Overall the results from using the Ebay scrap were positive

The boards are a little long making programming via JTAG difficult, not to mention the 14 Pin IDC connector is not really suitable for a standard 14 pin IDC plug (a fact I discovered AFTER I returned from China with a bag full of parts).

As we can see it is a little cramped by the JTAG connector (directly inline with a fan), yep I can say officially that even a 12 Volt fan is capable of doing serious damage to finger tips and finger nails.

Caveats

There were a number of issues with the FORA(For-a) video processing boards.

Yep We had an Idea that there was something shitty about het power-supply setup…
The Bellinix modules used are ‘programmable’ via an external sense resistor, problem was that when we replaced the sense resistor NOTHING happened to the supply voltage, in fact completely removing the sense resistor also had no effect.
This indicates that the Belinix modules are ‘non-standard’ even though they are marked as standard parts (you just gotta love the way japs do business)
So to modify the FPGA core voltage you would have to reverse engineer the Belinix DC/DC modules to find out what they had done to them, or alternatively throw them away and replace with standard product.

After finally getting the power supply of the existing miner back on line, we found that the FOR-A
experimental cards had gone dead.
In fact Two FOR-A cards had gone dead.

Both cards have exactly the SAME fault the 3V3 rail is shorted to the majority of the 5V line
It looks like the Shitty Japanese PSU design is back with a vengeance (and everything was working beautifully together).

Since both a modified and un-modified card went defective, it seems logical that there is some sort of underlying PSU design fault in the FOR.A product.

We will need to spend a bit of time resolving this.

Ok 1 hour later……
SURPRISE!!!,The root cause is the USB cable…. (yep for all those people throwing hubs and cables randomly at their computer in an attempt to maximize the connections)

So how does a USB cable take down a PSU

If you take a look at the way a USB plug /socet is constructed, the external shield wraps ROUND the plug, but because like everything else it is made from the cheapest crap metal available.
The wrapping process leaves a visible & physical break in one side of the plug.
now here is the pinch……

IF the join is on the BACK of teh plug BEHIND the white insulator holding teh connections, then there is no problem
but IF the join is in the FRONT directly inline with the connections, this allows the join to move releasing pressure on the parts that hold the USB connection together.

Now since USB was NEVER designed to operate with a direct face to face connect/disconnect (take a look at a USB connection they are staggered so as they make contact in a certain sequence), this causes the USB devices to flip in & out of connection and in doing so , it reverse bias some of the hubs leading to a direct short of power into the connected RS232 devices.

So the motto of the story is…. Don’t go building massive trees of USB devices., all it takes is one shitty cable design too give you a bad day.

Yep…..
There we are going full swing building another new mining rig, only to getup this morning to find one of the old bitcoin rigs has gone tits up……

Thanks again to “XILENCE” and their shitty ATX PSU’s.
Last time I had problems I decided to split out the rigs and dual supply the FPGA’s to avoid any problems.

Unfortunately it looks like it was not enough, pulling 230W out of their 500W PSU for 24/7 was just too much..
China quality has once again shown its true colours.

Looks like their “Auto fan controller” did not work, so they just tied the fan to the 5v line, hay at least they could ship the goods…. unfortunately it did not allow enough airflow to be moved when things warmed up a little.

Finally I would just like to put a call out to this company:
Enhance Technology Ltd.進階科技有限公司
Address: Flat D, 19/F., block 3, Golden Dragon ind. Centre,172-180 Tai Lin Pai Rd.,
Kwai Chung, Hong Kong
Tel:(852) 2386 3797 Fax:(852) 2386-6152 E-mail : sales@enhance.com.hk

Who in my opinion are really are a dishonest company.

First They sold 3R system PSU supplies that were rated at 30A, but when inspected internally the parts were only for 12A

Second The did NOTHING: Would not reply to my complaints UNTIL I involved the Hong Kong consumer council, then magically they want to resolve it straight away.
Then all of a sudden they are interested to rectify my problems.

Thirdly
They ‘offered’ to ensure I was very happy.
Forthly
They sent me ‘replacement goods’ for the BRAND NEW defective 3R SYSTEM PSU… unfortunately the replacement goods were some shit that had already seen significant usage, and about the same spec as the 3R Systems product.

So I would advise you to STAY AWAY from ANYTHING

Related to either:
3R SYSTEM or
Enhance Technology Ltd.進階科技有限公司

Ok….
A couple of days ago I posted a screen shot of the Ebay Scrap miner pushing 120MH/s

Today I have a screen shot at 150MH/s

















All screenshots are taken after a reset job against the miner, so as the true rate can be seen
And each miner has produced 0% Invalids within the last 24 hours.
An “invalid” is when the FPGA hits an internal bit flip, producing a hash which it claims is valid but when checked is actually a bad hash.
Generally “invalids” are a good sign that something is not right with the FPGA/PSU or HDL bit file.
A good way to produce lots of invalids is to over-clock the FPGA or take it beyond a safe core temperature.

FOR-A bitminer (formally Ebay scrap job 11)
Since this board range has been modified into a viable miner, it has been given a formal name.

FOR-A Bitminer

The required RS232 connections are as follows:
0V
RX
TX
Please keep in mind that these connections are tied into the FPGA relative to about 2.5v-3.3v
Therefore you MUST implement an FTDI level convertor FT232RL is fine.
By purchasing the correct breakout boards, the I/O can be configured at 3V3 5V0 or with the use of the VIO pin on the FTDI device , you can configure non-standard voltages.

The markings in the photograph are relative to the FPGA so TX is TX OUT, RX is RX in.
When connecting to the FTDI chip you make the connection:
TX(FPGA) to RX(FTDI)
RX(FPGA) to TX(FTDI)

Poor product design
As pointed out in part one, FOR-A product design is poor on a number of levels.

First Issue, they do not bring all the FPGA pins through the PCB, instead terminating some on the top layer others are terminated halfway through the board, but everything that appears on the underside of the PCB is in use and also offset strangely.
Possibly done to confuse reverse-engineer probes (it might also be the reason for their abysmal attempt at disabling the JTAG with EXTERNAL logic!!!)

Failure to bring all the FPGA pads through the board means that any re-flow profile will be completely to cock…., because many of the pins are trapped under the FPGA, but do not appear on the bottom layer, so cannot get enough heat to re-flow correctly….
Then we have the ‘stupidity’ of massive ground planes on the bottom of the P.C.B COVERING the FPGA pins on earlier levels..

this results in you having to use an unsuitable re-flow profile to get the bloody FPGA to solder.. which in turn weakens the other pins that DO come through the board.

**(If any one has actually taken a VIRTEX FPGA apart… (mee.meee.meee), you will see something very strange, the metal ‘top’ is actually a massive airspace, with a very small chip area bang in the centre of this top, in effect the ONLY way to transfer heat from the top cap is through the die area of the FPGA.
so if you need to solder the BGA pins without heat from the bottom you need to get the FPGA up-to about 400 Deg.c… for 8 minutes.

Then there is the issue related to PCB flex and only soldering the FPGA to the top layer… since the pin pads have a massive FPGA to hold in place, they pads pull out of the top layer!!!.

Ultimately we had to sacrifice a PCB to discover the FPGA connections.

Power supply design
In this area, a simple WTF will suffice……
They use BOTH the PCI Express 12V & 3V3, they then take the 12V and regulate it down to 5V(+-3%), then use a TDK 5v to 5v regulator for accuracy!!! this feeds various other DC/DC convertors.. all very expensive Japanese kit. (Japanese love to promote their own industries at the customers cost)

The 3V3 is then badly regulated(+-3%) to 1V5 and fed to further DC/DC regulators.

The whole thing is then strung together like a set of christmas tree lights with various systems to ‘prevent’ incorrect power-up.

With a reasonable amount of stupidity thrown in…..
I.E If you turn off the 3V3 line then the board powers down (correctly) to protect various aspects of the circuit.
BUT….. if you DISCONNECT the 3V3 to simulate an open condition, then 90% of the board powers up and then attempts to burn out various DC/DC section and other components…
You can hear the DC/DC convertors whining and in some cases the ceramic caps physically breaking over!!!
(next time guys connect a pulldown/pull up to the 3V3 line to cover this floating situation!!!)
Also DUMP your current PSU design , go Texas Instruments & MAXIM and save 50% of the cost…

So it is within this complete abortion of a power supply system that we will attempt to combine all the input voltage connections to be 12V.
Really we should just pull off the whole 12v DC/DC shit and run 5V DC into the supplies, but removing the DC/DC bricks is going to be too difficult for most people.

Combining the Power Supplies

First note:
The PCB WILL NOT be suitable for insertion into a PCI slot after this modification….,but we will ensure the mod can be ‘backed out’ if needed.

The Two main DC/DC convertors we are interested in are the Bellnix BST04 (3V3) and the BST12(5V5)
After checking the spec sheets we can see that the BST04 can be safely driven from 5V5 (you can see where we are going with this!!)

We see that pin 2 is the input voltage and pin 5 is the output regulated supply.

First off we check to ensure that the PCI 3V3 is ONLY connected to the BST04,
next job is to link the BST12 output to the BST04 input, effectively eradicating ALL the 3V3 supply and driving it off the 12V.

The 12V BST12 is ‘rated’ at 16A which would give us 6A for each FPGA with 2A for the other DC/DC convertors and 2A headroom…
Currently the BST12 consumes 1A4 and the BST04 5A5 when the PCB is configured with firmware.

Well……
The time has finally come to Build our bitcoin miner.

Specification

• Ebay Scrap FPGA
• Cost <$100USD
• Speed >150MH/s
• UART Interface
• Standard ATX computer Power supply

A journey of a thousand li begins with a single step
One of the more difficult aspects of using Ebay FPGA scrap is actually selecting suitable donor equipment or suitable donar PCBs.

Key points to identify

• FPGA Type
• Powered/Unpowered
• Guesstimate at approximate integral power supply capability
• Possible points of connection

FPGA Type
There is absolutely no point on going onto Ebay and getting 400 Spartan 3A’s cheap..
Because the time taken to wire up just 10 FPGA boards has the potential to make you go insane.

Aim for a minimum device specification of:

• Virtex 5 110T
• Spartan 6 150

Any FPGA above these devices is a bonus..
Because at-least you can fit a fully unrolled Bit-coin design. Don’t go for anything smaller than the above devices becasue the amount of hashing power available  would make ROI far too long, especially in the current Bit-coin environment .
Remember, the bit-coin difficulty is changing at least +10% every 10 days.

Powered/Unpowered board
Many of the FPGA boards on Ebay are basically ‘scrap’, but there are different types of scrap.

Some of the ‘scrap’ is just an FPGA with a bit of PCB left around it where it was cut from a larger board, You may fantasize that you are going to buy this item, design & build a PCB, build & design a PSU ,re-ball the device, solder it , then write  HDL code to run the device..

Or you can just buy a PCB that contains the  device with  DC/DC brick convertors on already and do a bit of reverse engineering work.

The difference is, that using the latter method, you know at some time in the past the  board worked reliably, plus the power circuitry has been designed by experts and usually implemented on a 16 layer PCB which means the heat is just going to be sucked clean out of the FPGA making your hack all the more stable.
(many Ebay sellers are selling items that actually work anyway…)

Enough Already… tell me the source
Ok
You want this product:

http://www.ebay.com/itm/380632461849?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Yes I know it says it is sold, but it has since been re-listed.
The price should be about $90USD Each PCB, for that you get TWO FPGA’s and DC/DC power supplies to run the devices.

Don’t worry about the PCI connector, we will be re-engineering the board with ONLY 5 connections!!.

• 12V
• 3V3
• 0v (GND)
• RS232 RX
• RS232 TX

The FPGA source for bit-coin on Xilinx devices is already available online via github, but I will be linking to a pre-compiled BIT file.

List of required parts

• Fora E03251-2 board
• JTAG cable
• RS232 Board
• ATX power supply
• 2-3 Maglev Sunon 12v fans (ME50151V1-0000-A99)
• 2 Heatsinks(36mm*36mm*25mm)

How do I know it will work?
Because I already have one working reliably for a couple of days.

Breakdown of forthcoming  tasks

• Outline connections for UART (not a big job… two/three soldered wires)
• Look at getting the supply to just 12v (I’ve had difficult times with 3V3 supplies)
• Possible increase in speed, This depends on the DC/DC convertors.

Unfortunately, FOR-A did a piss poor job of designing the power supplies as well as the FPGA Layout.
I have ‘heard’ some of the Ceramic caps breaking over on the memory & infrastructure areas of the PCB.
Hopefully we can strip these out, since they should not be needed for the FPGAs and as long as we tri-state the related FPGA pins the current consumption should be lower.

Just a Tip (FOR-A) guys… when you design with an FPGA bring ALL the pads through the board with VIAS, because the way you have done it leads to a number of serious issues related to product reliability….

I’m planning to do an article on how to convert Ebay scrap FPGA into bitcoin miners.

Target cost is going to be about $100USD per 200MH/s (cost mostly on the ebay scrap)
so in the case of this…

4 FPA rig..

It would only cost you $400usd!!!!!

Now obviously it is not going to have the same ‘expert’ polish as this top of the line product.. but what do you want for 400 bucks..

Yep I know ASICS are coming soon and that Avalon is already on the market.
This is not a ‘get-rich’ quick scheme
Rather it is a last ditch attempt for people to have a final dabble in bitcoin, before the shit hits the fan and mining becomes impossible for most ‘normal’ people.
Who knows this shit may even sell for $250,000USD in 30 years just like the Apple 1

Litecoin… well lets see what is possible….., but from early experiments it is not cost effective even at $100Us because the KH/s rate is way too low

So if anyone is interested post a comment, maybe even check out the advertisers.

The coins?
Well everyone else does it so I can too…….

So today I went out and purchased a couple of Xilence PSU (XP500), specifically because they were rated at 30.0A at 3V3.

We needed a fairly strong 3V3 supply rail to feed a couple of maxim buck converters down to 0.98v for an FPGA project.

You would think that 3V3@30A would be able to handle such a simple situation.

Well you would be dead wrong..
After loading the PSU upto 6A the supply rail dropped to 3v1 we then added another 6A load and the rail hit 2V98 Also the 12V rail began to sag down to 11v8 volts and the 5V rail hit 4V8, even with no loading applied to anything other than the 3V3 rail.

Considering these supplies are rated at 3V3@30A, we should not see such poor power degradation with what is basically a 12A loading on the 3V3 rail.

By the time we were at 18A@3v3 the 3v3 rail was below 2v9 and the 12V rail was also in decline.

Furthermore the power supply started to make a sound as if there was a screw loose in the cooling fan, removal of the load caused the sound to disappear.
I’m of the mind that something was breaking down inside the PSU whenever the 3V3 supply was loaded.

OK fine let us contact their support…
After finally getting their support system to accept the email request and supplying the PSU serial number
I STILL have NOT had a reply after 7 Days….

Is the quality of the Xilence PSU bad or is the application unsuitable?
Well, to put this in perspective, I also purchased a really shitty Chinese made ATX-320T PSU that claims it can supply 3v3@14A, this thing cost less than $11USD(I kid you not)
After 4 months at an overload of 18A@3v3 the supply rail on the Chinese PSU has dipped down to 3V2 the 12V rail is at 12V2 and the thing is still as quiet as a whisper, plus no magic blue smoke daemon has appeared.

Recommendation
Do not EVER buy Xilence PSU’s, it may even be better to purchase that shittly little Chinese brand after all.

Conclusion
Xilence PSU’s appear to suck ass so badly that you would NOT want one inside your computer.
By the way their internal build quality on the PSU is basically ‘Fucking abysmal’, parts of the inline filter are ‘flapping about’ in the air as if it was an afterthought needed to pass the EMI standards.
Whilst there may be many Xilence the market, such poor power regulation can only lead to seriously stressed computer parts and early failure of equipment.

Time to return this Xilence crap to the shop and save some serious money.

Since the ASIC order went tits up at Tom’s ASIC fuckfest and BFL STILL have not delivered product, we spent the time working on our existing FPGA miner.

Improved in every way
Xilinx development boards are actually very good and it is a testament to the design of the Power-supplies that we managed to push the Bitcoin mining design to 200MH/s ,But why was the board consuming 47W when hashing hit 200MH/s?

The secondary issue was why the logic would not go faster than 200MH/s, even with improved FIFO & UART communication routines, try as we might I would not work, I had pushed the same FPGA to 250MHZ for another project, so it was unlikely to be clock related.

A new Beginning
It now seems that all these issues have now been solved after designing a completely new Power supply with improved layout (we also added two MASSIVE power planes which also act as a heat sink).

The FPGA design is now consuming 10W-15W per board and we have pushed the core to 370MH/s… yep a single core doing 370Mh/s….

So where is the power going?
0v95 Supply is sitting at about 6-7 Amps!!!
3v3 Supply is consuming about 1 amp, but that can be reduced since we have about 16 diagnostic LED’s strung off the IOAUX power line.
We may need to try and parallel up a couple of the 0v95 supplies in an attempt to cool the switching FETS down, we could just change the Capacitor/Inductor fet configuration, but that can be a real pain to get working efficiently, far easier to just parallel up a couple of supplies.

What is the point with ASICS being released soon?
Well:

Litecoin?
Yep in good old hacker style, we may have discovered a weakness in the Litecoin system that would allow us to mine without consuming massive amounts of ram.
We say ‘might’ because we have only looked at the system very superficially, but if we are correct then with a minor performance hit we could limit down the ram size.

We have recently re-gained control of this site, back from an admin-user.
This person was given the ability to post as the admin of the site.
A number of forums related to bit-coin (https://bitcointalk.org) have been linked here, these links will remain as will the research.

Unfortunately, the person involved is still causing mischief on some sites, mainly by reusing certain monikers and requiring payment for the release of them.
We attempted to re-route the ownership of the accounts via email, but failed.
The person in question has also been issued a cease and desist letter from our solicitors.

To make matters more complex these monikers have been in use for several years on other non bit-coin sites and since the SEO connected to these monikers has some value they have also been appearing in Eastern-Europe.

For the record, most of the technical analysis posted on various bit-coin forums (https://bitcointalk.org) is not under the ownership of the person using the moniker, but rather from a secondary source and then re-worded.
The plan was to build SEO links of ‘intelligent and useful material’ related to various aspects of bit-coin.

As regards the email address:
har***re@hardcoreforensics.com, this is now under control of a different admin.

Site owner.

As is the way, we were sidetracked into taking a look at getting WiFi working on the Samsung 2440 embedded control board, the idea being that we could have a backup system for when:
1.HongKong telecom manage to cut the telephone lines.
2.The shitty little HKT ADSL modem or its PSU burst into flames again, yep it only takes them 3 DAYS to get a replacement to you.
3.Dock with my mobile phone, since that has unlimited data rate, which means I can cut one ADSL & one router from the mix I am currently using.

Sadly getting WIFI working on an embedded board is not that easy, EVEN with linux

Tried downloading ‘compat-wireless-2012-12-17′, but unfortunately the integral bash scripts wont run under busy box on the embedded system.

Tried downloading Bash for the embedded system, but it won’t compile, instead giving a segmentation error.

Tried cross compiling the needed wireless libraries… fail……

It’s not that I cannot figure it out, but rather how much is my time worth to get WIFO working on what is basically a dead out of date underpowered board.

Solution

http://www.hardkernel.com/renewal_2011/products/prdt_info.php

For $89USD+$30USD shipping we can get an up-to-date Quad core samsung4412 at-least 4 times faster than a Pi and with enough memory to run a miner controller for a good many ASIC miner units and it comes with a functioning wireless installation of linux.