wires do not necessarily connect to these pins.
The idea is to cut through the potting material, disconnect the positive internal battery wire and solder a new battery to the wire coming out of the DIP nearest to pin 13 and the other to pin 12 (ground) of the DIP.
The positive (+) wire is towards pin 13 (but is not connected to it). Ground is pin 12 (the external pin on the DIP).
I found a hacksaw blade the ideal tool to slowly cut through the potting material. From time to time I would probe in the cut spot with a voltmeter (gnd to pin 12) to see if I had reached the positive wire. Even though the battery is near death, mine measured 0.9 volts which is enough to detect. Then I continued cutting and scratching until the wire was exposed. The rest is easy. Cut the wire in two and solder the positive terminal of the new battery to the lower wire (ie the one that comes out of the DIP). The wire is not microscopic and relatively easy to work with once exposed.
A picture would be worth a million words, nay, a -billion- at this point. Once you have done one, it would be easy to do many. I used a small 3 volt clock battery that had two tabs spot welded on it. Works great for me! Good Luck!
Please send suggestions for this article to r.boys@genie.geis.com
The original idea for this was provided by Michael Coughlin at MIT.
In 1981, when Motorola agreed to allow Mostek and Signetics to second source the MC68000 microprocessor chip, the three companies agreed to meet and discuss the possibility of supporting a common backplane bus. At that time Motorola had already developed a 68000-based backplane bus, which they called VERSAbus. Since I had written a large portion of the VERSAbus specification, I was the Motorola technical representative at that meeting.
Motorola proposed that the three companies jointly support the VERSAbus backplane. However, both Mostek and Signetics rejected that proposal, saying that the VERSAbus board size was much too large. In response to that objection, Motorola proposed that the (much smaller) Eurocard board size be used. A backplane could then be designed with the VERSAbus electrical specifications and the Eurocard mechanical specifications. Motorola suggested that new board products (based on this new backplane) be called VERSAmodule Eurocards, which could be abbreviated "VME".
Both Mostek and Signetics were satisfied with the choice of the Eurocard mechanical standard, but they objected to the "VERSAmodule Eurocard" name, since Motorola had already trademarked the name "VERSAmodule".
Eventually this difficulty was overcome when the three companies agreed
that the name VMEbus would be placed in the public domain, and that if
anybody asked what VME meant; they would say....
"VME?...Oh, it doesn't stand for anything in particular".
Now you know the awful truth.
by: John Black Editor VMEbus Systems Magazine Tempe, Arizona micrology@aol.com
(reprinted here with John's permission)
Next month (hopefully) will be Pivotal Graphics.
Most Friendly Contributors:
Andy Fraser Ontario John Black Arizona Michael Coughlin Massachusets (sold me my first VME board!) Gerry Belanger Connecticut Bosco Chan Ontario Michael Bodine Ilinois
and more to come.....
Please send all comments to:
Robert Boys
HiTOOLS Inc
2055 Gateway Place
San Jose, California, 95110
r.boys@genie.geis.com or rboys@best.com
Thank you