2011-10-16 00:00 from the description, it may just be PWM+FET 2011-10-16 00:02 well, that circuit is nothing else 2011-10-16 00:04 unless you want to spoil your efficiency with a series-R you'll always need a schottky diode (or seconf FET) and a choke 2011-10-16 00:07 should I support him with a small run and opening up the design? 2011-10-16 00:07 I will find out more data points first :-) 2011-10-16 00:27 wpwrak: rc4 related question - can Adam start with the design verification of the new gate/4.4v reset circuit? 2011-10-16 00:28 we have sold over 30 rc3 already, not bad :-) 2011-10-16 00:29 one open question was the CE0/WE# pullup, my understanding is that you already verified that at least CE0 does no harm? 2011-10-16 00:29 even if it doesn't help much, should we still add it? 2011-10-16 00:32 maybe someone knows: what will happen if I accidentally swap the wires of an LVDS pair? will it explode? will it work? 2011-10-16 00:34 the one big open question about rc4 for me is whether we should change the VGA connector to DVI-I 2011-10-16 00:35 if we do that, we have to change the acrylic side panel, we need to source a DVI-I to VGA adapter cable 2011-10-16 00:38 the box printing also needs to be updated then 2011-10-16 00:38 we need to decide whether we want dual-link or not 2011-10-16 00:38 possible reasons to not want it: 2011-10-16 00:39 1. difficult to route the wires space-wise 2011-10-16 00:40 2. even if not difficult, waste of fpga pins for no practical usefulness (that depends on how many free pins are left, and how likely it is that anybody will want to use those wires) 2011-10-16 00:40 actually it could be a nice way to get wires out, for hacking purposes :-) 2011-10-16 00:40 so anyway, that's the only big open question 2011-10-16 00:40 dvi-i now or stay with vga... 2011-10-16 00:47 after hellow world with CMD bit of ubb today I will try to have CLK = 0 and CMD  = 1 via MMC 2011-10-16 00:47 btw rc4 will include a non fully populated M1 target for hardware people? i even actually wanted to buy a M1 the other days but price still high ... tought at least for me 2011-10-16 00:47 no idea how to check with scope yet. I took the scope and it is next to me 2011-10-16 00:47 sleeping :) 2011-10-16 00:47 and others i had talked about M1 and hhdl 2011-10-16 00:48 kristianpaul: what do you want to leave out? describe the product to me that you would like to buy 2011-10-16 00:51 a M1 with no VJ accesories, no VGA and better exp bus (more pincs and dedicated clock lines) 2011-10-16 00:51 no case either at least with your prices ;) 2011-10-16 00:51 ot make that an option 2011-10-16 00:52 i do wonder if that can reduce price at least up to 200usd? 2011-10-16 00:53 ok, one by one 2011-10-16 00:53 :) 2011-10-16 00:53 for "better exp bus", I asked many times but got very little feedback still 2011-10-16 00:53 *g* 2011-10-16 00:53 please help us by clearly making some suggestions what that 'better exp bus' would be 2011-10-16 00:53 specifically 2011-10-16 00:53 by definition a perfect 'expansion bus' is hard 2011-10-16 00:53 sure 2011-10-16 00:53 because you don't know what the expansion will be 2011-10-16 00:53 :-) 2011-10-16 00:54 but just saying "better" doesn't help much either :-) 2011-10-16 00:54 you are probably one of the guys with the most thinking into the expansion bus by now, next to Sebastien or Werner 2011-10-16 00:54 but double the number of pins and adding at least two dedicated pins for clocks sounds better? 2011-10-16 00:54 specifically 2011-10-16 00:54 need a patch 2011-10-16 00:54 :-) 2011-10-16 00:54 please understand how small our community is 2011-10-16 00:54 sure :) 2011-10-16 00:54 you are holding prime knowledge in your brain :-) 2011-10-16 00:54 yes 2011-10-16 00:54 I need an exact schematic diff 2011-10-16 00:55 which pin do you want to go where 2011-10-16 00:55 and how do we preserve hardware compatibility with the expansion header we have now 2011-10-16 00:55 so "better expansion bus" - yes, I'm very interested 2011-10-16 00:55 always was 2011-10-16 00:55 but what is 'better'? :-) 2011-10-16 00:55 you tell me 2011-10-16 00:55 I think we should preserve compatibility with our current header 2011-10-16 00:55 ok, i got your idea 2011-10-16 00:56 did we change the expansion header between rc2 and rc3? 2011-10-16 00:56 ha, easy if i drop VGA i have some "clock dedicated" pins from there, problem solved ;) (kidding) 2011-10-16 00:57 I thought there was a change somewhere 2011-10-16 00:58 dont remnber i dint read too much about rc2 at that time 2011-10-16 00:59 ok let me check that now, in the PDF schematics... 2011-10-16 00:59 what do you mean with "no vga"? 2011-10-16 01:00 remove vga related layout and components from the design 2011-10-16 01:03 don't understand 2011-10-16 01:03 why that? 2011-10-16 01:03 what's the display output then? 2011-10-16 01:04 ok I checked the history of J21, the current expansion header 2011-10-16 01:04 looks like it is unmodified between rc2 and rc3 - good 2011-10-16 01:04 I think we should preserve that J21, or at least mechanical and electrical compatibility with it 2011-10-16 01:05 if you have ideas how to improve J21, add to it, add a second one, etc. please specify them clearly 2011-10-16 01:05 ok 2011-10-16 01:05 I absolutely want to roll such improvements into new runs like rc4, but they need to be clear, then others have a chance to react, and if they don't then it will just show up :-) 2011-10-16 01:06 I think it's already clear there cannot be the perfect expansion header 2011-10-16 01:06 by definition 2011-10-16 01:06 expansion expands into the unknown 2011-10-16 01:06 sure 2011-10-16 01:06 and there are too many subtleties one may realize later "oh, it would be nice if one pin would come from this other bank" etc. 2011-10-16 01:07 one thing we can do is to maintain stability for the expansion header we have now 2011-10-16 01:07 compatibility 2011-10-16 01:07 heh 2011-10-16 01:07 so if anybody makes a board or connector for that, they can carry it forward 2011-10-16 01:08 kristianpaul: please explain 'no vga', I still don't get it 2011-10-16 01:08 you mean an m1 without any display? 2011-10-16 01:08 yes 2011-10-16 01:08 or at least thinking about not populate some components in current PCB (DMX, MIDI, Video-in, DAC) 2011-10-16 01:09 My first concern is price, features could get done next :) 2011-10-16 01:11 But i do understand there is few people, and will consider a patch before i talk about (will be nice if) features again. 2011-10-16 01:11 nah talk is better than silence 2011-10-16 01:11 I just want to move from talk to action 2011-10-16 01:11 and that requires more specifics 2011-10-16 01:11 look at J21, think about it :-) 2011-10-16 01:12 as far as I know nobody right now uses this header 2011-10-16 01:12 we don't need to maintain compatibility with something that doesn't exist 2011-10-16 01:12 you know you don't want *me* to do that ;-D 2011-10-16 01:13 but it would be nice, whatever J21 improvement we make in rc4, that a future user of the header could still support rc2/rc3 as well, unless he needs a feature that was added only in rc4 2011-10-16 01:14 anyway not populating things for price cutdown doesn't make sense on a batch that small 2011-10-16 01:15 what's J21? VGA standard plug? 2011-10-16 01:16 no VGA, just a expastion header 2011-10-16 01:16 let me show  a pic 2011-10-16 01:16 aah 2011-10-16 01:19 DocScrutinizer: how the price could be reduced in some product like MM? 2011-10-16 01:20 DocScrutinizer: sorry for the tooo general question 2011-10-16 01:20 I'm not the business dude, but I think fist you have to look closely at where yur money goes right now 2011-10-16 01:20 i see that one thing looks constant for the run is SMT price 2011-10-16 01:21 I don't think leaving out chips makes much difference 2011-10-16 01:21 the best is to keep 1 unified product, and increase the quality, manufacturability (yield) and volume of that solution 2011-10-16 01:22 if anybody disagrees - go manufacture yourself, all files are open :-) like kristianpaul did with his case, for example 2011-10-16 01:22 *g* 2011-10-16 01:22 our product is already crazy cheap 2011-10-16 01:22 which is good 2011-10-16 01:22 and we will drive it down further 2011-10-16 01:22 but just above committing suicide 2011-10-16 01:23 there is a reason you will never find a new unusual product like this for such a price 2011-10-16 01:23 nobody is crazy enough and has the capabilities to do it 2011-10-16 01:23 for those that prefer to work with dev boards full of bugs that will never be fixed - go ahead :-) 2011-10-16 01:23 it's funny that over the years I noticed a dev board pattern 2011-10-16 01:24 the people that are saying "look this 19.99 USD subsidized dev board is so much better" are mostly the ones that have never bought a dev board or done anything with one 2011-10-16 01:24 whereas people who are regularly buying and using dev boards are *amazed* that M1 comes out at only 499 USD and happily buy one (I have such customers) 2011-10-16 01:24 interesting, eh? :-) 2011-10-16 01:25 so my focus is on making rc4 as good as possible now 2011-10-16 01:25 first the reset ic / nor corruption improvements, then other little things we learnt in rc3 2011-10-16 01:25 i donk think they remenber the word subsidized 2011-10-16 01:26 yield and manufacturability must go up 2011-10-16 01:26 this will help everybody later 2011-10-16 01:26 DocScrutinizer: http://wikisend.com/download/348752/M1_rc3_labled_u7u19u20.JPG 2011-10-16 01:26 'better' expansion header - yes please! 2011-10-16 01:26 upgrade to adv7181c 2011-10-16 01:26 and so on 2011-10-16 01:26 maybe leds for the ports 2011-10-16 01:26 maybe upgrade to dvi-i 2011-10-16 01:27 just full power improve everywhere ;-) 2011-10-16 01:27 kristianpaul: please help with specific ideas for better expansion header(s) 2011-10-16 01:27 Okay 2011-10-16 01:28 kristianpaul: sorry, I wouldn't know how to use that 2011-10-16 01:28 I do np :) 2011-10-16 01:29 (actually I probably could get it working, by downloading it, storing it to some temp dir, renaming it .JPG -> .jpg, then opening it in file browser 2011-10-16 01:29 ) 2011-10-16 01:29 ahh, i tought you mean about J21 ... 2011-10-16 01:31 DocScrutinizer: http://kristianpaul.org/~paul/tmp/M1_rc3_labled_u7u19u20.JPG 2011-10-16 01:31 seems he needs lower-case .jpg 2011-10-16 01:31 ah wait 2011-10-16 01:31 np 2011-10-16 01:31 already watching it 2011-10-16 01:31 DocScrutinizer: http://kristianpaul.org/~paul/tmp/M1_rc3_labled_u7u19u20.jpg 2011-10-16 01:32 as long as minme tipe isn't octet stream ;-D 2011-10-16 01:32 mime type 2011-10-16 01:33 post connector 2011-10-16 01:33 k 2011-10-16 01:33 pretty easy to extend 2011-10-16 01:35 if you leave out 2 posts, then the old plug will fit on subpart of new extended J21 2011-10-16 01:35 compatibility: check 2011-10-16 01:36 layouters will hate me 2011-10-16 01:37 OMFG what's that upper right? USB? 2011-10-16 01:37 Yes 2011-10-16 01:37 and those are meant to last? 2011-10-16 01:38 looks flimsy 2011-10-16 01:38 In the case i bet yes 2011-10-16 01:39 how about using standard dual USB breakout with post connector and ribbon cable? 2011-10-16 01:39 well, adds to BOM 2011-10-16 01:40 haha for the xtal 40° 2011-10-16 01:40 45° 2011-10-16 01:41 quite cool design :-) 2011-10-16 01:42 what are those funny little red arrow stickers? 2011-10-16 01:44 and what's that module lower left? 2011-10-16 01:46 must be a PSU 2011-10-16 01:46 yes 2011-10-16 01:50 http://www.ohwr.org/attachments/365/8b10b.png 2011-10-16 01:54 one tip from dirty every day experience: make your testpoints vias with the nice golden ring around the hole - WAY easier to place and *keep* a probe on such a via 2011-10-16 01:57 and just in case you're going to permanently contact such a testpad, you can use true thru-hole wiring instead of just soldering a wire on top of the pad (which has a certain tendency to come off when somebody pulls that wire a bit) 2011-10-16 01:58 if you use 1.2mm holes then there are even plugs that could plug in 2011-10-16 01:59 at least I think I've seen such plugs 2011-10-16 02:01 for J21 it seems possible to extend it to "north" quite a bit. To maybe 38 or 40 pins (minus the 2 you need to cut away to allow old 18pin connector to fit) 2011-10-16 02:02 wolfspraul: toldya you don't want me to look at it ;-D  Whoever is your layouter, will hate me forever for this suggestion 2011-10-16 02:05 kristianpaul: http://www.ohwr.org/attachments/365/8b10b.png puzzles me 2011-10-16 02:07 DocScrutinizer: http://www.ohwr.org/documents/36 2011-10-16 02:11 kristianpaul: well, nice. But that'S not related to the module lower left side labeled U11 if I can read that 2011-10-16 02:11 is it? 2011-10-16 02:13 nope, thats a regulator i think 2011-10-16 02:14 http://www.ti.com/lit/gpn/pth04000w 2011-10-16 02:16 that'S what I thought, PSU aka regulator 2011-10-16 02:18 I get a bit of headache seeing those connectors with massive force associated and consequently with screws to hold the component against housing, at more than one side of PCB: VGA and DMX 2011-10-16 02:20 screwing both to the case inevitably introduces mech tension to the PCB, even without somebody jogging the plugs in those receptacles 2011-10-16 02:22 aah wait, VGA has no case-mount 2011-10-16 02:23 though it probably better had 2011-10-16 03:53 wolfspraul: (WE#/CE0) i've tried WE#. does no harm, correct. may help a little. data is a still a bit foggy. 2011-10-16 03:56 zrafa: (CLK/CMD via MMC) great ! 2011-10-16 04:16 (exp bus) extension north is probably hard. must be a busy area. 2011-10-16 04:16 but yes, the rest of the surface is pretty much covered :) 2011-10-16 04:17 what i don't like so much about the header is that there's no peer to let an extension board to form a mechanical "bridge" 2011-10-16 04:17 wpwrak: my problem is the RON :) 2011-10-16 04:17 wpwrak: so far, the level of RON I drunk is okey to work yet 2011-10-16 04:17 wpwrak: but i have the bottle near 2011-10-16 04:18 and there is coca yet 2011-10-16 04:18 zrafa: ;-))) 2011-10-16 04:18 we will see how long 2011-10-16 04:18 I will have energy and patience for this task 2011-10-16 04:19 try increasing the coke to rum ratio. then you'll last longer :)) 2011-10-16 04:19 wpwrak: I have understood some important bits so I think that I did some advance at least 2011-10-16 04:19 kewl ! 2011-10-16 04:25 we can remove the J3 audio codec expansion header, I think 2011-10-16 04:25 wpwrak: do you want Adam to help with some design verification? 2011-10-16 04:25 or should he wait a little longer because it overlaps with your nor tests? 2011-10-16 04:25 Adam is still busy with rc3 2011-10-16 04:26 but at some point I want to move forward to rc4 with all resources I have 2011-10-16 04:26 hmm, i have to get him a labsw. he has a lot more boards to play with :) 2011-10-16 04:28 that's such a useful board, maybe we just make a small run :-) 2011-10-16 04:28 and give away to some of our trusted core qi hackers 2011-10-16 04:28 (rc4) i'm currently on the pull-ups. WE# looks safe (as expected) but i'm not sure if it helps or not. my test data shows some divergence - one run says it got ~20% better, the next says 50%. 2011-10-16 04:28 I want to accelerate 2011-10-16 04:28 so that's another idea 2011-10-16 04:28 quick labsw run 2011-10-16 04:29 to make up for the 50%, it has now blown up flickernoise :) 2011-10-16 04:29 so the next for you is to also try CE0 ? 2011-10-16 04:29 and the gate and 4.4v reset ic? 2011-10-16 04:30 yup, in that order 2011-10-16 04:30 I would just make all those mods and once and see whether the corruption is gone for good :-) 2011-10-16 04:31 the problem is that i still seem to have external factors. maybe i just need more cycles to exorcise them, but maybe not 2011-10-16 04:31 should we include leds for ports in rc4? 2011-10-16 04:31 Sebastien is traditionally a bit reluctant about leds 2011-10-16 04:31 ah ? how come ? 2011-10-16 04:31 and I don't know how many free fpga pins we actually have left 2011-10-16 04:32 a lot, i think :) 2011-10-16 04:32 I vaguely remember roh proposing something along those lines many moons ago 2011-10-16 04:32 see page 3 of the schematics 2011-10-16 04:32 roh suggested 4 leds in the corners, for illumination effects 2011-10-16 04:32 heh :) 2011-10-16 04:32 I am fine with all this, leds for ports, leds for corners, etc. as long as nobody feels the product is being ruined 2011-10-16 04:33 and if there are free pins in the fpga, its' probably better to move them somewhere rather than let them die under the bga 2011-10-16 04:33 not sure how constrained the board is with regard to the routing, though 2011-10-16 04:33 that's assumign there are no routing problems... 2011-10-16 04:33 sure, but first we need to define what we want 2011-10-16 04:34 another thing is the need of the metal sheet at the bottom side 2011-10-16 04:35 with every layout change and run we loose a chance to remove the need for it, assuming our tests are regression-safe 2011-10-16 04:35 (sheet) do you know why specifically it's needed ? 2011-10-16 04:35 sort of 2011-10-16 04:36 I stood right there when the test failed, so I can describe 2011-10-16 04:36 we put a thin large metal sheet on the test table 2011-10-16 04:36 then on top of that a plastic insulation layer 2011-10-16 04:36 on top of that we put the assembled M1 (in acrylic case) 2011-10-16 04:36 we let M1 run 2011-10-16 04:36 now we induce a 6kV discharge into the metal 2011-10-16 04:37 the metal sheet 2011-10-16 04:37 what happens is that there are some visual corruptions in the rendering 2011-10-16 04:37 after 2 or 3 such shots, m1 just freezes or goes dark 2011-10-16 04:37 if we turn the m1 upside down, the test passes 2011-10-16 04:38 funny :) 2011-10-16 04:38 so it's some field that goes through the insulation plastic and acrylic into the pcb 2011-10-16 04:38 if the distance is a bit more (such as when m1 is upside down), m1 keeps running 2011-10-16 04:38 but if the pcb is only maybe 1 cm or so away from the metal, maybe it corrupts memory 2011-10-16 04:39 memory corruption was Sebastien's wild guess from seeing the behavior 2011-10-16 04:39 the problem is to identify the 'sink' 2011-10-16 04:39 would be time consuming 2011-10-16 04:39 it may be hard to reproduce, too 2011-10-16 04:39 so we just added this metal sheet between acrylic and pcb, and indeed that fixes the problem 2011-10-16 04:39 no 2011-10-16 04:39 definitely reproducible 2011-10-16 04:39 easy 2011-10-16 04:39 4kV also shows it 2011-10-16 04:39 we tested this many times 2011-10-16 04:39 ah, good. 2011-10-16 04:40 this 6kV shot creates some field 2011-10-16 04:40 the field enters the pcb and corrupts maybe the memory 2011-10-16 04:40 the field gets a lot weaker with distance 2011-10-16 04:40 DocScrutinizer51 probably knows a lot about EMI :) 2011-10-16 04:40 yes, all that makes sense 2011-10-16 04:40 the way to fix this in the right way would be to find the exact 'sink', where the field/corruption enters 2011-10-16 04:41 but since we found the metal sheet workaround, we put that aside 2011-10-16 04:41 not sure how to fix it, though. perhaps just a continuous ground plane at the bottom would do the trick 2011-10-16 04:41 now, with every layout change we have a chance to try something 2011-10-16 04:41 if we are sort of sure we don't introduce regressions, there are almost no costs to that 2011-10-16 04:41 there are lots of ground planes already 2011-10-16 04:41 but I don't know the exact details of the planes, vias, etc. 2011-10-16 04:42 if we could remove the neet for the metal sheet, that would be a big improvement in terms of manufacturability and cost 2011-10-16 04:42 the bottom has many split planes 2011-10-16 04:42 so field goes into the comes out through the other. current flows between. 2011-10-16 04:43 is the metal sheet so expensive ? 2011-10-16 04:43 is it easy to make a change that might help 2011-10-16 04:43 or risky? 2011-10-16 04:43 it's very labor intensive 2011-10-16 04:43 and it looks bad too 2011-10-16 04:43 that metal sheet plus insulation layer alone is probably 30% of roh's work 2011-10-16 04:44 the next big thing are the buttons 2011-10-16 04:44 another 30% 2011-10-16 04:44 the entire rest is 40% of the work 2011-10-16 04:44 was that testing done after or before we shorted all those chokes ? 2011-10-16 04:44 all my guess, roh can feedback if I'm wrong 2011-10-16 04:44 shorted what? 2011-10-16 04:45 maybe it would also help if we moved some of the stuff on the bottom side to the top? 2011-10-16 04:45 (buttons) ah, let me show you something :) http://downloads.qi-hardware.com/people/werner/tmp/m1butwood.jpg 2011-10-16 04:45 although there's probably a reason it's there... 2011-10-16 04:45 yes I saw that pic already :-) 2011-10-16 04:45 (shortened) the Ls that "connected" ground planes. 2011-10-16 04:45 (but left all the spikes to go through the chips, making them rather unhappy) 2011-10-16 04:45 you mean L3 and L19 2011-10-16 04:46 testing was done before that 2011-10-16 04:46 yes, probably. don't remember the numbers. 2011-10-16 04:46 if Joerg has any ideas what low-risk improvements to try about this ESD problem, great 2011-10-16 04:46 could be that L3 and L19 fixed that issue as well 2011-10-16 04:46 that would be great 2011-10-16 04:47 but I won't hold my breadth, this 6kV thing looked like a bomb 2011-10-16 04:48 can those 2 small fixes really help? I don't know 2011-10-16 04:48 (buttons) i'm a little concerned about bringing ESD into the box, otherwise i'd cut them from aluminium. that would look nice. (would take hours, though) 2011-10-16 04:48 these 2 small fixes aren't so small when you consider what they do ;-) 2011-10-16 04:49 we have a relatively good feeling saying that the ESD shot created a memory corruption 2011-10-16 04:49 it was a software problem that eventually made it freeze 2011-10-16 04:49 that was our 'feeling' after repeating this a number of times 2011-10-16 04:49 before you basically had two antennas (regarding EMI) and a chip in between. now it's two antennas and a wire. and the chip on the side, happily staying out of the mess. 2011-10-16 04:50 could be. i don't know what things depend on these two chips. i think sebastien said one provides an important clock 2011-10-16 04:50 if I remember correctly, with 4kV it showed the problem only sometimes, maybe it took 2-3 shots 2011-10-16 04:51 at 6kV almost every shot brought it down a little more ;-) 2011-10-16 04:51 and at 8kV there was no hope 2011-10-16 04:51 so if that gets upset, who knows what can happen. we already know that it can freeze the system. 2011-10-16 04:52 I think the test requires 4kV and 6kV is optional, or something like that 2011-10-16 04:52 there are ways to explain oneself out of this, but that was not our goal 2011-10-16 04:53 if it's easy to do, i'd take a shot with the shorted Ls. they address quite specifically this problem domain 2011-10-16 04:53 anyway I just wanted to mention it again 2011-10-16 04:53 every relayout and run is a chance to improve this, as long as we are sure not to introduce regressions 2011-10-16 04:53 Sebastien would have to go back to the lab 2011-10-16 04:53 easy - yes, sort of. but still work. 2011-10-16 04:54 cost small, if any. that guy is very relaxed. 2011-10-16 04:54 but I cannot help with this, the lab is in Berlin 2011-10-16 04:54 how much does one of these esd guns cost actually? 2011-10-16 04:54 that particular test is very low tech 2011-10-16 04:54 maybe sebastien can pay him a visit ? 2011-10-16 04:54 so unless there is a shortage of knowledge, it's easy to play with this at home :-) 2011-10-16 04:55 yes Sebastien could 2011-10-16 04:55 if he feels this is an important enough thing to work on 2011-10-16 04:55 maybe such a gun can be bought for 100 USD or so? 2011-10-16 04:56 searching ... "ESD Awareness Training" hehe ;-) 2011-10-16 04:56 then we need to document the test setup a little to not electrocute ourselves, then we can play 2011-10-16 04:56 hmm, nothing under "esd *" from the usual suspects 2011-10-16 04:57 the "now i have the gun. let's see if i can upset *this*." phase will be expensive, though :) 2011-10-16 04:57 not sure 2011-10-16 04:58 there are different levels of 'pass' 2011-10-16 04:58 the highest level is that it passes without any issues or interruption 2011-10-16 04:58 even then you have different strengths of shocks 2011-10-16 04:58 at some point everything goes down 2011-10-16 04:58 the second level is that it keeps running, but with problem 2011-10-16 04:58 third level is that it shuts off or reboots 2011-10-16 04:58 fourth level would be permanent damage, I guess :-) 2011-10-16 04:58 something like taht 2011-10-16 04:59 manufacturers have, as with many of those things, a gree leeway in how they intepret all this and how well they actually want to engineer their products 2011-10-16 04:59 since everything will fail at some point 2011-10-16 04:59 great leeway 2011-10-16 05:00 we could have left out that metal sheet and nobody would have noticed or cared or it most likely would ever have mattered 2011-10-16 05:00 mhm, and a 75kV electroshocker can easily take out of service every phonebooth and cigarette machine 2011-10-16 05:00 so when you have such a gun, you start with 2kV 2011-10-16 05:00 can test your household stuff a little :-) 2011-10-16 05:00 I bet [75kV] 2011-10-16 05:01 DocScrutinizer: did you read up on the test above? 2011-10-16 05:01 any ideas what we might improve in the board? 2011-10-16 05:01 improve for what? which test? 2011-10-16 05:02 phew :-) 2011-10-16 05:02 (test your household stuff a little) yeah, that;s what i meant with the expensive part ;-) 2011-10-16 05:02 just above, a few lines 2011-10-16 05:02 wpwrak: yes but you start with 1kv, 2kv 2011-10-16 05:02 and then you slowly go up 2011-10-16 05:02 and as you go up, you will see when stuff starts failing 2011-10-16 05:02 I doubt the very first thing you see is a permanent damage 2011-10-16 05:02 ESD test? weardll, dunno the bo 2011-10-16 05:02 grr 2011-10-16 05:02 DocScrutinizer: I describe it again 2011-10-16 05:03 ESD test? well, dunno the board 2011-10-16 05:03 put metal sheet on table, put plastic insulation on top 2011-10-16 05:03 then Milkymist One, assembled in acrylic case, on top of that 2011-10-16 05:03 shoot 6kV into metal on table 2011-10-16 05:03 what we observed looked like a memory corruption 2011-10-16 05:03 m1 kept running, but with strange visuals 2011-10-16 05:03 when we turned the m1 upside down, it was stable 2011-10-16 05:03 not exactly a surprise 2011-10-16 05:04 in upside down, the pcb is about 3 cm further away from the metal that gets the shock 2011-10-16 05:04 when we put a metal insulation layer below the pcb, it was stable also with the pcb on the bottom 2011-10-16 05:04 so the order then was 2011-10-16 05:04 jep, or like 8 times further, I guess 2011-10-16 05:04 1. metal on table 2011-10-16 05:04 2. plastic insulation 2011-10-16 05:04 3. acrylic 2011-10-16 05:04 4. metal sheet inside case 2011-10-16 05:04 5. pcb 2011-10-16 05:05 the pcb was < 1 cm away from the metal that got the shock 2011-10-16 05:05 that was stable 2011-10-16 05:05 but when we remove #4, we get what looks like memory corruption 2011-10-16 05:05 yup 2011-10-16 05:05 for rc3, we kept the metal insulation layer inside the case, but it was a lot of hard work 2011-10-16 05:06 so we are thinking what long shots we can try in rc4, something with low risk of bad side-effects, to improve this 2011-10-16 05:06 DocScrutinizer: that was also before we shorted those chokes/beads connecting certain ground areas. so i wouldn't be surprised if this alone could change the odds of the ESD problem still existing. 2011-10-16 05:06 well, improve the metal sheet design to reduce work with it 2011-10-16 05:06 make a metal case ;-) 2011-10-16 05:07 "improve the metal sheet design" ? 2011-10-16 05:07 it's a lot of work no matter which way you turn it 2011-10-16 05:07 and only needed because the pcb itself is not designed to keep the esd impact away 2011-10-16 05:07 which is most likely possible in some way 2011-10-16 05:07 why is it so much work ? that's what i don't quite get 2011-10-16 05:08 because it is 2011-10-16 05:08 manual labor 2011-10-16 05:08 A) 0.6cm vs 3.6cm may well make the difference between direct spark impact to some chip and the discharge going to the cable or desk's steel frame in the top-down case 2011-10-16 05:08 not just running a software loop a couple times more :-) 2011-10-16 05:08 metal needs to be sourced, cut 2011-10-16 05:08 holes need to be drilled 2011-10-16 05:09 insulation layer needs to be glued on it 2011-10-16 05:09 that thing along was 30% of the workload for the entire rc3 cases 2011-10-16 05:09 alone 2011-10-16 05:09 and it's completely unnecessary 2011-10-16 05:09 no, it's not 2011-10-16 05:10 a metal shielding against ESD is mandatory quite frequently 2011-10-16 05:10 you think there is no way to get rid of it? 2011-10-16 05:10 probably not 2011-10-16 05:12 my guess is that it's a kludge only needed because we combine a lust of meeting standards with lack of resources :-) 2011-10-16 05:12 ESD tests are assuming discharge to a GND level metal or other conductor "shield" of any kind. No PCB / circuit can be built in a way such that ESD in middle of the board won't directly impact on any arbitrary chip 2011-10-16 05:12 no 2011-10-16 05:12 not middle of the board 2011-10-16 05:13 I described the test setup already twice now :-) 2011-10-16 05:13 isn't the source metal plate in parallel to the PCB? 2011-10-16 05:13 yes 2011-10-16 05:13 so discharge can hit middle of PCB 2011-10-16 05:13 the spark was applied to the side of the metal plate 2011-10-16 05:14 in real life even more likely to happen 2011-10-16 05:14 that's irrelevant 2011-10-16 05:15 you could replace the metal sheet inside by a wire going 5 times zickzack across the plastic case bottom 2011-10-16 05:15 faraday cage 2011-10-16 05:15 or more like lightning protector 2011-10-16 05:16 get 5mm alu sticky tape on endless reel 2011-10-16 05:16 ok I am pretty sure we could make layout changes to the pcb that would let us pass this test 2011-10-16 05:17 you can't, basically 2011-10-16 05:17 add another layer to the pcb to just move the metal to that layer 2011-10-16 05:18 ? 2011-10-16 05:19 no? 2011-10-16 05:19 metal layer is metal layer 2011-10-16 05:19 the problem is your chips aren't *under* that layer 2011-10-16 05:20 yes they are above 2011-10-16 05:20 just like with the metal sheet we added now 2011-10-16 05:21 you don't need a metal sheet, you just need a wire at same location 2011-10-16 05:22 alright we don't get many practical ideas out now :-) 2011-10-16 05:23 connect that wire to central GND point (usually minus of power supply, sometimes EE decides to have GND of input as central GND point) 2011-10-16 05:23 maybe someone buys a gun, then we can more easily play with it 2011-10-16 05:23 and maybe we can find the area of the board where it enters, and a simple metallic tape at that location may be enough? 2011-10-16 05:23 I don't know 2011-10-16 05:23 run a gnd trace all along the sides of your PCB 2011-10-16 05:23 I'm sure there are better ways to improve it than what we have in rc3 2011-10-16 05:24 [gnd trace along sides] ok, we can ask around and see whether someone thinks this is a bad idea 2011-10-16 05:25 the point where it enters is irrelevant if you catch the discharge spark halfway at the location where your metal sheet is now 2011-10-16 05:25 we have a lot of space on the bottom. actually I'm wondering why we can't move all components to the top. 2011-10-16 05:25 spark? 2011-10-16 05:26 the spark enters the metal sheet far away, say 30cm or so away from the M1 2011-10-16 05:26 wolfspraul: what is your take on what actually happens to the electrons after they entered the source metal plate ? 2011-10-16 05:26 my definition of 'spark' may be a little simplistic, I thought it's just the thing you can see... 2011-10-16 05:26 sure the metal conducts 2011-10-16 05:27 and then there's the plastic insulation on top of it 2011-10-16 05:28 it will go to GND one way or another 2011-10-16 05:28 one way was directly to some metal of the desk it sits on 2011-10-16 05:29 another was to cable (e.g vga, or power, or usb whatever) straight thru the cable's isolation 2011-10-16 05:29 yet another was straight thru the layers 2) and 3) missing 4) metal sheet into a chip on 5) PCB 2011-10-16 05:30 wolfspraul: (sheet) ah, you built it from scratch. i see. i though you got it already pre-fabbed, from one of your famous corner shops :) 2011-10-16 05:31 if it doesn't do a real discharge, then it induces capacitive interference into the most protruding parts of PCB, even thru the layers 2 and 3 2011-10-16 05:31 ...unless you got either a metal sheet or a few wires there to form a faraday cage 2011-10-16 05:31 perhaps replacing the M1's bottom acrylic with metal would help. a tad messy to produce in low volume, though. 2011-10-16 05:31 maybe kristianpaul can find a cheap place with a CNC mill :) 2011-10-16 05:32 no no 2011-10-16 05:32 those are separate solutions 2011-10-16 05:32 of course we can build a faraday cage 2011-10-16 05:32 we can build a metal case 2011-10-16 05:32 people use copper spray on the inside of plastic parts 2011-10-16 05:32 and so on 2011-10-16 05:32 but that is not what I am after right now 2011-10-16 05:32 I am trying to design the pcb better 2011-10-16 05:32 probably two stripes of metals sticky tape across the diagonals of the arcrylic wil suffice if you connect them to GND 2011-10-16 05:32 or 'as good as possible' 2011-10-16 05:32 that would be a partial metal case - just change the bottom plate, keep the rest of the concept 2011-10-16 05:33 because from the feedback we got from the testing guy, he thinks this can definitely be fixed inside the pcb, provided enough resources are thrown at that 2011-10-16 05:33 if you want a quick fix, see if it's already fixed :) 2011-10-16 05:33 just think about any modern smartphone, how thin they are, how much stuff is inside - how do they pass those tests? 2011-10-16 05:33 our problem if anything are our minuscule resources 2011-10-16 05:33 DocScrutinizer: do you know how much such ESD guns / ESD simulators cost ? 2011-10-16 05:33 we cannot just throw 100k USD research money at this to make it 'go away' 2011-10-16 05:33 you can't design PCB so much better that no bad effects will occur to chips directly, no matter if they are on bottom or top of PCB 2011-10-16 05:34 well I dout we can say our pcb right now is 'perfect' 2011-10-16 05:34 wpwrak: no, but I guess they are rather cheap 2011-10-16 05:34 especially when you haven't looked at it in detail yet (not saying you should, just pointing out a hole in your logic) 2011-10-16 05:34 my initial point was innocent 2011-10-16 05:34 it's basically just a capacitor that gets charged to a defined voltage 2011-10-16 05:35 I wanted to remind myself and others that every new run is a chance to get rid of the need of the metal sheet 2011-10-16 05:35 which would make roh happy :-) 2011-10-16 05:35 do you actually need the isolation on the metal sheet ? 2011-10-16 05:35 that's to avoid that the metal bends and shorts something on the bottom side of the pcb 2011-10-16 05:36 wolfspraul: we for sure can improve a few things on PCB, but that won't solve the problem, just reduce it 2011-10-16 05:36 especially after someone unassembles and reassembles the case 2011-10-16 05:36 yes .. but is that likely to happen ? 2011-10-16 05:36 reduce it may be enough to pass the test 2011-10-16 05:36 no it's not likely to happen 2011-10-16 05:36 okay, good 2011-10-16 05:36 we could have left out the entire metal sheet and just bend the rules like 99% of other commercial companies would have :-) 2011-10-16 05:36 and 100% of Chinese 2011-10-16 05:36 maybe that's why they are so successful :-) 2011-10-16 05:37 the right thing to do is to remember this thing with every run, and re-test once in a while, and maybe find a cheap fix that lifts us above the testing criteria 2011-10-16 05:37 then everything is 'perfect' 2011-10-16 05:37 and the metal sheet can be removed 2011-10-16 05:38 it's a waste of money and resources and distraction anyway 2011-10-16 05:38 another suggestion: place some posts on gndplane that protrude way further than the sensitive parts next to them 2011-10-16 05:38 can you translate it down to my dumbness level? 2011-10-16 05:39 first idea - run a gnd trace around the outline of the board 2011-10-16 05:39 right? 2011-10-16 05:39 bottom side I guess? or bottom and top? 2011-10-16 05:39 right 2011-10-16 05:39 if you want to remove it and are worried about being able to sleep at night, i'd just test M1rc3. two major offenders have already been fixed there, and a search for more hasn't turned up anything else that looks suspicious 2011-10-16 05:40 bottom and top, and connect to real GND only in one spot, which is the central GND spot 2011-10-16 05:41 yup, there've been those incredibly stupid chokes in GND 2011-10-16 05:41 DocScrutinizer: GND around the PCB ... how does this mix with connectors that have metal at the edge ? 2011-10-16 05:41 no worries I can sleep great 2011-10-16 05:41 those are like building a parabolic dish for ESD 2011-10-16 05:41 I think one reason for the closedness in the hardware industry is that they really depend on hiding a lot of stuff :-) 2011-10-16 05:41 (-:C 2011-10-16 05:42 wolfspraul: you've heard it ;) 2011-10-16 05:42 we have this sadistic mix of wanting to comply perfectly, even with idiotic laws and regulations that nobody follows, combined with a total lack of resources to follow 2011-10-16 05:42 that combination leads to being stuck 2011-10-16 05:42 an ousider might call it stupid 2011-10-16 05:42 all Chinese will call it stupid 2011-10-16 05:42 :-) 2011-10-16 05:42 i think they quickest way to get rid of the metal sheet is to just test again. the problem may very well have retreated beyond safe limits by now 2011-10-16 05:42 all the rest is good design advice, of course 2011-10-16 05:43 this is actually a quality level that makes sense, I'm just saying in general we do have this mix sometimes 2011-10-16 05:43 "hey, I have found this law here, look, we have to do this and that" 2011-10-16 05:43 wpwrak: mix? 2011-10-16 05:43 then I ask around the industry, and nobody even knows the laws, and everybody is busy couting their profits and paying taxes and bribes 2011-10-16 05:43 just kidding 2011-10-16 05:43 back to making M1 the perfect ESD machine... 2011-10-16 05:44 DocScrutinizer: if there's a connector with metal at the edge that doesn't go to "common ground". how would that fit with the "ground around the pcb" rule ? 2011-10-16 05:44 maybe the answer is "the connector should go to common ground" :) 2011-10-16 05:44 errr 2011-10-16 05:44 hmm 2011-10-16 05:44 what does this translate to exactly on m1 then 2011-10-16 05:45 maybe we even have that already? 2011-10-16 05:45 and what about those "posts on gndplane that protrude further than the sensitive parts" 2011-10-16 05:45 (posts) lightning rods :) 2011-10-16 05:46 either you have a separate shielding which goes to spark catcher, or you got just one GND (like on cinch) then it goes to analog GND and NOT spark catcher 2011-10-16 05:46 (have that already) yes, maybe. now that the split ground planes have grown together again, we may indeed have that already 2011-10-16 05:47 (lightning rod) yeah, or simply electrolytic capacitors for example 2011-10-16 05:47 the aluminium case is on - usually? 2011-10-16 05:47 on minus* 2011-10-16 05:47 no aluminum case 2011-10-16 05:47 acrylic case 2011-10-16 05:48 electrolyt capacitors have no acrylic case ;-D 2011-10-16 05:48 ah sorry, lost the context 2011-10-16 05:48 wolfspraul: the whole point is to have the most protruding conducting parts be GND level 2011-10-16 05:49 ok 2011-10-16 05:49 but I don't know what that translates to in the m1 pcb :-) 2011-10-16 05:49 and unfortunately the layout files are in Altium format still 2011-10-16 05:49 that would actually be the feet 2011-10-16 05:49 so hard to quickly converge around some specific small ideas now 2011-10-16 05:50 yes, kicad when ? ;-) 2011-10-16 05:50 looking on an arbitrary PCB next to me I see most protruding parts being xtal, capacitors, a huge choke witj siferrite core 2011-10-16 05:51 we can move to kicad, I'm super interested in that, but... the problem is once we do that we loose the ability to work with our layout house 2011-10-16 05:52 DocScrutinizer: this is what the bottom looks like http://downloads.qi-hardware.com/people/werner/m1/tmp/back.png 2011-10-16 05:52 ah, the layout is outsourced ? 2011-10-16 05:52 errr 2011-10-16 05:52 a photo of a real PCB would help better 2011-10-16 05:55 wolfspraul: one thing that may help with interference hardening is to move long traces traces to an inside layer 2011-10-16 05:56 e.g., the SDRAM address lines (those with the R7x and R8x resistors) 2011-10-16 05:57 on the other side of the FPGA, there are also what's probably NOR lines with a similar pattern 2011-10-16 05:58 interesting. the M1 schematics don't mention what value the series resistors of the SDRAM have 2011-10-16 05:58 wpwrak: layout outsourced sounds so draconian 2011-10-16 05:58 I think we have moved way past that 2011-10-16 05:59 the M1 electrical pcb files are continuously in Altium format, and yes, we have hired outside consultants to help us with those files, layout, review, give advice, etc. 2011-10-16 05:59 there are 2 layout personnel that by now are relatively familiar with the board's layout 2011-10-16 06:00 if we move to kicad, we loose the ability to get their feedback 2011-10-16 06:00 so I'm hesitating still 2011-10-16 06:01 can we import gerber files into kicad to transition the layout? 2011-10-16 06:02 the gerbers are probably available for download somewhere, since we put all files online and they have been sent to the pcb and/or smt fabs 2011-10-16 06:03 yes, we have the gerbers. not sure it they're a nice way to get started, though 2011-10-16 06:03 for example the planned change from vga to dvi-i connector 2011-10-16 06:03 e.g., you'd have difficulties making things "snap" 2011-10-16 06:03 especially if we go dual-link, we have a lot of new wires 2011-10-16 06:03 that would be done by the same layout people as before, using the Altium files 2011-10-16 06:04 Anson Lin and Vera Cheng 2011-10-16 06:05 trying to convert them to KiCad makes no sense, that will cost us more than not asking them to help at all 2011-10-16 06:05 ;-) 2011-10-16 06:05 it's not something you do in a weekend anyway 2011-10-16 06:05 yes we just have to be realistic here and choose the best path forward for the product 2011-10-16 06:05 you also need to update your components libs, footprints, etc. 2011-10-16 06:05 everything stays 100% open anyway 2011-10-16 06:05 the files 2011-10-16 06:06 even if they are in a bad format that makes our style of collaboration difficult (read: that will be replaced sooner or later, especially if we are successful) 2011-10-16 06:06 so... 2011-10-16 06:06 do we have some actionable rc4 esd ideas now? 2011-10-16 06:06 I'm still not 100% clear 2011-10-16 06:07 I can point Adam to this chat who can in turn point Anson and Vera to it 2011-10-16 06:07 most likely nothing will happen then :-) 2011-10-16 06:07 a smoother ramp-up would be a Ya done in kicad. build a larger kicad-savvy group in qi-hw. then M2 wouldn't be so hard either. 2011-10-16 06:07 yes but we are talking about rc4 now and I want to upgrade it with all the nice things we learnt in rc3 2011-10-16 06:07 M1 rc4 2011-10-16 06:07 the esd issue just came back to my mind 2011-10-16 06:08 since I think if we are lucky we can get rid of the metal sheet without much effort 2011-10-16 06:08 one thing that bothers me with kicad is that there's this major change to all the file formats hanging in the air. it's really have that past us already. that thing's been in the air for something like 1-2 years by now 2011-10-16 06:08 with some luck... 2011-10-16 06:09 DocScrutinizer: if you just put isolated metal tape on the PCB over some critical traces, without making an effort of grounding it, it should also help to keep the field away, no ? 2011-10-16 06:10 a lil bit, depends on how much it's coupling capacitively to GND vs to trace 2011-10-16 06:11 worst case thing get worse ;-P 2011-10-16 06:13 wolfspraul: here's your ESD gun: http://www.edn.com/archives/1996/091296/graph/19di1fg1.htm 2011-10-16 06:13 more details: http://www.edn.com/archives/1996/091296/19di1.htm#fig1 2011-10-16 06:15 DocScrutinizer: yeah, the area should be considerably larger than the trace. otherwise you'd indeed just have added one more trouble amplifier ;-) 2011-10-16 06:19 seems that ESD guns aren't that cheap. http://www.testequip.com/sale/details/HAE0002.html   USD 7000 2011-10-16 06:20 there should be simpler ones, though. hard to google. 2011-10-16 06:27 DocScrutinizer: thanks a lot for your feedback! 2011-10-16 06:28 we have been a little weak and unsystematic in the past in translating your feedback into actual improvements in the runs, but I believe a few things have made it, and we may become more systematic over time ;-) 2011-10-16 06:28 hmm. there are interesting "related" products: http://www.zapper.com/html/ultra_small_blood_zapper.html 2011-10-16 06:29 "blood electrifier" damn. i need that :) 2011-10-16 06:31 yeah, seems that the ESD simulators you can actually find a price for are all quite expensive 2011-10-16 06:32 probably > 50% going into insurance :) 2011-10-16 06:36 why that expensive? 2011-10-16 06:36 with my China brain I'd give it 100 USD 2011-10-16 06:36 (small) electrocution risk included, of course 2011-10-16 06:38 I shall add it to my sourcing list, next time I'm near a market... :-) 2011-10-16 06:38 you should visit the market and see what you find. 2011-10-16 06:38 exactly ;-) 2011-10-16 06:40 but, and I am not kidding you. if I would buy one in China I would only operate it wearing some insulating glove that I am sure is sourced and ideally made from a foreign brand 2011-10-16 06:41 I wouldn't value my own life at 10 USD or so, fair Chinese market value 2011-10-16 06:41 (gloves) ;-))) 2011-10-16 06:41 just judging from all the most basic things that are falling apart in my household 2011-10-16 06:41 amazing how many things one can get wrong 2011-10-16 06:41 really 2011-10-16 06:42 how many electrical fires did you have to put out so far ?:) 2011-10-16 06:42 so yes, seriously. only with a glove I can trust, sourced from a foreign brand. I am not kidding. 2011-10-16 06:42 well 2011-10-16 06:42 they know each other 2011-10-16 06:42 so the glove will be more expensive than the ESD critter ;-) 2011-10-16 06:42 so when I turn on the mini oven and microwave together, the fuse jumps out 2011-10-16 06:42 that's a good start :) 2011-10-16 06:43 because the cabling and pretty much everything is typically so crappy, you work with small fuses just in case 2011-10-16 06:43 hopefully the fuses are made in Japan 2011-10-16 06:43 I am sure one can get that wrong too 2011-10-16 06:43 fine but I would insist on such a glove 2011-10-16 06:43 using a made in China ESD gun 2011-10-16 06:44 so not 100% adapted to chinese standards yet ;-) 2011-10-16 06:44 I take enough risks even that way, it could explode etc. 2011-10-16 06:44 best would be to hire a Chinese proxy worker 2011-10-16 06:44 remote hands, literally 2011-10-16 06:44 :-) 2011-10-16 06:44 ;-)) 2011-10-16 13:22 wolfspraul: I fail to imagine a glove tested for 20kV isolation (20 as you need a safety margin, you dunno if that 8kV tester really works at 8kV - which is btw the most expensive thing of such a device: regulation of the high voltage to an exact value) 2011-10-16 13:23 idly ponders to suggest revamping a 20ct piezo gas lighter 2011-10-16 13:24 DocScrutinizer: yes, thanks for the notice :-) 2011-10-16 13:24 probably better meets the specs than a chinese ESD gun ;-D 2011-10-16 13:25 maybe there really are no Chinese ESD guns, and that's why the foreign ones are still expensive 2011-10-16 13:25 even the Chinese may be unable to sustain the personnel losses from using their own ESD guns :-) 2011-10-16 13:25 fair assumption 2011-10-16 13:26 I wouldn't be surprised the least if that were actually the case 2011-10-16 13:26 I have made stranger realizations in China... 2011-10-16 13:26 also there's simply no market for such a device 2011-10-16 13:26 because nobody cares about ESD? :-) 2011-10-16 13:26 he he 2011-10-16 13:26 we become the cynicist club here... 2011-10-16 13:27 it's not that bad - I will keep my eyes open 2011-10-16 13:27 as chinese don't care at all about ESD tests, and export won't be interested for know reasons 2011-10-16 13:27 actually in Taiwan I've heard taking those shots is not that bad 2011-10-16 13:27 they use it as some kind of mutprobe 2011-10-16 13:28 when you get a strong esd discharge at home, how strong is that compared to a 4kV shot from a gun? don't know... 2011-10-16 13:29 of course if something is wrong with the gun, all bets are off, I guess :-) 2011-10-16 13:29 probably quite similar, as those 4kV got picked to simulate exactly that 2011-10-16 13:30 there's even the HBM, human body model. taletelling, no? 2011-10-16 13:33 http://en.wikipedia.org/wiki/Electrostatic_discharge#Simulation_and_testing_for_electronic_devices   http://en.wikipedia.org/wiki/Human_body_model  >>In both JS-001-2010 and MIL-STD-883G the charged human body is modeled by a 100 pF capacitor and a 1500 ohm discharging resistance. During testing, the fully charged capacitor is discharged through the resistor connected in series to the device under test.<< 100pF isn't really lethal 2011-10-16 13:33 even at 8kV 2011-10-16 13:34 the PSU will be ridiculously weak as that's cheaper, so no danger to get more power from that side either 2011-10-16 13:34 HBM and MM frequently used to test ESD 2011-10-16 13:35 http://en.wikipedia.org/wiki/Machine_model 2011-10-16 13:35 duh, scratch that last link 2011-10-16 13:39 >>Guidelines and requirements are given for [...] types and points of discharge on the "victim" product...<< 2011-10-16 13:40 all this just to get a set of test(-conditions) that most closely simulates your everyday inhouse synthetic carpet ESD event when grabbing the device 2011-10-16 13:41 yes 2011-10-16 13:43 so, given a piezo spark unit from a lighter feels much the same like everyday ESD events, and also discharge gap length indicates voltage is ~in right ballpark, you probably are just fine to actually revamp a lighter for first reproducible tests 2011-10-16 13:44 additional benefit: proven small risk of auto-electrocution 2011-10-16 13:44 :-) 2011-10-16 13:51 wolfspraul: could you point me to a set of photos of the bottom side of an assembled M1 and the inside of the bottom case? Latter one preferably with and *without* the metal sheet 2011-10-16 13:54 ooh, already getting late over there :-D 2011-10-16 14:04 DocScrutinizer: ok, some pictures that clarify the overall mechanical construction are here http://en.qi-hardware.com/wiki/Milkymist_One_accessories#packing_instructions 2011-10-16 14:05 without components 2011-10-16 14:05 http://en.qi-hardware.com/wiki/File:Milkymist_one_rc3_bare_pcb_bottom.jpg 2011-10-16 14:05 http://en.qi-hardware.com/wiki/File:Milkymist_one_rc3_bare_pcb_top.jpg 2011-10-16 14:05 wolfspraul: thanks :-D 2011-10-16 14:06 very nice, the case bottom is way simpler to think about alternatives to your metal sheet than I thought 2011-10-16 14:07 with components I only have some unfocused shots http://en.qi-hardware.com/wiki/File:M1_rc3_hw_fix2_bottom.JPG 2011-10-16 14:07 instead of using the metal sheet I suggest using 5mm wide endless aluminium sticky tape and attach two stripes across the diagonals 2011-10-16 14:07 (that wire is not there anymore now) 2011-10-16 14:08 http://en.qi-hardware.com/wiki/File:M1_rc3_hw_fix2_top.JPG 2011-10-16 14:08 you mean like a big 'X' across the entire bottom? 2011-10-16 14:09 that certainly would look pretty cool too :-) 2011-10-16 14:09 but will it work? 2011-10-16 14:09 will work way better than nothing 2011-10-16 14:09 the ends of the 'X' should be connected to the 4 spacers? 2011-10-16 14:09 yes 2011-10-16 14:09 well, definitely an interesting new idea 2011-10-16 14:10 estimated work time: ~60s per unit 2011-10-16 14:10 why will that work as well as a metal sheet covering the whole surface? 2011-10-16 14:10 faraday cage principle 2011-10-16 14:10 my naive thinking would be that a lot of pcb ground is not covered by another layer of metal then, no? 2011-10-16 14:11 I mean "pcb space" (ground is ambiguous here) 2011-10-16 14:11 ah ok [faraday] 2011-10-16 14:11 definitely worth a try 2011-10-16 14:13 wolfspraul: possibly you should contact each of the 2 stripes only to one spacer, to avoid GND loops 2011-10-16 14:15 should they connect to each other in the middle? 2011-10-16 14:16 will get separated by the glue, and that's OK'ish 2011-10-16 14:16 what's better? for the aluminum to make contact in the middle of the 'X', or to be isolated? 2011-10-16 14:16 it's non-critical but better they don't contact - again for GND-loops 2011-10-16 14:17 ok. and only one end connect to the spacer 2011-10-16 14:17 so the "isolation" provided by the glue was already planned in 2011-10-16 14:17 maybe make it just stop right before the spacer on the other side? 2011-10-16 14:17 yes, only one end to spacer 2011-10-16 14:17 yes 2011-10-16 14:17 I mean make it a little shorter to not reach all the way to the spacer on the other side 2011-10-16 14:17 ok 2011-10-16 14:18 got it 2011-10-16 14:18 :-) 2011-10-16 14:19 of course you may go fancy and create nice patterns with a (then uncut) tape forming e.g "M1" or "JR" ;-D 2011-10-16 14:20 but it needs to connect to a spacer? 2011-10-16 14:20 1 enough? 2011-10-16 14:20 then run one stripe from pattern to one spacer 2011-10-16 14:20 yes 2011-10-16 14:25 interesting idea 2011-10-16 14:25 now we only need an ESD gun somewhere then we can easily test :-) 2011-10-16 14:25 actually splicing alias contacting cut tape ends may be a bit difficult, so better not cut it at all when doing that pattern fancy 2011-10-16 14:25 nah, just X will do 2011-10-16 14:26 yep, think so 2011-10-16 14:26 if that worked, it would be a big improvement over the insulated metal sheet 2011-10-16 14:26 ok thanks a lot! 2011-10-16 14:26 yw 2011-10-16 14:26 like I said we still have other old feedback from you in the pipeline 2011-10-16 14:26 remove this that 2011-10-16 14:26 don't know where the list is right now and waht is done and not done 2011-10-16 14:26 will study :-) 2011-10-16 14:27 ah yes, there's some here http://en.qi-hardware.com/wiki/Milkymist_One_RC3_Known_Issues 2011-10-16 14:29 :nod: 2011-10-16 14:30 the chanlog should have it all 2011-10-16 14:34 they go even up to 40 kV :) http://www.professionalequipment.com/guide-to-electrician-safety-gloves/articles/ 2011-10-16 14:36 not too pricy either. class 2 for 20 kV peak: http://www.lonestarsafety.com/index.aspx?Command=GroupInfo&GroupID=11576 2011-10-16 14:37 class 4 costs a little more: http://www.highvoltagesupplies.com/store/product/class-4-insulating-gloves-1115.cfm 2011-10-16 14:37 but glove + chinese ESD tester would still be an order of magnitude cheaper than a proper ESD tester :) 2011-10-16 14:37 wpwrak: I realized something thinking about labsw & the led driver board - both are power supplies :-) 2011-10-16 14:38 right? 2011-10-16 14:38 I know it's a pretty crude way to start thinking, but that was my realization... 2011-10-16 14:41 The build was successfull, see images here: http://fidelio.qi-hardware.com/~xiangfu/compile-log/openwrt-xburst.full_system-10152011-1004/ 2011-10-16 14:44 the spacers have some fancy grounding ;-) into adjacent split grounds. i wonder if this is really such a good idea ... 2011-10-16 14:45 (labsw) there's nothing power supply in there. all it does it switch ;-) 2011-10-16 14:45 s/does it/does is/ 2011-10-16 14:45 and it switches slowly 2011-10-16 14:46 realized that i''ll have trouble sleeping when the power-cycling tests are done. i'll miss the clicking of the relays. 2011-10-16 14:46 s/realized/realizes/ 2011-10-16 14:55 wolfspraul: ah yes, regarding doing the modifications all together or one at a time, there's that problem of just driving the corruption out of the detection range vs. solving its cause 2011-10-16 14:56 if each change makes it a little less likely, i may very well have a run of 10'000 good cycles, but it's still there 2011-10-16 15:00 exponential distribution is a tricky beast. e.g., if corruptions happen on average every 3350 cycles, then i'd have a 5% probability of not seeing any in a test of 10000 cycles. but any user would also have a probability of 5% of seeing it within only 170 cycles. it may not take very long to reach this point. 2011-10-16 15:02 and there's a 1% chance of hitting it within only 35 cycles. and so on. 2011-10-16 16:34 DocScrutinizer: schematics page 8, left edge, J12 through J15 are the feet. how do you like that ? the connect to four corners of the main ground area 2011-10-16 16:41 wpwrak: URL of schematics please 2011-10-16 16:45 http://milkymist.org/mmone/rc3_schematics.pdf 2011-10-16 17:35 I edited the wiki on the "Format Data Partition" page.  The edit is at the end of the ubifs startup section.  I added the line linking /etc/init.d/start to /etc/rc.d/S99start. 2011-10-16 17:37 I am a newbie to linux and to openwrt.  Please feel free to edit my edit.  I made a best guess at what should take place but may be very wrong. 2011-10-16 17:39 "/etc/init.d/start enable" should create the symlink accordingly 2011-10-16 17:40 newTopic:  Could someone point me in the right direction regarding suspend on the ben?  I would like to get more time out of the nanonote so that I can use it at work all day without recharging. 2011-10-16 17:40 this is usually cleaner as it also treats the START= variable correctly 2011-10-16 17:41 jow_laptop:  Thanks.  I will change the wiki. 2011-10-16 18:27 are people responsible for ben liballegro port in here? 2011-10-16 19:28 wpwrak: hi 2011-10-16 19:29 I've tested the board--looks like the boost and logic parts of it work, but now there's another problem 2011-10-16 19:29 there is a backlight power converter in the LCD screen, it is powered by 12V 300mA 2011-10-16 19:30 we have a 12V converter module (sealed and so on) 2011-10-16 19:30 rated 2A 2011-10-16 19:31 on the power on, the power converter does "bzzzZzZzZ(khrzzkhrzzkhr){10}zz.", and, during that, the voltage at converter output is ~6.5V 2011-10-16 19:31 after it silences out (it turns off at overcurrent), the voltage is ~7V 2011-10-16 19:31 the lamp emits only a very dim light during the bzzzz'ing 2011-10-16 19:32 what can be wrong? 2011-10-16 19:32 maybe you have an idea or two :) 2011-10-16 19:36 oh, it's rated 500mA, and 2A is the maximal peak current 2011-10-16 20:40 should still be enough. during the test, is is loaded ? 2011-10-16 21:04 hm 2011-10-16 21:05 the lamp is connected, and the 12V converter is attached to HV converter before I turn everything on 2011-10-16 21:05 I guess it is, then 2011-10-16 21:12 odd then. well, check the current ... 2011-10-16 21:13 (input current first) 2011-10-16 21:34 hmmm 2011-10-16 21:34 it now "works" in a different pattern 2011-10-16 21:35 it emits a quiet buzz, which is sometimes interrupted by a "scratch" (sounds quite like a spark, but there are no visible sparks, no heat and no smell) 2011-10-16 21:35 the lamps glow very dim (but they definitely do) 2011-10-16 21:35 and the current is 170mA 2011-10-16 21:36 @5V 2011-10-16 21:40 the output voltage is 5.5V, and the input is 4.63 (down from 4.92 normally) V 2011-10-16 21:41 I guess it's because I am powering it from a different (USB) power source 2011-10-16 21:45 I've tried to attach a spare lamp I had lying somewhere 2011-10-16 21:45 it actually lights up for a second intermittenly (i.e. it is on 99% of the time, but it flickers), and it turns off soon 2011-10-16 21:49 hmm, odd. dunno. maybe a bad module ? 2011-10-16 21:50 it worked in the notebook 2011-10-16 21:50 or do you mean the 12V boost one? 2011-10-16 21:52 the noise is emitted by HV coil. neither it nor the controller build up any heat 2011-10-16 21:55 even if it is the inverter, they cost near to nothing 2011-10-16 21:55 http://www.pchub.com/uph/laptop/43-25222-2183/YEC-YNV-C02-LCD-Inverter.html 2011-10-16 22:03 "CAUTION  HIGH VOLTAGE" hmm :-) 2011-10-16 22:09 according to leaked FCC test results, it's 1.5mA@1.4kV 2011-10-16 22:09 and the input current is 33mA 2011-10-16 22:09 hm. 2011-10-16 22:09 wait, what? 2011-10-16 22:10 does it have some kind of perpetuum mobile inside? :D 2011-10-16 22:12 I've powered it off a SLA accumulator with the same result 2011-10-16 22:12 it's quite discharged, through 2011-10-16 22:13 so what does that have to do with your 12 V converter ? it this a third converter in your system ? 2011-10-16 22:21 fourth, actually 2011-10-16 22:22 i somehow wonder if it wouldn't have been easier to just get some cheap tablet and remove the case ;-) 2011-10-16 22:23 I have a board (yes, that's mine too) which charges Li-Poly accumulators and converts their whatever voltage to 5V 2011-10-16 22:25 then, there's a buck which converts that 5V to 3.3V (actually, 3.47V due to only E24 resistors available) to power the logic of LCD 2011-10-16 22:25 there is a boost 5V->12V which I've already described 2011-10-16 22:25 and 12V->HV which powers the backlight 2011-10-16 22:26 as the motherboard, a StarterKit board is used... remember I've told you about the board with an LDO which gets so hot that PCB turns black? 2011-10-16 22:26 that one. 2011-10-16 22:26 so, no switching converters there :D 2011-10-16 22:27 sounds massively complex :) 2011-10-16 22:27 not any more complex than a random netbook 2011-10-16 22:27 my one has IIRC five converters 2011-10-16 22:27 not counting the one in power supply 2011-10-16 22:28 yes. but a netbook can probably do a bit more, no ? :) 2011-10-16 22:28 yes, taking a cheap tablet and removing the case is MUCH easier 2011-10-16 22:28 but it is also much less fun 2011-10-16 22:28 heh :) 2011-10-16 22:28 the resulting "thing" will be rougly equivalent by functionality to any ARM netbook 2011-10-16 22:29 it will be five times heavier and less convenient, of course, but on the other hand you'll have all the schematics and datasheets and docs and whatever 2011-10-16 22:29 quite in the spirit of OSHW 2011-10-16 22:30 (ahem) 2011-10-16 22:30 I'll happily publish eveything under WTFPL, but I doubt that some brave one exists which will try to replicate this design 2011-10-16 22:31 I was thinking about building a portable (luggable) Milkymist One case :-) 2011-10-16 22:31 also, it is quite dependent on the scrap parts I (and my friend who wants that) had lying around 2011-10-16 22:31 we can make a competition whose portable computer is heavier and bulkier... 2011-10-16 22:31 lol 2011-10-16 22:32 do you know this? http://chrisfenton.com/diy-laptop-v1/ 2011-10-16 22:32 http://chrisfenton.com/diy-laptop-v2/ 2011-10-16 22:33 the 1st one is super simple 2011-10-16 22:34 duh, the second is too 2011-10-16 22:35 yes, sure 2011-10-16 22:36 current "motherboard" we use runs Linux on some (I don't quite recall which) high-end Cortex-A 2011-10-16 22:36 do you have some pictures? 2011-10-16 22:37 yeah, quite a lot of them. I'm planning to write a small article on making the board 2011-10-16 22:37 I don't currently have any for the whole device, sorry 2011-10-16 22:37 forgot to take them 2011-10-16 22:38 wait a sec, I'll upload them 2011-10-16 22:40 I think that the final device will use a SODIMM module with CPU and RAM, and every other thing will be placed on a "hostboard" I'll make: power converters, smart battery system with two Li-Poly cans, LVDS adapter, maybe some more circutry 2011-10-16 22:41 I'd post a link to the module, but the site of the shop is currently undergoing some maintenance (it's 2:40 here in Russia) and 503's 2011-10-16 22:42 anyway, here it is (in the case the site will be up timetimes): http://www.terraelectronica.ru/catalog_info.php?ID=1177&CODE=677003&Name=TAM-3517&Razdel=%CE%F2%EB%E0%E4%EE%F7%ED%FB%E5%20%E8%20%EE%F6%E5%ED%EE%F7%ED%FB%E5%20%EF%EB%E0%F2%FB%20%E8%20%ED%E0%E1%EE%F0%FB%20%E4%EB%FF%20%F1%E5%EC%E5%E9%F1%F2%E2%E0%20Sitara%20(Cortex-A8%20%E8%20%20ARM9)&TableName=class_19_2_41_5_6 2011-10-16 22:43 ahh, it is this one: http://www.technexion.com/index.php/arm/ti-sitara-am3517/tam-3517 2011-10-16 22:47 wolfspraul: http://imgur.com/a/2V0vl 2011-10-16 22:56 any comments? :) 2011-10-16 22:59 one sec 2011-10-16 23:00 ok nice! I need to learn more about your project for better overview... 2011-10-16 23:02 not sure if everyone on this channel wants to hear about it 2011-10-16 23:02 I'll PM you 2011-10-16 23:03 why not? 2011-10-16 23:04 ah okay 2011-10-16 23:04 please keep the channel posted :-) 2011-10-16 23:04 so, the ultimate goal of this project is a notebook made from as many perfectly known parts  as it is possible 2011-10-16 23:04 *not notebook, but a tablet 2011-10-16 23:04 the notebook was a year ago :) 2011-10-16 23:05 the core of it will be a high-end ARM like Cortex-A 2011-10-16 23:05 with a lot of memory and Linux on-board 2011-10-16 23:05 I will follow more closely 2011-10-16 23:05 gotta run now, bbiab 2011-10-16 23:06 hmm 2011-10-16 23:06 should I wait for him or just leave that in the logs?.. 2011-10-16 23:20 wpwrak: how would you design something netbook/tablet-like without a lot of switching power supplies? 2011-10-16 23:20 you have just Li-Poly voltage which varies between 2.8V and 4.2V per cell, and you need: Vdd=3.3V, Vbus=5V, Vcore=1.8V, Vbacklight=12V (or whatever), maybe more 2011-10-16 23:21 and a li-po charger is a step-down converter too 2011-10-16 23:22 so, five at least 2011-10-16 23:37 ha, after all i discover a mprintf implementation inside gnsssdr.ru osgpa port to solve the unsigned issue fot the 16bits data 2011-10-16 23:37 so it can print signed :) 2011-10-16 23:38 wpwrak: yes i do have friends with CNC and better prices than when M1 case 2011-10-16 23:39 still waiting invitation for altium live so can get the viewer 2011-10-16 23:41 oh,  OsmocomGMR annonuce :) 2011-10-16 23:43 wpwrak: is okay to ignore that is still having 0.38% of write fails to the namuru core i ported to M1? 2011-10-16 23:43 I'm about to implemnt a "ramdon" write test and see how it goes, but i'm little concern that i still no getting zero errors report. 2011-10-16 23:44 that's register writes ? failures sound like trouble ... 2011-10-16 23:45 control and status register.. i added some general porpuses there to run some basic test initially to measure troghput and later to verify writes 2011-10-16 23:46 and actually that may explain why some code dint worked in rtems but do i the m1 bios 2011-10-16 23:48 hmm. i think you want to debug your registers before relying on them. otherwise, you'll always suspect a register problem when something goes wrong. 2011-10-16 23:48 k 2011-10-16 23:52 i'll try this as the torture test http://www.codeproject.com/KB/recipes/SimpleRNG.aspx :) 2011-10-16 23:55 nice and simple :)