A not long ago there was some noise in places I follow about Zynq FPGA boards surplussed from their role as controllers in retired cryptocurrency mining rigs, for way less than the price of even the bare FPGA SoC. I impulse bought one EBAZ4205 from “College Shop Store” on Aliexpress for $19.08 shipped to try them out, since it seems to to be the most common and documented flavor, and it showed up yesterday. Short version: they look awesome for the price.
As advertised, this one came with the microSD card socket populated, UART and JTAG headers populated, and Boot Select resistor moved to R2577 for SD (with some visible flux residue to show what was done). It did not come with a SS810 diode on D24 to make the big power connector usable, I’ll have to find and order something compatible because that is a much more convenient connector.
To do a quick proof-of-life test, I powered it from a bench supply, +12 on one of the DATA headers (I grabbed a test clip to get in without shorting anything), Gnd on the big power connector, hooked up a USB-Serial adapter to the UART pins (RX,TX,GND, left power floating to avoid thinking about levels) set picocom to 115200/8N1, and flipped on power. With the resistor moved it doesn’t do anything without an SD image, so I dd‘d the buildroot image suggested here (which I think is built from this repo )to a spare microSD card, popped it in, power-cycled, and watched proof of life on the serial terminal.
I have some other projects I’m trying to wrap up, so I’m not going to go deep with it right now, but the boards appear to be as promised, easy enough to work with and with an enormous amount of potential for the price – thanks ludicrously wasteful cryptocurrency nuts! If I get some time (…don’t count on it), I’d like to try to port Machinekit’s hm2_soc_ol to work on these boards, given their layout they should make superb standalone machine controllers.
References:
- Good hardware/setup reference: https://github.com/xjtuecho/EBAZ4205
- Vivado setup reference (Chinese): https://hhuysqt.github.io/zynq1/
- English narrative: https://embed-me.com/ebaz4205-recycle-a-cheap-crypto-miner-part-1/
Hunting suitable diodes to enable the main power connector, the supply diodes on these things appear to be SS810 Diodes, (Schottky, VrrmMax = 100V, If=8A, VFMax=0.85V, IrMax=1000uA) in DO-214AB packages. Which are surprisingly hard to find an exact match for. I think these mccsemi SK810L-TP are a suitable enough drop-in, available from digikey, though their $5 minimum shipping means I’ll be holding off until I need some other things from there and/or find out if any local friends who also ordered these boards need some.
Any schottky diode would do. I just used a regualar thru hole 3 amp. It jsut needs 400ma so even a 1a diode would do.
I ended up slow-boating a strip of 20 exact matches from AliExpress for pocket change to cover me and several friends who also bought boards.
I have a colleague considering a project using a substantial number of these things, so I was trying for a “clean” solution.
Otherwise, as you say, I would have rooted around in my box of assorted diodes and bodged in something I have on hand; probably a barely long enough to touch the pads but surface mount SS36, or ye olde through hole 1N5822 bodged over the footprint.