I wanted to reverse engineer the USB adapter from ASICMiner for
Tubes/Prismas so I built one out of an old USB Blockerupter.  The
Blockerupter, like most (all?) USB-controlled bitcoin hardware makes use of
the CP2102 USB-UART adapter, just like the adapter from asicminer.  Here's
a picture of the adapter, showing which pins are which.


To use the blockerupter, you want to get rid of anything potentially using
the BE100 chip, or communicating on the UART.  Here's the blockerupter,
showing what I removed.  Some of this is optional, but I wanted to reuse
the inductor pads for wiring so make sure to get rid of big caps as well.


Once you've got a bunch of the stuff pulled, plug it into a computer and
check if it works.  The SI labs website has a handy tool for checking if
CP2102s are in working order.  Everything on the chip should be factory
defaults.


Now you need to wire the UART RXD and TXD pins to output wires.  Find the
smallest wire you can.  I used single strands from a stranded 24 AWG wire,
and it worked pretty well.  The RXD pin on the CP2102 goes to the topmost
left pin of the microcontroller, an Atmel 2313 AVR, and the TXD pin goes
to the leftmost top pin on the micro.  I jumped them from these tiny pads
to the inductor pads.  You can jump them where you think best, but don't
short to something which would interfere with the signal.  There is one
more issue.  If you look closely at the RXD pin on the ASICMiner adapter,
you'll notice that it is tied high (to 3.3V, not 5V) through a 1K
resistor.


We need to run a 1K resistor from 3.3V to RXD.  C5 and C6 are the output
capacitors from the internal regulator for the CP2102.  Jump from them to
RXD.  Here's a picture showing where all the wiring on the blockerupter
needs to go.  Remember, leftmost top pin, and topmost left pin from the
microcontroller.


It should function as a USB-UART adapter now!  Hook up GND, TXD, and RXD
as shown in the first picture and fire up your miner!  The final product
should look something like this.  I added some hot glue to keep the tiny
wires in place.


It seemed to work as well as the ASICMiner adapter, here's a screenshot
from a single prisma board hashing:


You should theoretically be able to use any CP2102 USB-UART with
a 1K pullup resistor from 3.3V to RXD in this fashion.

EDIT: Moved pictures temporarily so they will load.  I might mess with resizing them later.

--
novak

Wow - you are good. 

We would like to hear from you all.  He can do a run of UARTs for this.
If there is enough interest I will get him the funds and he can get them going.  I know they are hard to get and depending on the amount needed we can get the run going.
I have been working with him behind the scenes to get project going.  Novak is a talented guy that is for sure.

So everyone let us know here if you are interested and we will get it going.  I will give him what ever help he needs.

Thank you.

Person6278 PM'd me a while back, he picked up a USB-UART and got it working by adding a resistor:

https://bitcointalk.org/index.php?topic=865503

In unrelated news I've ordered a couple of UARTs as well, probably be here early next week.

--
novak

So, I got hold of the seller in the US, and they did not have sufficient stock.  I looked around for another US seller offering the same part but couldn't find one.  I did however, find even cheaper pricing from an oversea seller.  So I will be offering the adapters at $4.50 each (plus shipping, which should only be $2.50 in the US), and they will be delivered between 6 and 18 business days.  I guess shipping around the holidays is messy.  At any rate, it should only take me a couple days to rework them, test them, and get them back out.  

If you would like to buy one or more, just PM me or email sales@gekkoscience.com

Edit:  Link to the group buy page: https://bitcointalk.org/index.php?topic=882348

--
novak

It's a USB adapter to run Tubes or Prismas off a standard host controller like a laptop, Pi or beaglebone, running cgminer on any pool, instead of AM's BlockErupter controllers with no failover options and a broken stratum implementation.

Basically he's making them because they're hard to get from ASICMiner.

There's info enough on the DIY, but he's got 'em priced pretty reasonable in the Group Buy. Looks like he just finished testing a bunch of 'em, probably ship orders out tomorrow. We've got some Prismas in hosting running off stock AM USB adapters and they're a heck of a lot better than the AM BE controllers.

How did you get you boards to hash under Windows?  On my win7 machine all I get are LIBUSB errors regarding syncing.  The same setup works fine in

Linux.  Self compiled CGminer 4.9.0. with --enable-blockerupter config.  I compiled it on the same machine using Mingw.

Hmm.  The distributed windows binary would not even "see" my units.  The one I complied myself in Mingw sees them, but produces many errors then crashes right away.

I am using the drivers installed by Zadig and an adapter I made.  This exact hardware work fine under Linux but that is not an option where these are.

I am not at the location currently.  The errors referenced "usb timeout"  and something about "returned 00" or some such thing (bad memory).  Might post a screenshot

tomorrow.  I will be at that location then.

Edit: Unexpected value 00