GekkoScience BM1384 Project Development Discussion

[Unacceptable]

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.

U funny!!  

Personally,if it weren't for video games,I'd be back to drinkin & druggin.......    19 years C & S on April 1st,god DOES have a sense of humor!!!!!!!! 

Old Unreal Tournament GOTY got me into gaming & building PC's,then Medal of Honor:Spearhead,COD 2/3/4/5 & the newer Battlefield 3 & 4 saved my life since then!!!

Great anger management & have met & made friends all over the world  

Looking forward to pics & info!!  

[1714482409]

1714482409

[1714482409]

1714482409

[Biodom]

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

fried potatoes with ice cream...you guys are the worst  

[sidehack]

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.

[Biodom]

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.

don't play games, but using internet to browse is my weak spot, i admit, but if not for this weakness, i would have never heard of bitcoin, for better or worse.
Cheers

[Finksy]

Aren't we all in the same boat!  Mining for information on the internet came way before mining for bitcoins for this guy.  I miss playing games, but life happens.  Family, responsibility, and other fun projects are way more important to me.

Anyone else grow up in the heydays of Quake TF? Man I miss those times...

[quakefiend420]

Aren't we all in the same boat!  Mining for information on the internet came way before mining for bitcoins for this guy.  I miss playing games, but life happens.  Family, responsibility, and other fun projects are way more important to me.

Anyone else grow up in the heydays of Quake TF? Man I miss those times...

See username....

[sidehack]

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?

[hurricandave]

Time to get out the CamCorder!

[TheRealSteve]

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

Fail @ BTC0.01 ( don't mind losing that bet - though I hope it's not because it ends up being a release of the magic blue smoke )

[sidehack]

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.

[valkir]

Great job sidehack. cant wait to see the final product.
 

[TheRealSteve]

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 I owe you BTC0.005?  Fair enough  Sounds like good progress all around

[hurricandave]

So, six stick's with extra cheese 

[sloopy]

Sidehack I am sure you have plenty of people ready to throw their money at you, but please add me to any list you may make in the future as interested in buying at least two of everything you release. If you end up with anything not already promised for field testing I will gladly pay for those as well.

I feel that way because of your attitude to the community, the support you have shown me, and my own love of the tinkering.
So seriously please keep me in mind. I know some of my questions are n00bish but it is because I like to ask about everything and anything to see what experienced folks think.

I am also not that far away from you guys. I have techs driving between Moberly, MO and Tulsa to NE Oklahoma in the Bartlesville area all the time. I used to make those trips and love driving the windy, hill roads through MO. 

Good Luck and don't let the smoke out!

[sidehack]

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.

[sidehack]

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.

[Searing]

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.

thanks we appreciate your efforts...i have no idea what the frack you are talking about..but find it 'soothing' none the less....hope it succeeds I need a 'toy' even at a loss on coin
vs what it could mine for when you get it out........I'm a sucker for the shiny LCD's and cgminer in putty....heh .....soothing...

[sidehack]

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.

[novak@gekkoscience]

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.

Yeah I've not yet written a cgminer driver but I'll go through and see what's required to convince cgminer to accept it as a U3 or something similar. 

I think a couple things would need to be done:

Probably cgminer can't detect the component because some static setting in either the chip or cp2102 doesn't come up with something it recognizes- even the U3 was BM1382 after all.  I can probably fix that quickly by looking at a few settings on existing miners.

I'll have to figure out how the heck to get timeouts and whatnot working, I see different values on a lot of settings for AMU and AU3 which leads me to believe that this newer chip will require at least some changes.  That... Might require almost nothing or it might be complex.  Hopefully the chip will at least start up with U3 settings even if it runs poorly.

--
novak

[sidehack]

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.