PCB with Virtex 5 FPGA's - Page 1
Forum section: electronics / general

author: diracshore
author_rank: Regular Contributor
timestamp: August 05, 2011, 09:09:01 am
content: Hey all,I have this PCB with some large virtex FPGAs that I am trying to access over a JTAG. I need to power the board but I don't have the schematics and I am not sure of the voltage or current. Can anyone hazard a guess ?https://picasaweb.google.com/109256068638376206526/UnknownPCBWithVirtex5LX330TAndLX110TThank YouThom

author: Unknown
author_rank: Unknown
timestamp: August 05, 2011, 08:55:00 pm
content: My guess would be based on the label on the Delta DC-DC converter. My guess is that the switcher on the right of it produces a lower voltage from the 5V for the FPGA core.

author: diracshore
author_rank: Regular Contributor
timestamp: August 06, 2011, 10:57:52 am
content: Thats what I was thinking but look herehttps://picasaweb.google.com/109256068638376206526/UnknownPCBWithVirtex5LX330TAndLX110T#5588043449693170178It seems there are some 125v components (yellow) by the 4 pin power plug.

author: Unknown
author_rank: Unknown
timestamp: August 06, 2011, 04:07:28 pm
content: Nothing strange about a fuse with some overhead in the rated voltage. Unless there is another converter between the Delta one and the power input (unlikely, why would someone go through the trouble of converting mains to ~40VDC?), I think it's safe to assume that the specs on the label are correct.

author: diracshore
author_rank: Regular Contributor
timestamp: August 07, 2011, 11:05:37 am
content: Are you confident the yellow components in the photo are fuses ?If that is the case then where can I get a power supply for this unit ? Are there cheap variable power supplies I can pick up ? If so is there a particular model that is reliable ?Can I buy a power supply specific to this units requirements ? Is that an ebay job or is there a catalog somewhere ?Is it typical to supply dc direct into a board such as this ? How do I discover the polarity ? Since its a backplane it may not have reverse polarity protection.

author: tinhead
author_rank: Super Contributor
timestamp: August 07, 2011, 12:14:25 pm
content: Quote from: diracshore on August 05, 2011, 09:09:01 amfor what ? Even if you manage to do it (which is actually simple) a WebISE edition is not good enoughto develop anything for such exp. FPGA. Additionally without tools (boundary scan) and knowledgeyou will probably destroy all 3 FPGAs (yes, there is 3rd one too) just because you can't just apply anything toi/o not knowing how they interconnected to other parts.Sure you can remove all these Broadcoms chips, maybe even some other components, use boundary scan tofind out the i/o attached to SRAM and fianlly build a nice logic analyzer ... but for that you willneed software and knowledge which you don't haveQuote from: diracshore on August 05, 2011, 09:09:01 amschematics, hehe ... no comment on thatQuote from: diracshore on August 05, 2011, 09:09:01 amas i said above ...Quote from: diracshore on August 07, 2011, 11:05:37 amyou need multiple lab power supplies.Quote from: diracshore on August 07, 2011, 11:05:37 amlolQuote from: diracshore on August 07, 2011, 11:05:37 amlol of the month ... do you a favour, use ebay and earn some money, there will be definitely someone who can reuseparts from that board.What you trying to do is like trying to repair and alien space ship, full of things you will never ever understandjust with a screwdriver and piece of bubblegum. This work ony when you MacGyver ...If you wish to learn something use to "power of google", all these DC/DC converters are good known things,there are datasheets available with pinout - so you will know the voltage/polarity/rating. Then alle these bigyellow caps on bottom side doea have polarity .. then all these oscilaltors and many many many other parts on thatboard are known (datasheet available). So to power up is really smallest problem you can get with that board,but as i said above, what then?

author: diracshore
author_rank: Regular Contributor
timestamp: August 07, 2011, 02:27:42 pm
content: Why do I need multiple power supplies ?

author: DavidDLC
author_rank: Frequent Contributor
timestamp: August 08, 2011, 08:21:19 pm
content: Tinhead, why are you sarcastic with somebody asking questions ?If somebody is asking questions, is because that person does not know about the specific matter and is trying to learn.Are you applying the forum rules ?I really didn't like the "lol" or "lol of the month" comment, hopefully we all start to apply the forum rules and be more respectful to others.I hope you are not the kind of person that will find this as an aggression on my side, but take this in the positive way.David.

author: tinhead
author_rank: Super Contributor
timestamp: August 08, 2011, 09:33:57 pm
content: Quote from: DavidDLC on August 08, 2011, 08:21:19 pmsarcastic? not at all, that was my best adivice i can give someone who is trying to destory 15000USD FPGAby playing with JTAG or power supply.As i already said, all these DC conversters are known, there are datasheets available, there is only little knowledgenecessary to read them and to apply right one supply. On the other side there is no way for beginner tohave any use of all these parts (ok, maybe except Actel Fusion and some small things).My advice is - when he really wish to learn something about FPGAs, to sell that board on ebay and buyproper development boards. I'm using (with some exception) only Altera FPGAs, but if i would use XilinxFPGAs i would probably buy such board for 200-300USD without even thinking too much aboutpotential risk. So for that money he will get definitely a nice dev board where he can learn more than enough,where he don't have to download warez and can easily use WebISE and so on.Quote from: DavidDLC on August 08, 2011, 08:21:19 pmyou don't have to like everything and everybody, and no, no big deal. I'm very patient person - up to a specific level.However these question he asked are telling me everythign i need to know about the knowledge level.And of course everybody started small and made many mistakes, i'm always helping ppl as much i can,but whe is see they on "suicide way" i'm trying only to stop them. And believe me, killing a 15k USD FPGAis like suicide, and will not help him to learn anything (maybe expect "shit, electronics is not for me").

author: DavidDLC
author_rank: Frequent Contributor
timestamp: August 08, 2011, 09:45:28 pm
content: Ok, good to hear that.

author: diracshore
author_rank: Regular Contributor
timestamp: August 09, 2011, 12:02:20 pm
content: Ok, couple of things to address.First yes I found some of tinheads comments abrasive. But I have learned to filter this type of thing when gleaning information from forums. I have to consider attitude irrelevant mainly because those people in possession of the most pertinent knowledge typically have character flaws, case in point. tinhead actually provided me a great deal of relevant info and for that I am grateful. But I hear what you are saying David.The board I aquired for $100. Also note they are ES / early silicon / engineering sample chips. And where $15k might be the going rate for the commercial version, from a US vendor say Avnet, the truth is those people who need ES parts can get the LX330 from the black market in Taiwan at about $300 a pop sans PCB, and the commercial version can be had from legitimate sources for about US$5k. Not that there would be much point in using virtex 5 vs virtex 7 in a new design.Now I don't know if these chips even work. So powering the board and connecting the JTAG is the path of least investment to verify that. I doubt that just hooking up a JTAG would kill the FPGAs and I know this type of hack has been done before. See here.http://nsa.unaligned.org/hw.phpI plan to try to use some of his techniques to commandeer the virtex FPGA's with just a few IOs. While I am not interested in hash cracking, the application I would use for these chips, assuming I get them running, would be risky in itself to the FPGA. Evolutionary hardware (my interest) requires a large fabric and it has to be expendable.I'm not a hardware guy and I need help with this stuff. I have a multimeter, a open source logic analyzer, and a small budget.The logic analyzer I plan to use you can see here,http://www.seeedstudio.com/depot/preorder-open-workbench-logic-sniffer-p-612.html?cPath=75Anyway Thanks to everyone for their time.Thom

author: tinhead
author_rank: Super Contributor
timestamp: August 09, 2011, 08:08:52 pm
content: Quote from: diracshore on August 09, 2011, 12:02:20 pm^^ Thom, you welcome.Quote from: diracshore on August 09, 2011, 12:02:20 pmno, that's the wrong way, just listen careful what ppl trying to tell you, forget any kind of emotionsand don't take personal any kind of comments.You can see this in a different way - ppl with more knowledge are probably older thanyou - so they will die firstQuote from: diracshore on August 09, 2011, 12:02:20 pmoki, then forgot my ebay proposal as you bought for reason.Quote from: diracshore on August 09, 2011, 12:02:20 pmas i said above, you will find in Virtex datasheet possible core and i/o voltages, additionally all these DC convertersare good known so not a big deal to find out which DC is for what voltage and how connected (FPGA or other things).You should as first step cleanup the board, there are some shrots, broken PCB, broken parts. I would alsoremove both Broadcom chip, the Netlogic chip, the PPC chip, the Vitesse chip,the Actel Fusion chip (you can reuse this baby, that's mixed signal FPGA (probably - i don't see exact) with ARM core)and eventually the small board with PIC controller - this is, let me gues, power contolling unit.You have multimeter, so you can check if Dc converters power good/enable pins are routed to that small board.Then take a closer look on the small chips, look for configuration devices - when non there then the firmwareis uploaded by µC/CPU or Actel Fusion (however it will be somewhere stored).In any case you have then to find the JTAG plug/pins/signals - with some luck easy job.Having cleaned-up board you can then play with powering up. My proposal does not have anythign to do with pure powerconsumption, the last thing you need is a FPGA with loaded firmware or chips locking pins .. why see below.Quote from: diracshore on August 09, 2011, 12:02:20 pmto scan the chain over JTAG will not destory anything ... but (see below) ...Quote from: diracshore on August 09, 2011, 12:02:20 pm... something like boundary scan can definitely shot some pins.During boundary scan you can check the register to see their status, but you can also changethe i/o cell (actually pin) status. So when two chips are driving as output the same wire between them youcan easily burn both.My proposal, there are profesional tools like Universal Scan from Ricreations - use such tool.The 30days version is good enough ... when you need more use google.In this tool you can easily play safe with boundary scan, monitor pin status and apply (in extest mode) somevalues to pins to check interconnectivity between FPGAs and other chip (or the pads where these chip was soldered).Quote from: diracshore on August 09, 2011, 12:02:20 pmthis tool was designed to make boundary scan easier on a bord with MULTIPLE FPGAs or Boundary Scan capable chips,believe me it is a hell of work when you have more than one chip to reverse.On your board there are 3 FPGAs, but probably not even connected together - additionaly bunch of chips without JTAG.So forget that tool, unsolder these few parts (or maybe even more - however i can't see allof them detailed to tell you what can/can't be removed) and use Universal Scan to testthe "free" i/o pins. When you have some chips removed you can then see in universalscanwhat is the status of input cell - based on that (when they not changing after power up - that's why you shouldfind the way how the FPGA design will be uploaded, to interrupt it) you can create a map of free i/o pins,then set them to Z and measure the free pad voltage . if something connected the voltage will be different as when nothing connected ... there are many tricks you can use,a nyway, let's start first with power supply.Quote from: diracshore on August 09, 2011, 12:02:20 pmso then it make sense to remove all unnecassary chips, as i said above.Btw, you can leave these GSI memory chips soldered - you might have a use for them, fast memory (even if these FPGAs are huge)is always good thing.Quote from: diracshore on August 09, 2011, 12:02:20 pmsmall budget = hmm, with some luck you will need only one input voltage for all DC converters.multimeter = be careful, some multimeters have much too high voltage while in continuity test mode.To high voltage will shot i/o pins, check first the manual or measure (when you can) the voltage.I'm using continuity tester with 0.3V, so even with wrong polarity nothing can be damaged.When i look on my multimeters, some have 10V while within continuity test .. this is of course overkill.The best would be below 0.7VQuote from: diracshore on August 09, 2011, 12:02:20 pmoh yeah, that's the Sump modified design. Actually you could use the small Virtex to buld a kick-ass Logic Analyzerbased on that Sump design but you will need ISE license, the web edition will not work .. ups, you need it anyway.

author: diracshore
author_rank: Regular Contributor
timestamp: August 10, 2011, 01:44:24 pm
content: That is incredibly helpful. I have a very clear idea of a plan now.Thank You 1000 times tinhead !