What is the VME chassis and backplane ?

hai

what is VME chassis?? and what 4U, 6U or 9U inidactes in datasheets?? and what is backplane??

supplier of vme chassis & controller

Hi Ranganath,

ur questions are "what is VME chassis?? and what 4U, 6U or 9U inidactes in datasheets?? and what is backplane??"

Backplane is a PCB which provides mechanical and electrical connectivity between several other PCBs. For example Motherboard in a PC is a Backplane, where we can insert PCI or ISA or other type of daughter cards in the respective slots on the Motherboard.
There are 2 types of backplanes, one is active and another is passive backplane. Active backplane usually have some circuits and components on them. But Passive backplanes doesn't (some times u can find some components, they may be termination chip resistors or voltage regulators). PC Motherboard is a Active backplane which carries, Processor, North and South bridges etc.
Passive backplane contains only copper traces for electrical and data links and slot connectors. More on that later.

VME Chassis is a Metallic box or enclosure which normally contains VME Backplane, cooling systems like fans and Power supply unit like SMPS. VME backplane only contains copper traces, Slot Connectors and terminations. It is a Passive type. Very first VME bus is designed by Motorola for its 68K Processors. VME bus is told to be the most complex Time shared bus ever made. It's arbitration process is complex than any other buses. It can transfer datas of various word lengths from 64 to 8 bit. Lesser the word length, more the baud rate.
It has the facility to provide Priority to different Slots. Maximum no. of slots on a backplane is 21.
Any bus system needs some device to act as arbiter or controller. In PC Motherboards the Processor and the South bridge takes care of the PCI Bus arbitration. But in Passive backplane buses, user has to put a appropriate hardware running the software which does this job. In VME bus slot 0 (First slot) card should do this functionality.
Passive backplane are scalable. For eg. VME need not contain 21 slot always. Depending on requirement the Backplane size can be reduced, or slots can be left free for future upgradation. V
VME is told to be the most reliable bus too. Hence you can find it in most of the Military systems. Compared to latest buses its slow but very reliable and scalable. There are many versions of VME, the latest one is VME 320. The most widely used nowadays is the VME 64x. Very first VME transferred 32 bit datas, now it can take 64 bits too. VME 64x can even provide a facility called Geographical addressing and Hot swapping capability. You can remove or insert a VME card in the slot without switching it off. Normally the slot 0 card is called the "System Controller". The System Controller access other cards by its range of addresses. These addresses are independent of the Slot in which they are installed. But "Geographical addressing" in VME 64x seems that it provides additional addressing capability based on the Slot too.

There are 3 type of Cards on a VME System, a "System Controller", Master and Slave. A VME System can contain only one System Controller, atleast one Master and any no. of Slaves. System Controller takes care of Arbitration. Master initiates Data transaction between Slaves or Slave to Master. There may be group of slaves controlled by a Master.

All these operations are not done default. The user has to write the software in such a way for the required operation. Conflicts between Softwares of 2 different boards should be avoided. These things comes under Large Scale Embedded Software development. Its a interesting and practical system which very few people know (I think so) that too only in Military and Aerospace industry.

Next is about "U". There are different size of VME Boards. 3U is the smallest which contains only one Back plane connector (P1). It can do only 32 bit transactions maximum. For this please refer the website www.interfacebus.com

Still lot of things are pending on this interesting VME system. I can't tell all those thing here in one shot. But I too know that the information on the internet is either insufficient or not clear on VME things.
The best thing is to download every thing related to VME, VXI,PMC, cPCI, ATCA etc. from www.interfacebus.com and compare between them. You can eve see the bus lines of VME and analyse about their arbitraion process. You will feel that they are more reliable. Any other doubts or discussions u can mail me. I too learning and exploring more. Even Fighter Jet's Core Avionics computer, Radar Computers, Nuclear Reactor control systems, and things alike use VME for its Reliability.

Emails: srinivasan_b1@yahoo.co.in
srinivasan.b84@gmail.com

All the best for a interesting, thrilling and knowledgeful career.

By Srinivasan .B

avionics vme computer chassis

Hello Ranga,

VME means: Versa Module Europe
3U stands for 160mm X 110mm
6U stands for 160mm X 220mm

Some people call Back plane as motherboard

If you need more details, don't hesitate to contact me.

regards,

N.Muralidhara
CRL-BEL

vme srinivasan

'U' is a unit. 1U = 43.60mm. And in VME Cards 6U,3U etc. mentions the card's length or height. The breadth is indicated by another term 'Size'. 6U Size 'B' is most prevalent. For correct information with pictures visit

"http://www.interfacebus.com/Design_VME_Card_size.html"

Bye.

Thanks & Regards,
Srinivasan

passive vme backplan + termination

if we want to read continuously from mail box memory of IP module how to write a program to handle interrupt please tell me the logic .means after setting values in all interrupt registers it will automatically handles the interrupt or else we have to give condition like if newdata register have some value like that
i hope that you will help me.

thank you,

Added after 2 minutes:

sorry my IP module is IP330 carrier is AVME 9660
ok than you

Added after 1 minutes:

this is priyadarsini

Added after 26 seconds:

i want in Clanguage