So now with the release of the schematics from Avalon, it's official: I have been right all along about the daisy chaining, and also the use of the Spartan-6. Any design that does not use a subsystem with multiple serial ports working asynchronously will not be efficient. We will be using the original Avalon design, but are not clear yet on the hashing unit power supply because of parts availability.

Ok. Let me try to explain some details about how the hashing works, and why either an FPGA or CPU can work, so that we can move beyond this.

In order for the hash engine to work it needs 3 pieces of data:

( midstate, fixed_data, nonce )

Midstate and fixed_data are provided for each work unit by cgminer.

Nonce is a 32 bit range that will counted up through so that every value is hashed, ie max 4 billion odd hashes.

When cgminer sends a work unit to the Avalon it sends some control info (like fan speeds, module number, asic count) and then the (midstate and fixed_data), and then it appends on the starting nonce value for each ASIC in the target chain module. So for Avalon that is 10 copies of the nonce start value. This all comes down USB and into the FTDI chip which sends it into the FPGA.

The FPGA accepts this in a super long shift register and acts on it. It has to send a stream of data for each ASIC in the chain - so that means repeating the ( midstate, fixed_data, start_nonce_value )  serially into the data input of the ASICs. This is quite a bit of data actually:

( 256 bits midstate, 96 bits fixed_data, 32 bits nonce ) x 10 ASICs in chain = 3840 bits.

It holds the midstate+fixed_data and repeats it for each ASIC appending on the nonce_start.

Avalon uses an FPGA because it's doing this process for each of the 32 modules it contains because it is the one central controller in the box.

The way Klondike works is different but results in the same data going into the ASIC.

Klondike has a PIC controller with USB integrated. So it talks to cgminer just like Avalon, but will use a different driver. This driver will send the (midstate, fixed_data) to Klondike via USB and the PIC stores this in it's RAM (44 bytes total). It doesn't need to calculate and send the nonce, the PIC will take care of that. So total data sent for each work unit is 44 bytes.

The PIC will take this data in RAM and serially push it into the ASICs and then append on a nonce start value (by masking the high 4 bits, thus giving it a range equal to 1/16th of the total). It will repeat this for each ASIC in the chain. Since it's only managing it's own module it doesn't have to switch and control 31 other modules like the Avalon FPGA.

The Klondike has 16 ASICs but I have split them into 2 banks of 8 each. This allows pushing the data in twice as fast, and also means if one ASIC is damaged then only 8 cannot function, instead of 16. While the data is pushed into an ASIC the hashes it calculates are invalid, so the faster the new work start data is pushed in the less time the hashing is stalled.

Klondike also performs a few secondary tasks. It sets up a PWM register to control fan speed. It now and then takes a voltage reading off the thermistor or internal sensor. And it also accepts work data from the USB host that is not intended for it's own ASIC chains. A 44 byte work unit can arrive that is for some other module. In this case it simply receives it and sends it right out again on the I2C bus. Since the PIC has a hardware I2C controller this takes very little code or work.

So the same thing happens in both systems but in Avalon the FPGA has to handle 32 times more data than the PIC. With 16 ASICs at 282 MHz a nonce range of 32 bits will take about,

2^32 / 16 / 282,000,000 = 0.95189878 seconds.

The PIC has to receive 44 bytes of data in just under a second for itself, and then repeatedly shift it into the ASICs as initialization for hashing. This should take about 3% or less of it's time depending on how fast the ASIC shifting is done. The other 97% of it's time it's waiting for results, relaying data or fiddling with it's fan. Since most of these are handled by interrupts it's basically idling.

I may stick a 320x240 LCD touch screen on the front of my Klondike master so I can see status. The I2C bus would allow this and give the PIC something to do when idle.

Burnin.

Without revealing too much about your boards can we get any updates on design specifics. I know comparison with Bkkcoins version of a DIY Avalon will help many see that diversity is in the marketplace and will help everyone a great deal to get into more CHIP group buys. We do need as much information as possible so that we can settle people into the alternatives. BFL has a very tenuous hold on the market right now and the more project leaders can reveal the better to loosen BFL's grip and allow for more freedom in the market place.


Seeing that there is no FPGA means a lot so you are in agreement that most of these 10 -16 chip board designs and larger configurations do not need it?

Also in terms of stacking we are looking at a 600 W PSU that could supply power to how many boards?

So in terms of heat sink what will you be using Aluminium extruded like on the Avalon rigs?

The heat sinks will be connected to vias to dissipate heat or do you have something else in mind?
 
My apologies if this has been answered before in the thread. I will continue reading through and revise if necessary.

I'd like to add... if there's anything you need, please let us know! I'm sure it's the least we can do for the time you're putting in.

FRC is the openly available portion that miners can obtain while FRC-F is the portion of each block that is given to the foundation.

# 10/20 Avalon chip module - 2.82/5.56 Ghash/s nominal speed
# 4 Layer thermally enhanced PCB
# PIC32 native USB-Controller
# CAN-Bus inter-module communication (Only one USB connection for up to 32 Modules)
# Power Connectors: 6Pin VGA, barrel jack for wallwart, power-stacking-connector.
# Power requirement: ~20/40 Watts @ 12V
# Onboard 25A/50A switcher for core voltage
# Easy stacking option
# Host protocol: Avalon emulation
# Temperature controlled Fan

Indonesian Mining Rig:

I have been looking into the possible building of the Klondike board here in Indonesia using a Japanese company based here and it looks very promising. First the Klondike board is nearing design completion and some important things are going to be tested on the boards soon. Avalon just released more information on the chips so the design is able to move forward as pretty much in line with the specifications. I am interested in putting up a website probably in July so that Indonesian can read about the updates as they come in and lay out plans and schedules so that you can follow when we expect to have working miners for sale in Indonesia. We will have prices for these miners as we get closer to the date.

Will you provide an assembly service as well?

Now that you are hoping for a few different boards, can you give so updates for cost with and without parts? I am strongly considering going in on the funded ASIC group buy, and I am just trying to figure out how many I can afford. I am not looking you to lock into a price, maybe just a ballpark. Especially for the 64 chip board you mentioned.

If I had to ball park a kit price right now I'd throw out numbers like:

ALL QTY 1 --- SUBJECT TO CHANGE

(board + parts) (without ASIC, heat sink, ATX PSU, cables)
Klondike 1 - $16  (I did a design and parts list this evening, and board partly done)
Klondike 16 - $35
Klondike 64 - $100

(board only)
Klondike 1 - $6
Klondike 16 - $12
Klondike 64 - $25

PDF Assembly Manual included (hopefully). Shipping not included.

I'm not planning to get into full assembly myself except maybe for the Klondike 1 (dongle).
I will supply boards/kits at wholesale pricing to other assemblers.

I understand why people are predicting consolidation of miners. The very fact that chips are priced in BTC is aggravating that monopoly (rich get richer scenario)

I don't disagree that many will quit mining, but I do disagree that hobby and general "normal" people mining will die. It won't

Why wouldn't a person have a few units stacked up in his shed, wired up to a solar panel, churning out a few blocks? it's the bitcoin equivalent of a savings account, it won't make the person rich and they understand that, but it's extra coin they wouldn't have otherwise. Not every miner is an enterpriser.

Avalon just released the first segments of their design. This means that there will probably be clones by OEM's in a few weeks.

Has BFL shipped (2%) yet? Nah. Still waiting.

How many boards could be safely/robustly supported via USB daisy chaining per host [PC,Pi,Etc]?

I discussed this briefly with some people when the ASICMiner USB devices were announced, and there were a couple of people complaining that in their experience connecting 15+ devices via USB usually led to problems, even with high-quality powered USB strips. I have little experience in connecting lots of USB devices so I can't really say, but this might be something worth checking out for users that are aiming to have lots of boards.