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41  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 20, 2013, 07:45:04 AM
The on-board 0.8V, 30A regulator would add about $15-$20 to the design. For 10-15 cards, the money saved would buy a good PSU with voltage trim option.

Either way, the cards work fine if the voltage isn't perfectly regulated. They just run a bit cooler under 12V, and a bit faster/hotter over 12V.
42  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 20, 2013, 06:31:03 AM
i'm still not sure if my concern was fully answered; what makes this board design work when the H-board string design ended in molten plastic and scorched PCB?
We have a better design Smiley
43  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 19, 2013, 08:54:11 PM
That will change. The chips are going down to $5/chip.

Either they will go to $5/chip and lower, or they will not be sold at all. In the first case, you need a cheap, low-overhead, mining board. In the second case, you don't need a mining board at all.
44  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 19, 2013, 08:45:29 PM
So far, we have no indication of increased failure rate. The prototypes that we have are rock solid with constant temperature and constant hashing speed. In a couple of weeks, we'll make a few dozen more boards, and we'll see what happens to the failure rate.
45  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 19, 2013, 07:55:39 PM
These boards don't have additional electronics. On the contrary, a lot of the expensive components have been removed, and the 2-layer board is cheaper too.
46  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 19, 2013, 07:45:40 PM
And it's not just the cost of the components, but also the availability of some of the more exotic ones.

Another factor is the circuit board design. The fast switching DC/DC regulators typically require at least a 4-layer board for good performance. The One String design uses a cheap 2-layer board.
47  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 19, 2013, 07:26:42 PM
Oh, so the cost savings is in the parts list, not the actual power supply.

Correct. You still need a 12V power supply. Each card draws about 2-2.5 Amps, depending on the exact voltage.
48  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 19, 2013, 07:23:43 PM
But this design has a very big disadvantage. If the first chip in the series connection got damaged the other chips doesnt work anymore, too.

That depends on the exact nature of the damage. If the hashing core is damaged (which makes up the biggest part of the chip), the chip may still provide a working connection to the other chips.

It's not much different than low-voltage bitfury designs, such as the H-CARD. In those designs the communication between the chips also forms a chain. Actually, the M-BOARD has 4 H-CARDS with total of 64 chips in each chain.
49  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 19, 2013, 07:06:54 PM
This design uses 12V to power the chips directly. Other designs, such as the H-CARD have an on-board 12V -> 0.8V power regulator with 30-50Amp capability.

In both cases, you need a 12V supply, but for our new board, you avoid the additional cost of the 0.8V regulator. Also, the 0.8V regulator is typically only about 90% efficient, so it creates 10% more heat for the same hashrate. The powerful switching regulator also produces lots of electrical interference that can degrade reliability of the overall system, and requires additional components (capacitors/inductors) to help reduce the noise.
50  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 17, 2013, 03:53:21 AM
I don't think Avalon chips have a String feature.
51  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 16, 2013, 07:29:28 AM
A tiny NXP ARM, LPC11U24FHI33/301.

Note that the design is not dependent on the exact type of microcontroller. As long as it has a built-in USB interface, some I/O pins, and a few kB of RAM, it can be used in the design. We picked the LPC because we had already used it on the bi*fury.
52  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 16, 2013, 06:30:43 AM
Very nice. Are you using your own custom miner software?
The USB interface protocol is the same as for bi*fury, so the latest cgminer/bfgminer version can be used.
53  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 14, 2013, 04:58:50 PM
with hashfast announcing 500 GH / chip .. this is ... dust in the wind ... all respect for your work tho !

What's their total cost for the chip, board, power regulators and cooling system ?
54  Bitcoin / Hardware / Re: - One String - a novel bitfury miner design - on: December 14, 2013, 04:52:10 PM
If the bitfury chips become available again, the higher difficulty requires a cheap board. A design like this has minimal BOM cost, so it will be a good solution.
55  Bitcoin / Hardware / Re: [ANN] Bi•Fury | 5+ GH/s USB Miner [FASTEST USB MINER IN THE WORLD][IN STOCK!] on: December 12, 2013, 06:32:23 AM
The firmware upload feature is built into the CPU, and because of the very limited memory space it has to make some assumptions about the way the USB mass storage device is used. Native Linux access doesn't work either.  The easiest way to restore the firmware is to use a Windows machine.

You can also write the firmware in Linux, using the mtools:

mcopy -o -i /dev/disk/by-id/usb-NXP_LPC1XXX_IFLASH_ISP-0:0 firmware.bin ::

Once you have the correct firmware, it should work on the Raspi, at least. I don't have a Mac, and I've never tested it on one, so there may be some problem with Mac compatibility.
56  Bitcoin / Hardware / Re: [ANN] Bi•Fury | 5+ GH/s USB Miner [FASTEST USB MINER IN THE WORLD][IN STOCK!] on: December 12, 2013, 05:07:36 AM
jedimstr, did you upload the firmware on a Mac ? If so, that may have caused a problem.
57  Bitcoin / Hardware / Re: [ANN] Bi•Fury | 5+ GH/s USB Miner [FASTEST USB MINER IN THE WORLD][IN STOCK!] on: December 10, 2013, 07:44:56 AM
I've made an overview of all the different firmware versions, and also included the upgrade manual and the protocol specification that is used between the bi-fury device and the miner software.

http://c-scape.nl/bi-fury/
58  Bitcoin / Hardware / Re: [ANN] Bi•Fury | 5+ GH/s USB Miner [FASTEST USB MINER IN THE WORLD][IN STOCK!] on: December 10, 2013, 06:57:07 AM
Added 100 and 110 degree limit versions.

http://c-scape.nl/bi-fury/firmware_100.bin
http://c-scape.nl/bi-fury/firmware_110.bin

If the hash rate is based on the number of shares reported by the device,  big swings are common because sometimes the device is lucky in finding a couple of shares close together, and sometimes it doesn't find anything for a longer period. Because the firmware supports difficulty > 1 shares, the swings can be more pronounced. As long as the long term average is good, I wouldn't worry about it.
59  Bitcoin / Hardware / Re: [ANN] Bi•Fury | 5+ GH/s USB Miner [FASTEST USB MINER IN THE WORLD][IN STOCK!] on: December 09, 2013, 08:30:28 PM
It looks like duplicate shares is generated when running without fan and temperature is getting close to 90C. Perhaps it is switching off and on again?
Correct. As soon as temperature goes < 90, the chips are enabled, and > 90 they are disabled. So if you keep it around 90C, it will keep switching on/off.
60  Bitcoin / Hardware / Re: [ANN] Bi•Fury | 5+ GH/s USB Miner [FASTEST USB MINER IN THE WORLD][IN STOCK!] on: December 09, 2013, 08:26:27 PM
I would think 120-125 deg C is very hot, that's why I set the upper limit at 90.

However, if you'd rather push the envelope a bit, and run the device at 125 deg C, I have uploaded a modified version at http://c-scape.nl/bi-fury/firmware_125.bin

Note that the voltage regulator has a maximum junction temperature of 150 deg C, and it's generating quite a bit of heat itself, so 125 degrees probably causes quite a bit of premature aging in the device. Of course, with the difficulty increasing rapidly, life span may not be very high on your priority list Smiley

Edit: I agree with intron. A fan is highly recommended...
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