All my boards are designed for integrated current measurement. But people (especially in Bitcoin) are cheapskates and usually didn't want to spend the extra three dollars for a feature that wouldn't get used.

I think we've got one of these at the shop. Novak spent more time playing with it, I'll see if he's got any notes on the thing.

You know the BM1384 can do under 0.35W/GH, right? I worked over some numbers a month ago speculating S2 upgrade kits, with suitable chip density they could make a 3.6TH miner off a 1KW PSU with the same power density (and therefore same fan volume) as the S2 if they really felt like it. It's possible to get 0.21W/GH from 28nm if done right, and pretty easy to do with 22nm.

I'd be surprised if a 6-board kit came in under $500, and honestly $600 seems more likely. Looking at around 2.6TH at about 0.3W/GH would be a steal at under $400, when you'd have to put down about $750 for that hashrate (at worse efficiency) from S5.

I believe there's timeout data in the datasheet, for what that's worth. I'll have to clean up the Vcore regulator a bit for you but the thing should be pretty movable from one bench to another. Those breakout boards turned out pretty nice. Remains to be seen if they work properly though.

I guess at some point I should make a chart of the page of power data I got from the regulator. I'll probably make it better and then have to run all the tests again, but today I got output ripple and efficiency info from about 65 current/voltage setpoints before jacking with the BM1384 breakout board.

I'm really hoping there's nothing wrong with the chip itself and there's some trivial reason I'm not even seeing serial return data. I might reflow the chip tomorrow and shift it around a bit, make sure all pads got good solder contact. Any software poking that'll have to be done to cgminer driver will probably have to wait until at least Monday, if not later.

So, the chip is mounted on the board and receiving serial data and running off the Compac regulator. But it's not sending any serial data and cgminer doesn't recognize it. That's not terribly surprising, really. I'm hoping Novak can software up an answer for convincing cgminer to recognize it, or I find yet another hardware issue with my serial level shifter or something.

It did once report an Icarus error wrong device detected something or other, and occasionally it throws LIBUSB stop errors on unplug, but nothing has been consistent.

Anyway, right now it's quittin' time.

Tested the regulator up to 750mV 5A, which should be able to run between 9 and 10GH. Regulator power at that point is 4.34W, so factoring in power for the rest of the stick you're probably looking at 4.5W or so to get there.

At 650mV I tested up to 5.2A, which should run 10-11GH off a regulator input of 3.94W, so probably about 4.2W input. Past 650mV with the .125ohm load, I'm not sure what was kicking on (internal OCP shouldn't have been a factor yet, nor should OVP) but the chip was shutting down then ramping back up rapidly.

I'm still not satisfied with the output high frequency ripple, nor am I impressed with the load regulation. Probably an artifact of the switch noise on the output getting through the feedback compensation is causing the output voltage to increase with output current. I didn't notice it until about 2-3A output, which means it shouldn't be a factor for a stock USB power range, but this thing's supposed to be designed to obliterate USB power if the user wants it to. I just don't want someone to crank up the clock on a particular voltage setting and then find out the voltage jumps up to shutdown point.

It's probably good enough to start initial testing with the chip, though. I'll wire up a breakout board and see if I can't get cgminer talking to an ASIC before clocking out tonight.

I really do hope that happens. What I fear is more likely, though, is that a few industrial players better positioned to ride out the halving will buy up the dying farms and consolidate even more hashrate under fewer and fewer roofs.

Well the good news is it appears to work. There was no smoke, which I was actually expecting. But I need to do something about the high-frequency ripple on the output because it's killing the overvolt protection trip once the current gets very high. So some of the good news is, the overvolt protection works. Though I think a lot of what I'm seeing is actually ground noise on account of jumper wires since this is only a one-sided board.

Yep, better grounding and killing some added capacitance on the feedback loop is helping. I'm not exactly stable but it's at least working now with 740mV output (the top end, not bad since the calculated top end was 750mV) and 0.83 ohm load. So only 890mA output, or about 0.66 watts. The input power is approximately 5V 160mA, so 0.8W, giving this an efficiency of a bit over 80% at that low power. Which ain't bad because the peak efficiency should be about 3A output and at low currents the controller's probably in diode mode (or worse, forced CCM) so low-end efficiency is expected to suck. I should see at least 85% for most of the load range. Increased output capacitance with low ESR should help the ripple. There's tweaking to be done but so far I'm quite optimistic. Tomorrow I'll load-test it up to several amps and then see about strapping it on a populated BM1384, see if I can't get a chip talking to cgminer and then we'll be seriously rolling.

If I had a family I'd probably prioritize it above building awesome stuff.

I actually was asked about bitcoin by a guy at church about two years ago, and knowing nothing about it, I looked it up when I got home and spent about two days reading.

Additionally, about to test the Compac regulator circuit. Taking all bets - work, smoke or fail?

Unacceptable - I was raised on a farm, the son of an English teacher and a carpenter. We had books and projects, no video games. I was one of two CompScis in my graduating class at college that didn't play regularly.

Biodom - no, it's called "Dairy Queen". Pretty great stuff.

Also, I was supposed to have the evening off but it turns out that sitting on the couch is super boring compared to working on awesome stuff. I'm gonna try and build a regulator tonight.

If by "salad" you mean "fried potatoes and ice cream", then yes. We ate lots of "salad".

What would price and shipping be on a Jupiter that was also in the case? Or better yet, what would price be on a Jupiter still in the case if I sent a shipping label?

Well, if you know me you'll know I'm outspoken on three things above all else.

1. Video games are a foolish waste of time, and that energy spent on entertainment could be better spend on building awesome stuff.

2. CHEESEBURGERS

3. Butts are funny

The third thing doesn't really enter into this discussion substantially, except perhaps peripherally that cheeseburgers come on "buns" which are especially humorous when delivered in pairs. But yeah, no video games are being bought with the sandwich fund. Friday's cheeseburger day comes out of my own pocket, but I will note that the crew ate dinner on Wednesday from the sandwich fund and two-thirds of us ate cheeseburgers.

So. Today is shaping up to be a good day.

Compac PCB is tentatively complete. BM1384 breakout boards just arrived, as did all the parts to populate it, and all the parts for the Compac regulator test board. Also it's Friday, which means $2 cheeseburgers at the Waffle House. So this afternoon I get to start populating boards and testing circuits and eating cheeseburgers and other awesome stuff. If I can ever find my camera I'll put up some pictures of actual hardware later. Because if we have pictures of actual hardware you're a lot less likely to think we're just scamming people for cheeseburger money, right?

Yeah, I know better than to expect any real resolution here.

What sucks is, I really like the idea of third-party manufacturers making non-crappy miners, but Technobit is sorta ruining the landscape. It's not gonna be difficult to be better at delivery and customer service than they are, but will anyone even be interested in independent manufacturers if all the representatives are either overt scammers or only mostly scammers?

He mentioned in this thread that he'd look into it, but that was five or six weeks ago.

(plus what, a hundred for shipping?)

Hey Marto, did you ever follow up and find out where this guy's boards went?  I still have one hundred air coolers that have been sitting in boxes in the corner of my hosting room for EIGHT MONTHS without a single word.


wait a second...


Hey Marto, did you ever follow up and find out where this guy's boards went?  I still have one hundred air coolers that have been sitting in boxes in the corner of my hosting room for EIGHT MONTHS without a single word.