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Ok to start off I am not a electrical engineer!!! If you use these designs and your fpga blows up I will not be held accountable!!! Use at your own risk!!! Having said that I do have some experience with electronics... mostly repairing and hacking old gadgets...

If you are a electrical engineer and see something wrong with these schematics PLEASE let me know! I don't think I'm going to be able to test them for awhile because of the high financial cost....

If this post is useful to you please consider donating a small amount:   1BNFvb7e62j5CANx1WARq5jADaXJ6uVhZa


I am still working on routing the connections for the small plugin board! When I'm finished I'll update the download link!

Now for some pictures!

http://img404.imageshack.us/img404/5257/unpopulated2.th.png (http://img404.imageshack.us/i/unpopulated2.png/)
http://img593.imageshack.us/img593/2633/populated.th.png (http://img593.imageshack.us/i/populated.png/)http://img831.imageshack.us/img831/2503/populated2.th.png (http://img831.imageshack.us/i/populated2.png/)
http://img849.imageshack.us/img849/3886/unpopulated.th.png (http://img849.imageshack.us/i/unpopulated.png/)





Part list:

Part	Value	Package	QTY	Price
C1	0.1uf	0402-CAP	2	$0.04
C3	4.7uf	0805	1	$0.02
C4	330uf	PCK0G331MCO1GS	5	7.5
JP1		JP2	3
PL1		5566-16	4	12.80
R1	4k7	0805	1	$0.02
R2	10k	0805	1	$0.02
R3	619ohm	0805	1	$0.02
R4	2k	0805	1	$0.02
U$1	USB-MINIB-5PIN	USB-MINIB	1	$1.00
U$2	D12F200A	D12F200A	1	$30.3
U1	FT232R	SSOP28DB	1	$4.5
U3	OKR-T10-W12	OKR-T10-W12	1	$10.00
X1	9090-4V	9090-4V	1	$1.00
PCB	PCB	PCB	1	$20.00
TOTAL:	87.24

Data Sheets:

Spartan 6                 http://www.xilinx.com/products/silicon-devices/fpga/spartan-6/lx.htm (http://www.xilinx.com/products/silicon-devices/fpga/spartan-6/lx.htm)
FT232R                     http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT232R.pdf (http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT232R.pdf)
OKR-T/10-W12           http://www.murata-ps.com/data/power/okr-t10-w12.pdf (http://www.murata-ps.com/data/power/okr-t10-w12.pdf)
D12F200                   http://www.delta.com.tw/product/ps/dcdc/std/download/data_sheet/DS_D12F200_11042008.pdf (http://www.delta.com.tw/product/ps/dcdc/std/download/data_sheet/DS_D12F200_11042008.pdf)

USB Interface:
This board uses the FTDI FT232R , this chip was chosen because its cheap(about $4),easy to use, and its the same chip used by the x6500 so there is already software written for it.

Power supply info:

This board uses the D12F200  DC to DC converter for the main core power supply. This converter was chosen because it is cheap(around $30), it can output 40 Amps, and it comes with a 2 year warranty!

Why do we need a output of 40 Amps? The Spartan 6's core runs at 1.2v and each Spartan 6 consumes around 10 watts a piece. This board supports 4 Spartan 6's so its pulling about 40 watts... Lets do a simple calculation to see how many amps that would be.

A=W/V
A=40/1.2
A=33.33333333333333

This is why we need 40 Amps....

First let me say, I'm glad you released this :)

It's nice to see others working on designs and sharing them (even if they may not be perfect lol).

I also like the super "spartan" approach (minimal board, modular via backplane and so on). It's similar to an approach I'm taking in my own design.

I haven't looked at the PCB/Schematic in detail, though at first glance I suspect the following will be big issues:
- Your FPGAs are pretty close together. Judging from the cooling needed on other designs (on both the back of the PCB and the chip via heatsink) you're going to need more space between them. But that's just first impression.
- It looks like you're only using 0.1 DIL headers for the backplane? and if so you're only using 2 pins per power line? I'm a bit concerned about the current you're jamming through those pins. (and relatively small traces). Remember that a mining FPGA can draw upwards of 10W per chip (I realize that's divided across the power lines, but VCCINT will take the brunt of it)
- Can your voltage regulators handle the draw from all 4 FPGAs? (it does look like your VCCINT reg is rated for 40A which should handle it, but to be considered. Also are you isolating powerline noise well enough between FPGAs?

I personally hope this design works out well, just throwing some feedback out there ;)

The connectors in the 3d renders arnt the actual ones in using. I'm using these:

http://search.digikey.com/us/en/products/15-24-7160/WM17742-ND/1633805

these connecters can handle alot more than im putting through it and VCCINT gets 4 pins VCCIO gets 4 pins Ground gets 4 pins and the last 4 are for jtag

also look at my update in the post about the power supply 40 watts at 1.2v is around 33 amps

and regarding noise I'm following all the guidelines in the Spartan 6 PCB and pin planning guide on using low esr capacitors

I do think the cooling may be a problem though it might be good to space them out a bit more they are spaced a inch apart

EDIT:

Btw my power traces are huge lol I dont think you noticed but check out this pic of the bottom of the board

http://img268.imageshack.us/img268/6672/eagleuptestboardbottom.png

I love it but honestly I would like to see a "bigger one".

PCIe 6/8 pin connector is good for 150W.  I would love to see a backplane which gets power from a PCIe 8 pin "socket" (and can work with either 6 pin or 8 pin connector, usb controller for connection to a host, and a 120W 12VDC to 1.2VDC supply and 12 (yes 12) connectors.   

Each board would have only a heatsink no fan and you could put 2x 140mm fans along the "long side of the board to blow cool air across all the heatsinsk.  The board could have L brackets (or just screw holes) to mount the fans and 2x 3pin fan headers to power the fans.

210 MH/s * 12 = ~2.5 GH/s fully loaded and user could add daughter cards incrementally.  An 900 to 1200W PSU w/ 6 PCIe power connectors could power 6 boards or 12.5 GH/s.  It could be a "poor mans" Rig Box.  Start small w/ one backplane and 4 or 6 FPGA and build as you go.

Well actually I don't think a whole bunch of pcie connectors are needed...... my model here should only be pulling about 3.5 amps at 40 watts on the 12v line normal molex connectors like im using should be able to go up to around 35-40 amps max on the 12v line as long as the power supply can handle it. although I wouldn't recommend that as you would be pulling like 400 watts off one wire

EDIT:
errr..... well it depends on what gauge the wiring is im not sure what is normally used on molex

Watching closely...

Well it isn't a "whole bunch" just 1 PCIe connector per backplane (12 boards).

The reason to use PCIe connector instead of Molex is simply a practical matter instead of a technical limit.

Most PSU are designed to give full amperage of a rail to a pair of PCIe connectors.  On the other hand all the Molex connectors and likely either ATX24 connector and/or 8pin MB supplemental connector are usually all crammed on the same rail.

Even in single rail designs "virtual rails" are often used to limit current on one "set of wires".  So as a practical matter it is pretty easy to push 900W to 1200W over 6 PCIe connectors (1 per backplane).   If you had the same 1200W PSU and tried to pull 900W from the Molex connectors you would find the PSU would trip off.

Maybe not all PSU would but a lot would.  Trying to find the "right" PSU then becomes difficulty.  Using PCIe connector is simply a "practical solution".  If a PSU had 4 PCIe connectors it likely can power 4 boards, 6 connectors = 6 boards.  Doesn't take a lot of trying (and failure).  Just plug and go.

I understand Molex connector can handle a lot of amperage but most PSU aren't setup to deliver max amperage on Molex connectors.  In modern computer almost nothing uses them anymore except fans.

I see lol I thought you meant like a couple per board.... when I started designing this I was thinking of using a cheap $25 300 watt single rail PSU

Yeah maybe Molex would be fine.  I guess one could use a custom PCIe 6pin to Molex adapter.  For a large backplane though might need to do some testing to see how much amperage most PSU can push on a single wire.  Sure the wire and connector can handle it but most PSU may not be designed for such a high load on a single wire.

Maybe they are and the whole thing is just academic. :)

Check this out

http://search.digikey.com/us/en/products/D12S300-1%20C/941-1046-ND/2501318

you could throw 2 of those on a board and have enough power for 14 spartan 6's

and its only about $10 more than the regulator i got on this small board

Nice.  Yeah 14 daughter boards.  Drool.

Got a guesstimate on what just the backplane would cost w/ 14 connectors.  $80? $200?

It all depends on how many youd want to make......

stuff is ALOT cheaper in bulk..... you would also prob need around a 12 x 5 PCB which could be pretty expensive in small qty even these connectors are over $1 cheaper a peice if you buy like 50

I'll do a rough estimate for 3 boards for you

Watchin

so heres a rough estimate:

50 female connectors 137.75
50 male connectors 114.57
6 psu         250.56
3 FT232R     12
50 330uf     22.33
3 5x12 pcb      60
3 pcie connectors        3
rand caps & res  5
fuses         3
anything im forgetting??? 10


            618.1033
                   618.1033/3 = 206.0344333333333

However I didn't factor in the power supplies for VCCIO bc im not sure what exactly youd need for 14 chips =p but id expect it to be a extra $20-$30 per board

18 awg for a standard good quality molex.

Are you talking about 4-pin HDD molexes, or 6/8 pin PCIe connectors? My PCIe 6-pins are all 16AWG from a PSU I have here.

The 4 pin molex, since that was what the OP has on his render.  16 awg is used as well for high-end PSU's (Primarily used for PCI-E and the 24-pin ATX connector.)  That said, IIRC 18 is standard fair, but 16 allows greater wire length without a noticeable increase in resistance.

I've seen "shitty" adapters use fine strand 20awg, and if you see threads where adapters have burned out, this is usually the culprit from what I've seen.

If I find some time in the next couple of days I'll take a gander at the data sheets and your design.  

Just curious, have you done any circuit analysis on this yet?

I think glasswalker covered the off-the-top of my head concerns.  It'd be nice if you could isolate the VCC input for each core.  

I might also think about using two 30 amp DC-DC converters instead of the single.  Doing so would give you some head room to add a header at each core location for a fan if ever there was a desire for it.  At 33.3/40 amps you're not leaving yourself a lot of room for other losses in the circuit(s) as well as a the converter dies you don't lose the whole board.  

Non-EE note:  Holes for heat sinks on each core daughter card.

No I haven't done any circuit analysis on it... can you recommend a program?

Just wondering..... Why would I want to hook up fan headers to my converter thats running at 1.2v and put more load oon it when there is perfectly good 12v and 5v lines coming from a PC power supply?

This.  All that is needed is a 2pin male fan connector and a trace to the 12V input.  Nothing more complicated than that is necessary. 

You're both completely right, brain fart as I wrote the reply in a rush.

I'm partial to using PSpice, but that's just because it's what I was taught.

Hi stcupp thanks for sharing your DIY design with the community.

I'm a hw-engineer, and also quite experienced with EAGLE.  I did not yet look longer time on your design. Maybe I will find some time this weekend.

But a few thinks directly came into my mind.

You mentioned to choose the FT232, because it will already be used in other FPGA miner designs, so you expect to be compatible with the other bitstreams.
Unfortunately I also haven't looked how it will be done in the X6500 design, so maybe my worries are stupid, but did you check that the wiring between the FT232 and the FPGA's is exactly the same?
From your signal names it looks like you would like to use the JTAG pins of the FPGA's for communication. Is this how the X6500 design is doing the communication? Are you sure it doesn't matter for the existing mining-software/bitstream if there are 1,2 or 4 or even more FPGA's in the chain? I don't know how you wire the daughter boards with the FPGA on board, but from your backplane I can see that the TDO (output) of one daughter board is not going to the TDI (input) of the next board and so on (JTAG chain). All TDO's/TDI's are on the same pinnumber.  I don't understand this kind of wiring.   

Not really a good choice...
It isn't. And the X6500 will move away from using the FT232 soon, because that's really awful from a software point of view.
Yes.
The current software for the X6500 only supports one setup: 2 FPGAs, hooked up to one set of JTAG pins each. Multiple devices in a chain aren't supported, and there is no reason to add support for that because that whole interface will be redesigned.
That looks just broken.

Ok, so it looks that stcupp's current design will not work with existing bitstreams of other designs and has to be changed. This feedback should help him.
It looks like stcupp has to decide if he would go one with a design >2FPGA's and if, he has to change his wiring (maybe use multiple FT232's in his design, 1*FT232 per 2FPGA's), then it should look for the existing software simply like multiple FPGA mining boards.
Or he is thinking about another solution then 1*FT232 per 2FPGA's. In this case he has additional HW design effort (maybe a uC), the mining sofware has to be changed and maybe also the FPGA bitstreams. This is all together a lot of work, especially if you have to do it alone.
I just took a quick look on the newest X6500 rev3 design (picture of the board). Even on rev3 is still a FT232.

TheSeven, do you know what is planned as a replacement for the FT232 solution in newer designs of the X6500?
Or what to you recommend stcupp to use between his FPGA's and the Host-CPU?

ZTEX is using a Cypress uC, but his design only handles one FPGA.

Yes, the rev3 is basically a rev2 + temperature sensors + fan headers + heatsink mounting holes, there haven't been any interface changes.
The next generation will have a µC, most likely some STM32 part. Those are very well capable of handling 4 FPGAs, or even more if desired.

I just don't think you'll be happy with an FT232-based solution.

We really need a Spartan6 mining core hard macro, so that you can resynthesize just the interface part without affecting the mining core itself. That would make adapting the FPGA bitstream to different PC interfaces a lot easier.

Ummm... DAT, the ATX spec regulates the GPU power consumption, not the connector itself.
The fact that a GPU is lmited to 75/150W does not imply the connector itself can't deliver (much) more power.

The PEG-6 connector is actually the Molex Mini-Fit Jr connector (http://www.molex.com/molex/products/family?key=minifit_jr&channel=products&chanName=family&pageTitle=Introduction#related) configured with HCS contacts. These are rated for 13A each.
With three 12V wires/contacts, you're looking at 3*13*12 = 468W max theoretical load.
To be on the safe side, take 80% of that value and you are looking at 375W with a single PEG-6 connector.
The PEG-8 connector is pretty much the same as PEG-6 as the number of 12V wires/contacts is unchanged.

Before I made this design I looked into the FT232R a bit and how it works with the software....

The current software x6500 wouldn't work because the jtag connections on the spartan 6's arn't daisy chained together so yes there would have to be a little bit of software modification.....

The x6500 actually uses 2 different jtag chains 1 for each spartan 6.

And the reason the FT232R isnt really a good chip choice is because it doesnt support jtag! they're using bitbang mode on the chip to use jtag

http://vak.ru/doku.php/proj/bitbang/bitbang-jtag

Also the chaining on my board isnt broken lol thats what the jumpers are for the middle pin goes to the tdo of a spartan 6 and you can jump it to either go back to the tdo of the ft232r or jump it to go to the tdi of the next spartan 6.

This makes it so you can just add spartan 6 boards  and wont need all 4 to complete the daisy chain

say you only got the money for one spartan 6 and youd jump the tdo back to the ft232r

but then you add another spartan6 so youd jump the first jumper to the tdi of the second spartan6 and the second jumper back the the ft232r.

But think about that a little harder.  What is on the other end of the wire.... the PSU.

The spec doesn't just regulate the GPU it also regulates the power the PSU must deliver.

What assumption was the PSU built for?  375W or 150W?

Assuming you can pull 375W from a connector just because the connector is rated for that is not going to make a very useful product.

Plug in, power on, instantly PSU powers off  or plug in, power on, PSU smokes.  

150W is plenty.  It can power 14 FPGAs and would work with 99.9% of PSU as simply plug and play.  More "might" work or might be very frustrating to end users, or might destroy the PSU or in the case of junk PSU might cause an electrical fire.

Doesn't seem much value in going beyond the ATX power spec given how power efficient FPGAs are.

Sorry, you're just plain wrong.

For the ease of explanation and without loss of generality let's assume our PSU is a single rail, non-modular device.
All the wires are soldered at the same place of the PCB.
Ever seen an open PSU, DAT? A whole bunch of 12V wires are soldered in one place, usually using very generous amounts of solder to improve the wire-to-wire electrical interface.
The same goes for ground wires - they all end up at the same spot.
The PSU circuitry doesn't know or care whether it delivers 375W across two PEG connectors and a bunch of molex 4 pin peripheral connectors or just one connector.
The PSU was built for one assumption only: to deliver 100% of the rated power as cleanly as possible - this is a prerequisite for receiving the 80 PLUS certification.

While it is true that the wires themselves have their rated amperage it is much higher than the rating of any commonly used connector and could only pose a problem if the manufacturer used substandard cabling. The spec recommends 18 AWG as the minimum wire gauge and only crappy low-end, low-power units are equipped with 20 AWG wiring when the manufacturer needs to cut corners.

The situation gets slightly more complicated when a multi-rail device is used: you need to know the shutoff threshold for the virtual rail you're drawing power from.

A modular PSU includes an additional potential point of failure - the modular board and connectors.
These are most often the same Mini-Fit Jr, HCS variety as the PEG-6 connector so no problem here.
Should the manufacturer go with some non-standard design, it's up to the user to parse the relevant specs and verify how much power the connectors can deliver.

Speaking of wires, this is never a good sign:
https://i.imgur.com/GRlkY.jpg
Each PEG connector should come with its own wire to prevent overloading the PEG connector closest to the PSU.
This is another sign of a manufacturer going cheap.

If I had a PSU like this one and had to push the PEG connectors hard, I'd disassemble the PEG connector and apply solder to the place where both wires are crimped to the contact in order to minimize resistance.

Not true at all.  All PSU have current limitations for safety.  They wouldn't be UL compliant if they didn't.

So while the PSU could deliver 1200W on a single giant cable it won't.  When current on one connector exceeds the current limit it will trip.  This has been verified multiple times by many different sources when testing PSU.

Here is just one example:
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story3&reid=273

A single 1200W rail but it trips if excessive current occurs on a single connector.

Call it "Virtual rail" or "safety current limit" but you try to pull more than the PSU was designed to push on 1 wire and it will trip.  

Once again given that 150W is more than enough to power 16 FPGA (>3 GH/s) on a giant 2 foot board w/ 14 backplane slots and $2000 in FPGA (and more than enough for anything less) why make it complicated?  
Why would you need more current?  
Why take risk that it will be incompatible w/ PSU "current protection" limitations?
If you honestly needed to make a backplane which powered 30 FPGAs (>6 GH/s) would adding second PCIe connector by that much a "hassle"?


Could you get away with exceeding the spec?  Probably.  Would it work with 100% of the PSU?  No it wouldn't work in this very highly rated PSU in the link above.  As you pointed out in your PSU putting 2 PCIe connectors on one set of wires leads to more potential confusion to the end user.  If board is pulling 300W from a single connector and the user plugs two boards into 2 connectors on the same set of wires the PSU will trip unless its current protection allows 50A+ on a set of wires.

More confusion, more complications.  Simply put one PCIe 6 pin connector for each 150W you need and it is universally compatible with 100% of PSU on the market without hacking or "gotchas".  Given a 1200W PSU could power 6 boards each >3GH/s it is hardly a "limitation" to follow the spec.

DAT, please... take a deep breath, re-read the spec, and ponder on it for a while.

Current version of the ATX spec abolished the 20 amps per rail limitation.
The 20A per wire limitation still stands but it's so much higher than the 13A Mini-Fit Jr per-contact limitation that it's pretty much moot - we can't violate this limitation without burning the connector first.
This 20A per wire limit is not enforced on hardware level.

A single-rail PSU does not measure the load at any individual DC output, only total OCP (over current protection) is hopefully active (BTW, I never advocated crossing the global OCP).
That's precisely the difference between single rail and multi rail devices: a multi-rail PSU measures load levels at each configured virtual rail.
I said that in the case of a multi rail PSU you need to take the per-rail OCP limit levels into consideration.

I don't like repeating myself but let's look at what I disagreed with you about:

You said that a PEG-6/8 connector is only good for 75/150 watts (6.25/12.5 amps).
Using ATX spec and manufacturer data I proved that neither the wires themselves nor the connectors are limited to such low amperage.
With three 12V wires, the PEG-6 connector is in ATX spec until 60A wire-wise.
The connector contacts max out at 13A thus limit the connector to 39A (468W). I suggested a safer value of 375W as the one to go with.
A multi-rail PSU might impose a current limit on the rail, e.g. 25A (300W) but a single-rail device cannot.
Here (http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story5&reid=217) are a few (http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story4&reid=274) examples (http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story4&reid=266) of how single rail PSUs are wired up internally - take a glance at the PCB pictures, see how the wires are soldered in together.  If you ever took a class in electronics and circuits or electrical engineering the PCB picture should tell you a lot.

I know you're an expert in software and not in hardware but that's really all there is to single rail PSUs. Not exactly rocket science.
A single-rail unit cannot shut off because one of the connectors is overloaded as long as it's not overloaded high enough to trip the global OCP limit.

The ATX spec limits the PCIe devices, not connectors. Re-read it if you don't believe me.
That's the only thing I disagreed with you about.

TL;DR
There's no hacking involved nor "gotchas".
When using a multi-rail unit, you need to be aware of the individual per-rail OCP limits.

In a single-rail device the only limit you need to worry about is global load - a sum of all DC outputs.
A connector consists of wires (the spec mandates 20A per wire limitation but no PSU actually checks that) and contacts (the Mini-Fit Jr HCS are rated at 13A each).
The ATX spec limitation of 75W/150W applies to devices, not to connectors.
Electrically, the PEG-6 connector is capable of 468W. I suggested 80% of that value as a safer load.

Damn it, it is a QUAD rail PSU you're linking to.
Four 12V rails with their individual OCP limits to worry about instead of one!

Look at the load table:
[  3.3V  |  5V  |  12V1  |  12V2  |  12V3  |  12V4  ]
[  25A   |  25A |  30A   |  30A    |  45A   |   45A   ]

Try actually reading the site you're linking to:
The "Easy Rail" is just meaningless marketroid blabbering with no real life implications.
XFX used to use this keyword to indicate single-rail devices but apparently every PSU they make is now advertized as Easy Rail, no matter the number of rails.

You imply that delivering more than 75 watts through the PEG-6 connector is in violation of the spec.
For the n-th time, the spec regulates the GPU, not the connectors.
For reasons already stated, the PEG-6 connector is electrically capable of delivering over 400W and it will do so unless the rail it's feeding from has a lower OCP limit.

As to the merit of the whole discussion, let's assume we're using BFL FPGA devices each drawing 90W.
You imply that a single PEG-6 connector could at most power one such device and would be overloaded doing so (75W vs 90W).

I have shown that the PEG-6 connector can safely run three BFL FPGAs, each of them feeding off its own 12V wire (there are three of those).
All that without "hacking" or "gotchas" you accused me of, all in-spec.

With some additional work (merging the three 12V wires' output together and feeding the FPGAs from that) the same PEG-6 connector can safely power four BFL FPGAs without getting close to manufacturers' ratings for the wires or contacts.

EXACTLY.  THAT WAS MY ENTIRE DAMN POINT.  If you draw only 150W from a PCIE connector then you are GUARANTEED UNIVERSAL COMPATIBILITY with all existing PSU.  If you draw more well it may or may not work.


Well we aren't talking about BFL.  We are talking about Spartan however if you are going to derail threads and debate how about you STOP PUTTING WORDS IN MY MOUTH.  I never said 75W I said 150W.  150W DC can drive 2x BFL FPGA.

Can you draw more?  Sure and it may not work with all PSU.  You may cause OCP trips, or you may overload the PSU.   Given the # of PCIe connectors directly scales to the # wattage of the device I see it as a non-issue.

150W = universal compatibility.
A unit w/ 4 PCIe connectors lets you draw 600W
A unit w/ 6 PCIe connectors lets you draw 900W
A unit w/ 8 PCIe connectors lets you draw 1200W

You will notice almost all 1200W PSU have .... drumroll ... 8 PCIe connectors and 900W units have ... 6 PCIe connectors.

Pushing more through a connector provides absolutely no benefit and may not work with all PSU.

If you pull 150W from a PCIe connector it is going to work w/ every single PSU.  If you pull more it is going to trip OCP on some PSU.  It will work for some and not work for others.   A lot will depend on the OCP limits, "virtual rail configuration", and how many connectors per wire (as you pointed out sometimes 2 are put on a single wire).

Given 150W is enough to power 15 Spartan-6 FPGA trying to do some >150W seems stupid.  I get you disagree.   If hypothetically someone made a board with 30 Spartan-6 I would recommend they use 2x PCIe connectors.  Wow a whole $2.30 in cost to guarantee universal compatiblity with all ATX PSU.  Seems good insurance to me.  You would say use only one even if the board uses 400W.  My recommendation would work on every single power supply on the planet, yours wouldn't.  Seems foolish to take risks going >150W when PSU MAY not be able to supply it without issue.

I get you disagree.  For highest compatitbility with ALL existing ATX PSU it simply doesn't make sense to go over 150W IMHO

I won't say anything further as we have been disrespectful and totally derailed this topic.   I won't see any responses.

read

Nice and interesting thread.

My last post in this topic, I swear.

150W is only 12.5A - no contemporary PSU has OCP limit that set low.
While it's true that 150W will always work I'd like to point out that more power will always be available.
The information how much more load the rail can handle is right there on the side of every PSU in the load table: read the amperage, divide it by 12 and voila! - you know how much power you can pull without tripping the OCP.


Please note how counterproductive sticking to 150W per PEG connector is on high-end single rail PSUs miners have heavily invested into: you'd be using less than 40% of the power available through the PEG connector.
Maximizing the number of FPGAs per PSU is very important for anyone building an FPGA farm and following my advice allows to do that cleanly, without using unnecessary cables or gadgets like molex adapters - that was my entire point.


Let me draw an analogy - 640x480 is a standard resolution any monitor in the world should be able to display.
You're saying "Stick to 640x480 and you're guaranteed universal compatibilty".
My advice is "Any contemporary device can do better than that. 640X480 is counterproductive as heck so read the manufacturer's paperwork to find the maximum safe resolution (load per a 12V rail powering the PEG connector) if you need more".

i'm not at a level to understand all the tech details.  where is this from a dev standpoint?  could someone give the schematics to a manufacturer and get a reliable product?  whats the max hashrate?

btw, my interest is for personal rigs, not commercial interests.  just wanted to be clear on that in case there were any concerns, or if commercial use of the design would violate even the spirit of the project.

The icarus is an open design. I recall seeing a BOM, not sure about the design files.

This is DIY if you had a manufacturer make this you would prob pay a extra 250 to have them put it together so it would be cheaper to just buy a foga miner already built

depends on the hashrate.  death and taxes seems to be onto a design that is very attractive.

I wouldn't say design that gives it to much credit ... maybe "concept". :)

fair enough.  your concept is very intriguing to me, and while i admit my extreme ignorance in technical proficiency to really understand, it doesn't seem like a ton of work to move from the current design, to implementing your concept.

A bitcoin fpga mining project will take at least 3 months of your life.  ;D Even with the open source RTL and SW now.

-rph

I do not understand this thread, "rph" had a project just like a circuit with four removable FPGAs and the project was almost finished, it brings back this? I see rather more cumbersome than the other.

I like this project and I would love to contribute.  I design circuit boards for an Aviation/Oilfield computer company and they allow me to use my Altium Designer Summer 09 Seat for personal projects.  PM me if you would like to chat.

nothing stopping you from starting your own project i don't think.  open source it, and everyone benefits.

make the improvements you see fit, maybe incorporating some of the expandability wishlist.  i'm looking for something that has a good ROI, that i can contract to be manufactured for my personal use.  any design i end up using, i will donate to.

...versus https://bitcointalk.org/index.php?topic=45532

http://desmond.imageshack.us/Himg577/scaled.php?server=577&filename=photo3qa.jpg&res=medium

Sincerest form of flattery?

No seriously, I'm glad to see it's catching on.  Those molex connectors are expensive, though.

If I were you I would allocate way more than 10A of power per board.  However, since you aren't soldering down the power supply to the board with the FPGA on it (like ztex and others) you can always just underpopulate the "motherboard" if you need more power per board.

I recommend using a SATA power connector instead of a 4-pin molex connector.  It's hard to find the SATA power connector without a data connector as well, but you can just leave the data side unconnected.

Good luck!

Well I see this project is the design used by btcfpga.com. What am I wondering if the complete plans for this have ever been released. I mean I see so CAD designs of the PCB boards but I cannot submit those to a company to produce them.

What I am trying to do is basically build my own FPGA boards with this design because I really like this style of miner. I am really hoping that the original poster will release the designs for his PCB boards so I can get some made. I would really love to try and build my own FPGA miner. I am willing to risk screwing up a little bit as well to learn how to build these efficiently. I know that I am asking a lot but would it be possible to get a complete parts list and the PCB board designs so I can submit them for manufacturing. I really think that I would be able to build my own boards at home.

Here is a link to a site showing you how to solider a FPGA at home.

http://www.youtube.com/watch?v=OkjOwuSEzKU

I think I could follow this man's video pretty well. I would order some stencils as well so that I could make applying the paste and everything very neatly. I mean if we could get a few of us that would like to DIY a FPGA miner to order the PCB boards together I am sure we can get a decent price. I have done research and have found companies that will make me a single PCB board at a time but it will be a premium cost. I am trying to get the cost as low as possible.

If I could get the Spartan 6 chips for about $150 each I would like to think that I could build a complete unit for around $700.00 which would be saving me like $400 dollars from the units that can be purchased at BTCFPGA.com.

Like I said I simply would like to be able to build my own FPGA miner for a fun hobby/project. I would not be reselling them in anyway. They would be for personal use only. I am hoping the original poster will release the designs to me. I would be willing to pay a little bit for the designs privately if that was possible. Original poster please just PM with the cost details for the PCB board design ready to send to the manufacturer and a complete parts list.

I'd also like to make my own. But seems these DIY threads tend to dry up as quickly as they start.

The schematics were taken down awhile ago
The designs were taken down awhile ago... I prototyped this board and had some bugs with it and have worked them out in future revisions. I don't think you realize how much more this stuff costs in low quantity..... you wouldn't be able to make these for $700 a unit in low quantity.... you would need to make over 100 to get to around $700..... for example say you wanted to make 3 units the parts for each backplane would be around $80 -$90 + the price of the PCB's which would be around $180 for 5 then you need 12 spartan 6 plugin boards the parts for those would be around $185-$205 depending on what speed grade of FPGA you get each plus you would need 12 4layer PCB's which are pretty expensive in low qty if you got 12 of them made it would be around $400-$450. So now lets add this all up....

Parts for backplane: $85 ea * 3 =                                  $255
PCBs for backplane 5 for                                               $180
Parts for Spartan 6 plugin board = $185 ea * 12 =             $2220
PCBs for 12 Spartan 6 plugin board =                               $400
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                                                    TOTAL:  $3055
                                                        PRICE PER UNIT:  $1018.33

Oh and it will be more than that you have to include other things you'll need such as  taxes on the parts, shipping, solder, soldering wick, flux, a good soldering Iron, and more....... The key to getting it cheap is QTY!

I may be able to make a kit or something..... actually the original plan was to just sell kits but I figured most people wouldn't be able to or wouldn't want to solder the 484 ball BGA and all the tiny 0402 capacitors and resistors + the ARM chip that only has 0.008 in. between pins..... I would be happy to make a kit though as long as there is enough interest.

I think there is interest. It's scattered, but they will come. You could even initially create a thread to sell the full blown, non-buggy(!) design and initially sell the design plans. And thereafter, if you wanted to compile and sell a kits, you could probably do that too. See my thread linked below, and you can see that it started to generate interest from the start. But it fizzled soon after, maybe because people realized it was best if was backed by someone with FPGA circuitry know-how.

https://bitcointalk.org/index.php?topic=78935.0

On top of all that, you can get feedback from us and we can together streamline the process to reduce costs even more. Six sigma!  :D

One example I can think of, but admittedly just speculating on, would be to consider if the traces on the PCB could be made to act as caps near the FPGA (cost savings built into the design). I'm not sure if it would work, since the capacitance value might be greater than a thick PCB dialectric would allow practically. A capacitance measurement on parallel traces could test this idea. [late entry: I just saw that the capacitors are super cheap, so this would not be a significant cost savings at all, but if it was easy enough to design into the PCB, it could at least save the time to solder them into the circuit]

I have 10 BTC waiting to barter for a complete non-buggy DIY design.

Hey man,

I would hope there would be interest in DIY kits. I mean if I understand what you are offering correctly I think that would be a great idea. I understood it as you would basically put all the parts together and send them in a kit correct? I know it would not be soildered but I think that would be a great idea. Maybe you could make a new post to gauge interest in a project like that. I would prefer a design similar to the one that you had designed. Something that could be added onto when more cash is acquired.

Now would you offer these kits at a lower price if there was enough interest? Let's say 100 kit orders were placed, would you be able to offer it at lets say $500 for the starter back plane, all the chips, and the PCB board? Now I know that you would only be able to include 2-3 FPGA chips at that price but I am looking for an option that allows me to start small and work my way up. I really love the design of the miner you designed for btcfpga.com. I would like to see maybe an 8x or 16x back-plane as well that way I could only buy single daughter board kits for lets say around $150-$175 bucks.

I would like to hear some of the ideas you have concerning a DIY project kit. I mean theoretically if you ordered enough FPGA chips at once I am sure you can get the cost down as well as the PCB back planes and daughter boards. Just would love to your ideas on a kit and the cost factor. If it is something that could compete with the ButterFly Labs single I think there would be a hell of a lot more people buying these kits. I mean I would like to pay around $600 bucks for a complete 4x FPGA setup. Also I think you should include a stencil for the FPGA soldering so that newbies could attempt this with some research. I would hope that they would have enough sense to practice before using the actual chip but that would be on them and not you.

Errr I don't think you realize there is no price discount on the FPGAs even in large QTY.... see for yourself Digikey and Avnet are the only authorized distributors of Xilinx chips...

http://search.digikey.com/us/en/products/XC6SLX150-2FGG484C/122-1750-ND/2339792

http://search.digikey.com/us/en/products/XC6SLX150-3FGG484C/122-1725-ND/2339800

http://avnetexpress.avnet.com/store/em/EMController/FPGA/Xilinx/XC6SLX150-2FGG484C/_/R-12249118/A-12249118/An-0?action=part&catalogId=500201&langId=-1&storeId=500201&listIndex=-1

http://avnetexpress.avnet.com/store/em/EMController/FPGA/Xilinx/XC6SLX150-3FGG484C/_/R-12261582/A-12261582/An-0?action=part&catalogId=500201&langId=-1&storeId=500201&listIndex=-1


The only other options are figuring out how to get the chips directly from Xilinx and if I can get price discounts like that I figure there would be a min qty ordering them like that though. Say they required you to buy at least 1000 chips to get the chips straight from them I don't have over $100k to drop on FPGAs so I can get them at discount. This is just a example but I will look into it and see if this is possible.

The other option is finding some asian unauthorized dealer that could easily send you fake / old chips that have been remarked to look like the chips you ordered, used chips, broken chips, or just straight rip you off on thousands of dollars worth of chips and not send anything and there wouldn't be anything you could do about it.


Anyway what I was planning was maybe making some kits that would include all the parts to make the backplane and daughter boards + the PCBs idk if I would include the FPGAs in with this or not and I'm not sure what the pricing would be yet but definitely cheaper than buying it already soldered and cheaper than buying the parts yourself in low qty. I might make the kits separate also like a backplane kit and the daughter board kit.

 Oh and a stencil isnt needed the FPGAs come with the solder balls already attached you just have to put a very thin layer of flux on the pcb and get the FPGA perfectly aligned on there and heat it up with your preferred DIY BGA soldering method(toaster oven, skillet, hot air gun, or whatever you can think up that will do the job =p) following Xilinx's soldering guidelines for the Spartan 6 as closely as possible to make the solder balls bond to the PCB.

I cant seem to find the link to the schematics, anyone?

Hey,

That would be fine for me if the FPGA chip was not included. I would just really like the kit to include the daughter boards and back-plane and parts needed to construct the miner. What would be the cost of the kit without the FPGA chip? I would be interested in something like that for sure if it was cheap enough.

Same here. I'd buy a kit without an FPGA. But would hope the design is proven not buggy. Also, would need direction on how to proceed with loading FPGA.

I don't think this is feasible. The FPGA is actually the part that is most tricky to solder onto such a board (and easiest to mess up), so it seems backward to me to ship kits without FPGAs.

Yeah now that I think about it I would probably include the FPGAs but there would be no price discount on them. A kit like this isnt meant for someone with no experience doing surface mount soldering. Someone who has experience doing BGA reworks and repairs would have no problem soldering these FPGAs. I don't see any problem in allowing people to get discounted boards by assembling them themselves. Of course we would put a big disclaimer warning people that soldering these small parts and BGAs is not easy and should be done by someone with experience and we offer no warranty at all on the kits.

Hey,

Ya either way I would be cool with it. Maybe you should post a thread about kits with prices. I completly understand not offering any warrenty. There should not be one at all personally. It should be done at the users own risk. Basically what kind of prices are we talking. I would like to see a 8X or 12X back plane in the kit so that I could get 1.6 to 2.4 GH/S. Let me know what you are thinking./

I lost any interest in DIY FPGA's for this reason:

https://bitcointalk.org/index.php?topic=83985.0

http://www.butterflylabs.com/bitforce-sc-faq/