Klondike - 16 chip ASIC Open Source Board - Preliminary

[nekonos]

Hello BkkCoins

I am worried with the availabilities of microchip PIC16LF1459-I/SS. Microchip information  PIC16LF1459-I/SS   Estimated Availability:  05-Aug-2013

I think we would have to consider the possibility of alternatives or change package.


What do you think?

Thanks

Cheers!!

[chaoztc]

@Vigil: buck regulator switches of at 145°C +/- 20°C
see page 39 of the pdf, the IRF will be very hot.
http://www.irf.com/product-info/datasheets/data/ir3895m.pdf

@nekonos:
see https://bitcointalk.org/index.php?topic=190731.msg2329781#msg2329781

[SebastianJu]

Hm... i guess a bigger board wouldnt increase assembly cost very much. But a board with 2 chips less means one have to buy a complete board more for each 7 boards.
I hoped its not such a big thing to implement. The original avalon miner it seems, can be overclocked till 395MH/s instead 282MH/s but i believe i read they are stable at 375MH/s only. Maybe Klondikes can handle overclocking better and more stable?

Im not sure what to do. I tend to say chosing the boardsize that has the lowest manufacturing and assembly cost per chip is the best option. And when it has maximum overclocking capabilities.

[marto74]

For sure board price is connected with size.

[ecliptic]

I am an engineer with a background in aerodynamics/fluids and am capable of performing Heat/CFD simulations. Is there any way I can contribute to the heat sink/dissipation design. I can't promise anything but I can try if I had more understanding of what the goals/design are.

Goal:  Keep shit cool, lol.  Im sure you could grab the component measurements off the net or make a rough estimate based on the PCB pictures shown in the thread and make a rough, scalable design.

I need to know how cool. I need estimates of heat generation of the chips (at least) and possibly the other components on the board. Fan or no fan? Stock components or custom (for the heat sink)? etc.

Only the Avalon chips should require heatsinking.  They are QFN chips with a thermal pad, each generating a few watts of heat.  The pad solders to a PCB pad with many thermal vias, and then the heatsink is mounted on the opposite side.  The general plan i have seen from all PCB assemblies is to use one heatsink that covers the entire or almost the entire board.  

I don't think any of the designs have needed fans thus far but i'm not sure if they've actually been tested

I don't think any stock heatsinks work with this, but it might be possible to find one that fits the square area and then CNC drill (or by hand) the 4x mounting locations for the K16 board.

I'm trying to figure out a good way to do heatsinking as well, it's currently a single point of failure with sourcing

(oh, and the thermal resistance to the top surface of the chip is massive because of the insulating material in the chip/carrier, so adding heatsinking onto the chips themselves wouldn't help)

[ecliptic]

Hello BkkCoins

I am worried with the availabilities of microchip PIC16LF1459-I/SS. Microchip information  PIC16LF1459-I/SS   Estimated Availability:  05-Aug-2013

I think we would have to consider the possibility of alternatives or change package.


What do you think?

Thanks

Cheers!!

I ordered this from the manufacturer about a week ago and the lead time was 2 weeks

For sure board price is connected with size.

Not that drastic though.

What about adding another regulator and keeping everything else the same?  Seems to be the easiest, all the supplies are tied together, right?

Well correction, the easiest is just populate ~14 of the chips and make more pcb assemblies.

[ryepdx]

I am worried with the availabilities of microchip PIC16LF1459-I/SS. Microchip information  PIC16LF1459-I/SS   Estimated Availability:  05-Aug-2013

I think we would have to consider the possibility of alternatives or change package.

You can also use the PIC16LF1459-E/SS. The only difference appears to be wider operating temperature range. (-55C to +125C v.s. -55C to +85C)

BkkCoins has also promised a QFN version of the board which will use PIC16LF1459-I/ML.

But you're right, the PIC is going to be the big bottleneck in this operation. With the number of chips ordered from Avalon, if only half get used in K16s, we're looking at a need for 14k+ PICs.

Edit:
With 256 PICs coming my way (90 in hand and 166 shipping July 11th), I may end up with a surplus. If anyone is short PICs in the future, let me know and I might be able to sell you some.

[ecliptic]

I am worried with the availabilities of microchip PIC16LF1459-I/SS. Microchip information  PIC16LF1459-I/SS   Estimated Availability:  05-Aug-2013

I think we would have to consider the possibility of alternatives or change package.

You can also use the PIC16LF1459-E/SS. The only difference appears to be wider operating temperature range. (-55C to +125C v.s. -55C to +85C)

BkkCoins has also promised a QFN version of the board which will use PIC16LF1459-I/ML.

But you're right, the PIC is going to be the big bottleneck in this operation. With the number of chips ordered from Avalon, if only half get used in K16s, we're looking at a need for 14k+ PICs.

That's not a huge volume to the manufacturer though, it's just up to whatever their lead time is.

Also - is there any (practical) limit to how many k16's can be chained and controlled by a single computer running cgminer?

[nekonos]

I am worried with the availabilities of microchip PIC16LF1459-I/SS. Microchip information  PIC16LF1459-I/SS   Estimated Availability:  05-Aug-2013

I think we would have to consider the possibility of alternatives or change package.

You can also use the PIC16LF1459-E/SS. The only difference appears to be wider operating temperature range. (-55C to +125C v.s. -55C to +85C)

BkkCoins has also promised a QFN version of the board which will use PIC16LF1459-I/ML.

But you're right, the PIC is going to be the big bottleneck in this operation. With the number of chips ordered from Avalon, if only half get used in K16s, we're looking at a need for 14k+ PICs.

Yes, thanks for replys. I ordered some PIC16LF1459-E/SS , two weeks time for shipping.

Probably in this moment for assembly "ordered" boards. needed 6.000 PICs in next 2 month.

[ecliptic]

I bought a number of extra PICs just in case and possibly for future builds.

For DIY users i can provide some PIC16LF1459-I/SS if they cannot source it

[marto74]

I am worried with the availabilities of microchip PIC16LF1459-I/SS. Microchip information  PIC16LF1459-I/SS   Estimated Availability:  05-Aug-2013

I think we would have to consider the possibility of alternatives or change package.

You can also use the PIC16LF1459-E/SS. The only difference appears to be wider operating temperature range. (-55C to +125C v.s. -55C to +85C)

BkkCoins has also promised a QFN version of the board which will use PIC16LF1459-I/ML.

But you're right, the PIC is going to be the big bottleneck in this operation. With the number of chips ordered from Avalon, if only half get used in K16s, we're looking at a need for 14k+ PICs.

Yes, thanks for replys. I ordered some PIC16LF1459-E/SS , two weeks time for shipping.

Probably in this moment for assembly "ordered" boards. needed 6.000 PICs in next 2 month.

Just wait with big orders ...
Everything happens - new boards dims, new controler etc.
Just wait positive tests from BKK

[Jumpsu]

Can this fan be helpful on this project, size: 92x92mm and price is 1,25euro

http://webshop.nedis.com/en-us/1111817/cmp-fan24

[BkkCoins]

Hold that thought! IRQ announced the IR3847 SupIRBuck 25A back in March. Its pin-out is slightly different from theIR3895, but still in the PQFN 5x6mm package. Like the theIR3895, the IR3847 does not require a heatsink at its rated capacity.

Though there are two disadvantages. First it’s 25 to 50% more expensive than the IR3895 (no big surprise). The second issue is more pertinent - the availability of the IR3847.

http://www.irf.com/product-info/datasheets/data/ir3847m.pdf

http://www.mouser.com/ProductDetail/International-Rectifier/IR3847MTRPBF/?qs=%2fha2pyFaduh%2fXEfQX9qpOqsExJAQZ85xEuH%2ffjP3Ys6cnVXvB1KVwg%3d%3d

I didn't know about that. I guess it wasn't listed back in April when I started. Once I get hashing going I'll work on a board change to support this reg instead. This is the easiest, lowest cost way to get adequate current for over clocking. The problem will be factory lead times on a new product and sourcing the Cyntec inductor. Last time I went with the Murata due to difficulty tracking down the reference inductor. It's a bit less efficient using the Murata inductor but it's much more available.

[CumpsD]

Turning K16 into a 20 chips board would make it direct competition with burnin's 20 chip boards

(And I happen to have bought a number of chips dividable by 20 :p)

[marto74]

Turning K16 into a 20 chips board would make it direct competition with burnin's 20 chip boards

(And I happen to have bought a number of chips dividable by 20 :p)

dividable to 20 , it's also dividable by 10

[turtle83]

Low priority feature request: Have some kind of identify command. Issue this command to a running/idle K16 to make its led blink in some pattern. I think cgminer has some provision for this.

[BkkCoins]

Low priority feature request: Have some kind of identify command. Issue this command to a running/idle K16 to make its led blink in some pattern. I think cgminer has some provision for this.

There is already an Identify command, and all commands trigger an LED blink, though not in some pattern - just about a 1/4 sec flash.

[turtle83]

Low priority feature request: Have some kind of identify command. Issue this command to a running/idle K16 to make its led blink in some pattern. I think cgminer has some provision for this.

There is already an Identify command, and all commands trigger an LED blink, though not in some pattern - just about a 1/4 sec flash.

perfect

[chaoztc]

what about placing some connectors on the v2 design of K16 to piggypack a stronger powersupply on a addon board later?

[Enigma81]

Hello BkkCoins

I am worried with the availabilities of microchip PIC16LF1459-I/SS. Microchip information  PIC16LF1459-I/SS   Estimated Availability:  05-Aug-2013

I think we would have to consider the possibility of alternatives or change package.


What do you think?

Thanks

Cheers!!

as mentioned, the PIC16LF1459-E/SS is a perfectly acceptable cross.  So are the PIC16F1459-E/SS and PIC16F1459-I/SS.

The only difference is that the LF can run to a slightly lower voltage (1.8 vs 2.3) - I don't believe BKK's design runs the PIC that low though, so the F is fine.

Enigma