Updates: see
this post and
this one too.
Hi folks. I've built a mining board for myself and I'm trying to
gauge interest to see if it's worth putting in a large PCB order and
reselling them (fully assembled).
Attached are photos of the version 7.0 board. If all goes well I'll
be selling the version 8.0 boards, taking orders around 3-Oct and
shipping around 10-Oct. The boards will sell for $250 in the basic
configuration, which is:
- The board (85mm x 65mm)
- Spartan6 LX150-2
- Bypass capacitors
- Xilinx JTAG connector
- 10Mhz clock crystal
- Mounting holes for a standard Northbridge heatsink (two different
hole diameters; rotate the sink 90 degrees to change width).
- High-current Molex connector (see below)
The black 20-pin right-angle connector shown in the photo will not be
on the final board, and some of the unsoldered pads will change or go
away.
The board is designed to take power from a backplane (see photo) using
a high-current Molex connector. This connector is the same kind used
on ATX motherboards, but has a different pin count and keying so you
can't plug it in by accident (!). The Molex connector carries 1.2V
(high current) and 3.3V power, ground, one I/O pin, and all the JTAG
wires.
The backplane (sold separately for $160) has slots for six boards and
includes a SATA power connector and 48W power supply. The JTAG
chain enters via the backplane and snakes through all the boards, so
no extra cables are required. Airflow is meant to come in through the
side.
Extra options (includes parts+assembly):
- $15 for 12W power supply and SATA connector so you don't need the
backplane.
- $5 for a 20-pin connector carrying DONE, INIT_B, PROGRAM_B, ground,
and 14 general-purpose I/O pins. Or you can always solder this yourself later.
This connector means that if you decide to stop mining, you
can still use the board for plenty of other FPGA-related projects.
- $20 to upgrade from a Spartan6 -2 to a -3, although I'm not convinced
this is worth it. Parts are often "graded" into the -2 bin for reasons that
don't affect mining performance (I/Os and DSP slices).
Payment will be only via bitcoin; my margins on this are so slim that
it only takes one stolen-credit-card order to wipe out whatever
meager profit I'll make on two dozen boards. Escrow is fine as long
as the buyer pays; I'm still trying to figure out which service(s) to
use.
Anyways, please let me know -- zero commitment -- how many boards you
would be likely to order at the pricing and availability dates above.
That will help me figure out if I should place a large PCB order or just get
enough for myself.
Thanks!
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