<azonenberg> kristianpaul: I set up the google code project "homecmos" and google group "homecmos"
<azonenberg> Lab blog is on the to-do list
<azonenberg> Right now i have just been posting status updates to my facebook :P
<azonenberg> But that needs to change
<azonenberg> probably gonna set up another blogspot for it
<azonenberg> I already have one, "siliconexposed"
<azonenberg> for my IC reversing work
<kristianpaul> Btw, what are considered material related to semicoductors
<azonenberg> You mean semiconducting materials? Or materials used in fab / research
<kristianpaul> last one
<azonenberg> Silicon is the main actual semiconductor used, germanium and gallium arsenide are used in microwave stuff and LEDs
<azonenberg> Phosphorus, boron, and arsenic are used for P and N type doping
<azonenberg> Aluminum for interconnect wiring, replaced by copper in newer high-speed chips
<azonenberg> Copper ions tend to diffuse and contaminate PN junctions so the copper is usually isolated by some kind of barrier material
<azonenberg> titanium nitride and ruthenium are two i recall specifically
<azonenberg> For dielectric normally you use SiO2
<azonenberg> newer processes use high-K dielectrics like tantalum pentoxide
<azonenberg> Which i was actually considering using in my process but for a totally different reason (hardmask for wet etching, the stuff is pretty impervious to KOH but is etched quickly in dilute HF)
<azonenberg> Low-K dielectric between wiring layers of newer chips, dont know of any specific materials though
<azonenberg> For processing, various photoresists and developers
<azonenberg> KOH, tetramethyl ammonium hydroxide (TMAH), EDP, and other water-amine complexes for anisotropic wet etching of silicon
<azonenberg> HF for wet etching of SiO2 and some metals, other acids for other metals
<azonenberg> Lots of fluorine based gases for RIE
<azonenberg> And chlorine, halogens in general
<azonenberg> SF6, CCl4, ClF3
<azonenberg> Argon, as an inert gas for sputtering and purging of stuff
<azonenberg> Nitrogen, for forced-air drying of wafers, purging, and in some cases reactive sputtering to form nitrides and oxynitrides
<azonenberg> there are more but those are the ones that come to mind in particular
<kristianpaul> Sourcing those should no be hard i guess :-)
<azonenberg> Lol, many of them are hard
<azonenberg> But my processes will be using a much smaller subset of those materials
<azonenberg> I'm actually going to start documenting a lot more stuff in the near future, probably going to start the blog tonight
<kristianpaul> wpwrak: (386dx) wow now i realize the µm times :-)
<azonenberg> 4004 was on a 10um PMOS process iirc
<azonenberg> Can you imagine making a 1:1 scale working replica? :D
<kristianpaul> :D
<azonenberg> There will def be some process changes though, 4004 was not made to use high-K dielectric
<azonenberg> It probably used polysilicon gates, my process will be using metal
<kristianpaul> lets change that to a navre core IC ;)
<kristianpaul> at least you mips core was tought to fit in your photolithography research :o
<azonenberg> Well, the first step is MEMS as i can get away with much looser tolerances etc there
<azonenberg> Then, single transistors
<azonenberg> simple CMOS logic cells
<azonenberg> And if i can pull that off - a couple of standard cells plus interconnect wiring
<azonenberg> Then its time to start thinking bigger
<kristianpaul> :-)
<azonenberg> And smaller, as well
<kristianpaul> and smarter than intel ;-)
<azonenberg> Lol not just yet, i have a ways to go still
<kristianpaul> "Why not change the world?" nice slogan, you catch it very well :-)
<azonenberg> lol
<wpwrak> in what other industrial process but semiconductors is the substrate used ? i.e., what are the chances of sourcing it internationally
<wpwrak> s/process/processes/
<azonenberg> I'm only concerned about US vendors right now as thats where i'm located
<azonenberg> but there are a lot of international fabs
<azonenberg> in fact, *most* fab is done in the far East - china, taiwan, etc
<azonenberg> japan
<wpwrak> i'm thinking of poor agrarian countries, like argentina :)
<azonenberg> Oh... you are not likely to find semiconductor grade silicon there very easily lol
<wpwrak> sigh
<azonenberg> your best bet will be ebaying etc probably
<kristianpaul> azonenberg: Is it only you, or it will be an interdiciplinary research?
<azonenberg> You mean, am i the only person on the project?
<kristianpaul> yes
<azonenberg> As of now i'm the only really active person but i'm bouncing ideas off of a bunch of friends and colleagues
<wpwrak> maybe go to the beach, get a few bags of sand. then make some kitchen experiments. after all, the secret is in the impurities, right ? :-)
<azonenberg> Lol
<azonenberg> Good luck getting five nines (or probably six or eight, actually) purity silicon out of sand at home
<azonenberg> I'm doing the fab, not the materials production
<kristianpaul> hum
<kristianpaul> wpwrak: are you swiching from ceramics to sand now? :-)
<wpwrak> kristianpaul: what did i do with ceramics ?
<wpwrak> i kinda like the picture of a little x/y blue ray laser "printing" me some chips :) you know, kinda "make cpu". first runs llhdl, then prints the chip. voila. nicely integrated process.
<azonenberg> Well, its a little more complex than that
<azonenberg> The bluray module won't have alignment capability
<azonenberg> You'll use it to make the masks
<kristianpaul> wpwrak: dunno, i just tought had something in mind.. thats all :)
<azonenberg> But then a contact aligner will be necessary to actually fab the chip layer by layer
<wpwrak> azonenberg: for alignment, if you can get a substrate that's smaller than the movement range of the x/y laser, you could just align with chip edges (photo sensor on the other side, chip blocks laser light or not)
<azonenberg> Too imprecise
<azonenberg> i'd need theta, magnfiication, etc
<azonenberg> Substrate dimensions will not be precisely controlled
<azonenberg> I'll be fracturing along cleavage planes
<wpwrak> maybe you could scan the outline ?
<azonenberg> I'll need optical alignment using purpose-built alignment markers on the chip surface
<azonenberg> The thing is, doing that with laser direct write will be tricky
<azonenberg> Doing it by hand under a microscope is a lot easier
<azonenberg> The standard alignment mark is a cross on the bottom layer
<azonenberg> then a hollow cross on the next one
<azonenberg> that you fit over it
<azonenberg> You have one at each side of the die to detect slight theta shifts
<wpwrak> but they're mainly used for the same laser, right ?
<azonenberg> Most production systems don't use lasers
<wpwrak> if we assume direct exposure
<azonenberg> They use electron beam direct-write (similar to the laser process i'll be using) to create a photomask in chrome on copper
<azonenberg> And then you run that through a contact or projection exposure system
<azonenberg> the key is that the mask-fab process is distinctly separate from the alignment and exposure process
<wpwrak> i'm thinking of the x/y BR laser. if you can scan the chip's outline, you could probably reproduce its orientation and position quite accurately
<azonenberg> outline of the die?
<wpwrak> yes
<azonenberg> bear in mind that i'll be taking little fractured pieces of silicon and then patterning a square in the middle of them
<azonenberg> Also, scanning will require optical pickups, a camera, vision software
<wpwrak> perfect. the more fractured, the more information :)
<azonenberg> I'm not saying it's impossible
<azonenberg> But it will definitely not be easy and is certainly not a rev1 or even rev2 capability
<azonenberg> Real production steppers do something similar
<azonenberg> They scan the alignment markings on the first mask level and line the new mask up to that
<azonenberg> all done automatically with no human intervention
<wpwrak> naw. you already have the BR laser. put a photo diode on the back. check if you have a beam or not. take lots of data points. filter/average/etc.
<azonenberg> The key is getting good resolution
<azonenberg> we're talking submicron here, potentially
<azonenberg> you cant just use a photodiode, you'd need a full camera
<wpwrak> i would expect that you can get good resolution statistically
<azonenberg> You could, but that means much more intensive DSP capabilities
<wpwrak> pc time is cheap ;)
<azonenberg> Not for a realtime process
<azonenberg> If you can't automate it faster than a human can align it?
<azonenberg> Not worth the trouble
<wpwrak> do you care so much about time ? for a DIY ultra low-volume process, you can omit a lot of things the industry does
<azonenberg> Exactly, such as automated alignment
<azonenberg> Which is why i am using a manual alignment process instead
<wpwrak> industry is all about throughput and yield. none of this matter much to you. for you, everything is in the setup cost.
<azonenberg> Which is cheap to set up and requires minimal hardware
<wpwrak> doesn't the manual process need fancy extra equipment ?
<azonenberg> Did you read my paper?
<azonenberg> It was pasted to the channel a few times
<azonenberg> It's just a converted microscope (that still functions as a regular microscope, in fact)
<wpwrak> heh, i guess i should :)
<azonenberg> print the mask pattern on a laser printer at 200 microns per pixel (the limit of my cheap printer, 150 is doable sometimes but closely spaced lines will blur together)
<azonenberg> And use the microscope optics run backwards to project the pattern onto the die
<kristianpaul> just in case ;)
<wpwrak> kristianpaul: thanks !
<azonenberg> The first process i described there got me to 15um per pixel on the actual die
<azonenberg> The second one is still being refined, i've hit 5um per pixel but it didnt expose evenly across the field
<azonenberg> i need a more intense UV source and a diffuser
<azonenberg> which is going to be ordered next payday :P
<wpwrak> azonenberg: okay. but that's the process that gives you a very limited field. i'm talking about the x/y BR laser. that shouldn't need a microscope, right ?
<azonenberg> My plan, actually, is to combine the two
<azonenberg> Use the laser direct write process instead of the printer to make masks
<wpwrak> laser through the microscope ?
<azonenberg> use a low-power objective (say 4x) to project this mask slightly reduced onto the die
<azonenberg> and align through the microscope
<wpwrak> ah, okay. i thought you'd go 1:1 with the laser
<azonenberg> I considered it
<azonenberg> But this lets me get away with lesser tolerances on the laser
<azonenberg> also, direct write is slow
<azonenberg> This way, if i fix a bug on metal 3
<azonenberg> i can reuse the M1/M2 etc masks
<azonenberg> and only redo the M3 mask
<roh> making navre on silicon would be so cool
<azonenberg> navre is what? softcore CPU?
<roh> could enable a fully idea->hw toolchain for avr stuff
<roh> navre is a avr core in verilog.
<wpwrak> hmm. i still kinda like the idea of a maskless process. fewer moving parts :)
<azonenberg> Ah
<azonenberg> wpwrak: Maskless is nice in theory but is awkward
<azonenberg> My thinking is, sputter a microscope slide in metal and direct write on that
<roh> so one could do a 'no non-free parts' adruino ;)
<azonenberg> then use the mask in my current process
<azonenberg> Also, has anybody tried synthesizing navre in an ASIC tool?
<azonenberg> rather than fpga
<azonenberg> as in, getting actual gate counts etc
<wpwrak> (asic tool) probably not. at least i didn't see lekernel mention anything like this
<roh> i think one also needs some io units
<wpwrak> azonenberg: hmm, seems that a BR reader would already have a strong enough diode. makes things nicely inexpensive :)
<roh> now its only a core with some sie for usb
<wpwrak> roh: some gpios probably wouldn't be too hard to implement. even output-only would be sufficient for showing off ;-)
<wpwrak> well, you need some input mechanism for loading the code. spi perhaps.
<roh> wpwrak: true. but then i think it would make more sense adding some units like serial etc.
<roh> doesnt even need to be a atmel style copy, could be different. do changes in avr-libc
<wpwrak> roh: i'd just focus on plain brag value, i.e., core and whatever else is easiest to do :)
<kristianpaul> argg, 0000
<kristianpaul> what i missed..
<kristianpaul> WB Write: 00001000=12345678 acked in           1 clocks
<kristianpaul> WB Read : 00001000=00000000 acked in           1 clocks
<kristianpaul> :/
<CIA-48> flickernoise: Xiangfu Liu master * r2b78537 / src/performance.c :
<CIA-48> flickernoise:  add missing head file <osd.h>
<CIA-48> flickernoise:  merge 'firstpatch' and 'simple_current' to 'current_patch'
<CIA-48> flickernoise:  press 'F1' when rendering will display the patch name
<CIA-48> flickernoise: Signed-off-by: Xiangfu Liu <xiangfu@sharism.cc> - http://bit.ly/iDLjQ8
<azonenberg> wpwrak: Agreed
<azonenberg> My first project will be a simple MEMS comb drive, once i get that working i'll make a transistor
<azonenberg> then gates
<azonenberg> First actual CMOS project will be a ring oscillator
<azonenberg> That alone, in a 5um homebrew process, will be worth quite a bit for bragging rights lol
<wpwrak> oh yes ;-)
<azonenberg> Even if it is just a "hello world" circuit lol
<azonenberg> But there will be a lot of work needed before i'm even close to there...
<wpwrak> you can always do that 4 GHz hexacore another evening ;-)
<azonenberg> Lol, i dont plan on doing that any time soon :p
<wpwrak> yeah, you'll want that 8 nm process for it. so that's a couple more years.
<azonenberg> lol
<wpwrak> i still find the idea of converting two BR drives into an xy plotter intriguing. maybe even some of the drive electronic could be reused.
<azonenberg> only one drive
<azonenberg> just get a precision linear stage
<azonenberg> put the single axis perpendicular
<wpwrak> mmh. one axis would be the sled. what drives the other axis ?
<wpwrak> or would you spin the die, like a disc ?
<azonenberg> The sled would be sitting on top of a linear actuator of some sort
<azonenberg> like used for an automated microscope focuser or similar
<wpwrak> i don't know these. but another BR or DVD sled ought to be a cheap linear actuator, no ?
<wpwrak> preferably the same BR, to keep the drive circuit simple
<wpwrak> just pull the laser. use it to scare pigeons or such
<azonenberg> Perhaps
<roh> hm. how much H and V move do you need on the laser?
<roh> the 'sled' isnt the only thing moving there. usually one moves the laser on a cheap and imprecise sled and has a magnetic lens holder
<azonenberg> Correct
<roh> means 2 moving coils around the lens. one for focus, one for fine-alignment
<azonenberg> I was planning on having a relatively loose tolerance on the direct-write system
<azonenberg> getting maybe 50 microns per pixel or so
<azonenberg> and then further reducing in the projection system
<azonenberg> I just want something that can go better than the 200um/pix of my cheap laser printer
<azonenberg> and will make darker masks (chrome on glass)
<roh> so if you need only small movements... use the H coil only... not the dc servo
<azonenberg> and the masks will be up to maybe 1cm^2
<azonenberg> which is, in fact, about the travel range of the servo end to end
<roh> hm. how about using commercial services for stuff like that? friends of mine give away digital images and get film back for projections on whole walls
<azonenberg> Sure, that's an option
<roh> its really tiny and sharp.. and not that expensive
<azonenberg> And thats definitely at least 50um resolution
<azonenberg> But is it chrome on glass, or on plastic?
<azonenberg> If plastic it's less stiff and flat
<azonenberg> and you can get focusing etc issues
<azonenberg> Which is a problem with my current system, actually
<roh> i think its plastic. but there should be options for glass since that stuff gets quite hot in the projectors
<azonenberg> But is it ink on glass?
<azonenberg> Or metal
<azonenberg> I dont think its metal
<roh> dunno. will ask
<azonenberg> The whole idea of the direct write system was to get metal-on-glass masks
<azonenberg> Laser printer or commercial print shop, same deal
<azonenberg> it's still think plastic
<roh> maybe the machines used to copy to microfiche would be of some help
<wpwrak> azonenberg: the sled should be able to travel a bit more than 3 cm (for a 12 cm disc). so you'd get at least 9 cm2. plenty of room for that hexacore ;-)
<azonenberg> Lol, no way am i making 3cm^2 dies
<azonenberg> 3cm x 3cm*
<azonenberg> Trying to keep something that big planar and in focus? Not happening any time soon
<wpwrak> a bit of extra range could be useful for loading/unloading, calibration, etc.
<azonenberg> i'm shooting for 1cm x 1cm as a more realistic size
<azonenberg> However, that's per die
<azonenberg> Being able to make a stepper, and put multiple dies on a wafer in one session
<azonenberg> Would be very cool for the long run
<wpwrak> yeah, you probably want some optical feedback for beam size at some point in time. i wonder how the writers do it. when writing, what sort of feedback do they get ?
<wpwrak> aye. DIY mass production :)
<wpwrak> TSMC@Home
<azonenberg> lol
<wpwrak> for planarity, if you have a feedback system, you could just have focusing area between the dies, where you expose until the beam is right. then interpolate.
<azonenberg> I'm going to need a street between dies anyway for dicing
<azonenberg> What about direct write through the microscope
<wpwrak> i still wonder how the focus feedback works in BR drives, though. must be something simple.
<azonenberg> Microscope camera
<azonenberg> Realtime feedback of spot size etc
<azonenberg> And would permit alignment as well
<wpwrak> (street) good point. may as well "pave" it :)
<azonenberg> then just get a motorized stage
<wpwrak> microscopes tend to be expensive equipment
<azonenberg> I have one already is the point
<wpwrak> ;-)
<azonenberg> and its a $800 model
<azonenberg> not a $10K mitutoyo or zeiss
<wpwrak> see. a BR drive is something like USD 100 :)
<azonenberg> But then you need all of the control electronics, optics, assemblies to hold it all together
<azonenberg> And you'd need a scope for inspection anyway
<azonenberg> and failure analysis
<wpwrak> the optics ought to be in it already
<azonenberg> Nobody is going to be doing 5um fab if they can't even see 5um features
<azonenberg> A microscope is implied
<wpwrak> assemblies: a base plate and a few spacers, i guess
<wpwrak> (inspection) yes, that's true. still, it could be a lot simpler than one that you could use for exposure
<azonenberg> Not really, this scope is about the bare minimum you'd want for work like this
<azonenberg> you cant use a biological scope for opaque samples easily
<azonenberg> you need through-lens illumination
<azonenberg> and low-power 30-50x stereo ones arent enough power to see 5um features clearly
<azonenberg> trust me, i've tried :P
<wpwrak> i actually wonder how small you can get with a digital camera. not 5 um, that's for sure, but they should also have a pretty good resolution if you get close enough and manage to get some light source
<azonenberg> camera?
<wpwrak> as a poor man's microscope
<azonenberg> Pixel size is normally a few microns but you can't actually resolve that clearly
<azonenberg> they have bayer filters
<azonenberg> so 10+um is your actual resolution
<azonenberg> thats assuming you have a condensing lens to properly focus everything, ideal best case
<wpwrak> something 10-ish wouldn't be too bad
<azonenberg> realistically i think 50 is more reasonable
<wpwrak> probably something like 15-30 um. this image http://downloads.qi-hardware.com/people/werner/tmp/zoom-13_6mm.jpg
<wpwrak> is about 13.6 mm wide
<azonenberg> Yes, its 13.6mm wide
<azonenberg> so you say that's 15-30um per pixel
<azonenberg> But can you actually resolve two lins at that spacing?
<wpwrak> 1848 pixels
<azonenberg> s/lins/lines
<azonenberg> Or is it just empty resolution
<azonenberg> pixels with no meaningful data
<wpwrak> it's the nominal pixel width
<azonenberg> Correct
<azonenberg> I'm willing to be 3-5 pixels is your minimum actual resolution
<wpwrak> so that's about 7.4 um per pixel. now, how many pixels do we need for a real-life edge ...
<wpwrak> that would be 20-40 um
<azonenberg> Realistically, 10pix is what i see in most cheaper sensors
<azonenberg> So 20-80
<azonenberg> About what i expected
<wpwrak> dunno how much of the blur i have is sensor, focus, or motion. but yes, it's not quite good enough for your 5 um structures, let alone the 1-1.5 um of a 386dx
<azonenberg> Correct
<azonenberg> On the other hand, my nice scope...
<wpwrak> (focus) the camera doesn't autofocus properly at this short range, so i moved it until the image looked sharp in the LCD viewfinder. so i can probably squeeze out a few more um ;-)
<azonenberg> those lins are pretty small lol
<azonenberg> lines*
<azonenberg> iirc around 400nm pitch
<azonenberg> this is with contrast turned all the way up using oil immersion
<azonenberg> those marks are scratches on the sample
<azonenberg> thin plastic diffraction grating
<wpwrak> is the url correct ? the host doesn't resolve
<wpwrak> hmm. whois has it.
<azonenberg> Having some DNS issues
<azonenberg> 128.213.48.35
<azonenberg> is the correct IP
<wpwrak> hmm yes, nice resolution :)
<azonenberg> That's on the zeiss supra 55 SEM at my school's cleanroom lol
<azonenberg> metal 3 of a 350nm 3-metal chip at 50,000x
<wpwrak> and full of life ;-)
<azonenberg> i was doing a failure analysis job for a consulting customer and decided to play for a few minuts afterwards on some samples i had lying around
<azonenberg> No, actually
<azonenberg> those arent bacteria
<azonenberg> Look at the one at top left
<azonenberg> it's cracked open
<wpwrak> oh
<azonenberg> Those are glass beads from the packaging material
<wpwrak> dunno what cracked bacteria look like :)
<wpwrak> heh ;-)
<azonenberg> Lol, they dont show brittle fracture
<azonenberg> (bacteria)
<azonenberg> After the 150C boiling nitric acid to decap
<azonenberg> followed by rinses in acetone and isopropanol
<azonenberg> It's about as sterile as you can get lol
<azonenberg> Stored inside a closed container before being brought into the cleanroom
<wpwrak> well, it could still be dead bacteria :)
<azonenberg> I'd expect them to be completely lysed by the HNO3
<azonenberg> the other giveaway is the perfect spheres and large size range
<azonenberg> I mean, you could be right
<azonenberg> I didn't actually try IDing them
<azonenberg> i was just trying to get practice in focusing the thing just right
<azonenberg> idk if you've ever used an electron microscope but they're a little tricky to get good images out of
<wpwrak> the picture is pretty spectacular
<azonenberg> getting the last little bit of focus is hard
<azonenberg> you have two axes of astigmatism, two of aperture alignment, and focus to adjust
<wpwrak> so you'll have all you need to debug that 8 nm process for the hexacore ;-)
<azonenberg> Lol
<azonenberg> Cleanroom time is not cheap
<azonenberg> i cant afford to use it a lot
<azonenberg> $188.50 an hour
<azonenberg> What i do instead is, when i have to use it for work
<azonenberg> Sneak in at the end and shave 15 minutes off the bill when i send it to the customer
<wpwrak> hehe :)
<azonenberg> That way i don't have to pay for gowning, pumping down vacuum, etc
<azonenberg> Only for the time i actually used on my own stuff
<azonenberg> combined shipping, you could say ;)
<wpwrak> it's all about efficiency :)
<azonenberg> Yep
<CIA-48> mtk: Xiangfu Liu master * rd00cd70 / lib/keymap.c :
<CIA-48> mtk: keymaps: add French_layout_058
<CIA-48> mtk: Signed-off-by: Xiangfu Liu <xiangfu@sharism.cc> - http://bit.ly/lFAvOq
<lekernel> xiangfu: why do you persist adding new features to this code you will remove?
<xiangfu> lekernel: first make it work then make it better :)
<lekernel> only a short press is needed to boot
<lekernel> xiangfu: your other patch is ok
<xiangfu> (short press) thanks, I always hold it until screen show up :(
<xiangfu> forget to take a look serial output.
<lekernel> long press makes the splash screen appear
<lekernel> short press doesn't
<aw> lekernel, you are right on that we've used faulty 1206 beads in rc2.
<aw> which came from the same vendor but two shipments for rc1 and rc2.
<aw> meanwhile I fully made wrong measurements by ignored resistance from my extended dc jack cable.
<aw> after replaced right beads for L10/L11, the drop is 3.3mV ~ 3.5mV.
<aw> with calibrating my cable loss, the correct measured "5V" net voltage is 5.199V @ 5.25V input, 4.951V @ 5.0V input, 4.699V @4.75V input.
<aw> e.g. : when 4.75V in, the total divided dropped voltage = 0.0033 (VL11)+ 0.0035(VL10) + 4.699(V5v net) = 4.7436V, which is exact closely to 4.75V input.
<aw> corrected formula = 0.0033 + 0.0035 + 0.0378 + 4.699 = 4.7436
<aw> be noted that Vfuse = 37.8mV @ 44.7°C
<aw_> lekernel, hi i just wrote some msg log, you may read a bit while you were not here.
<aw_> lekernel, just see the bottom table, forget all others.
<lekernel> what is 'gnd loop cable loss' ?
<aw_> also be noted that my room temperature here is 33.3°C
<lekernel> I don't care about the room temperature
<lekernel> your numbers don't add up
<wolfspraul> wow, Taipei already that warm?
<lekernel> 4.75-4.55 = 0.20
<lekernel> 3.5+3.6+38+37+14 = 96.1 (instead of 200)
<wolfspraul> no I think you need to look at the next table
<lekernel> but this time the fuse drop voltage makes sense
<wolfspraul> aw_: we really have to cleanup that page and delete all data that is not really accurate. if we think that means we have to delete most data, then we should do that.
<lekernel> ah, the very last table
<wolfspraul> confusing data is worse than no data, and now we know that we overlooked the faulty l10/l11 for a while...
<wolfspraul> lekernel: yes :-)
<aw_> wolfspraul, surely deleted them after this discussions.
<wolfspraul> only leave accurate data
<lekernel> ok, better
<wolfspraul> I think the 4.699 at usb are acceptable (for a 4.75v input)
<lekernel> so we get 4.70V on USB in the (improbable) worst case... I think that's acceptable
<aw_> just see the bottom table.
<wolfspraul> so with my limited knowledge of electrical things, I'd say that looks good
<lekernel> ok
<lekernel> well the probability of failure is (probability of having the M1 power supply provide 4.75V)*(probability that the USB device fails for missing 50mV)
<lekernel> that's fairly low imo
<lekernel> btw, maybe we can leave only one of the beads in place?
<lekernel> and directly connect GND
<aw_> lekernel, thinking...
<wolfspraul> bbiab
<aw_> wolfspraul, what's 'bbiab'?
<lekernel> so what i'd recommend is 1) remove the bead on GND 2) implement the latest protection circuit
<lekernel> given that it doesn't end up in a layout nightmare
<aw_> here's data that i recorded real DC adapter's 'no load' voltage: http://downloads.qi-hardware.com/hardware/milkymist_one/doc/production/AC_to_DC_adapter.ods
<aw_> lekernel, the output with 'NO LOAD' at least 4.9V above, so the probability is very low.
<lekernel> ok, ok, don't do too much
<lekernel> how do you feel about adding the protection circuit to the PCB layout?
<aw_> the two Zeners needs placed in 90 degree not lie down to touch pcb surface.
<aw_> from the *.ods file, seems that we need to take risk on adding protection circuit.
<lekernel> btw, maybe we can remove the PTC on USB as well
<lekernel> since we already have a 'general' one
<aw_> placed in 90 degree, one pin needs to add insulation tube.
<lekernel> (F1)
<aw_> lekernel, can't understand your on USB.
<aw_> remove?
<lekernel> remove F1
<lekernel> yes
<lekernel> there was a PTC specially for the USB ports
<lekernel> we don't really need it if there is a PTC at the input now
<aw_> yes,
<aw_> well...probably not good idea...the hold current F2 is 2A , trip on 4A,
<lekernel> 4A won't damage the USB connector
<aw_> i doubt that user may produce more than 1A thus 1.76A there said even 2.76A, the F2 still haven't tripped though.
<lekernel> and that second PTC drops voltage too
<aw_> yes, i know F1's drop.., well...thinking..
<wolfspraul> aw_: bbiab = be back in a bit
<lekernel> you think too much
<lekernel> :p
<aw_> lekernel, you really want directly remove F1?
<lekernel> yes
<lekernel> and remove one of the beads, too
<lekernel> L11
<aw_> hm...welll...we can always take this risk, so can do DNP F1, but instead mounts a 0 ohm for F1, how do you think?
<lekernel> don't mount 0 ohm. just short the tracks in the layout
<lekernel> for L11 use 0 ohm unless you need PCB layout space to implement the protection. in that case, short the tracks as well.
<aw_> you are think the 0 ohm +/- 5%, right?
<lekernel> no I want to keep that thing simple because everything we add is a source of problems
<aw_> but if later someone do a horrible USB hub extended experiments, how he can add fuse by himself?
<wolfspraul> nobody will add a fuse by themselves!
<aw_> well...taking risk is take risk though.
<aw_> hmmm:-)
<wolfspraul> no let's just design a regular consumer product here.
<lekernel> it NOT a risk. the product will still work without F1 unless someone makes a very big mistake with the PCB design
<wolfspraul> aw_: you don't need to think about all sorts of hardware hacks. those people need to know what they are doing.
<lekernel> and, as a matter of fact, many consumer products allow you to overload the USB ports
<wolfspraul> aw_: remove parts is good. if lekernel thinks they can be removed, let's remove them unless you have a very good reason not to, which I cannot see right now.
<aw_> well...i have no further comments on this. so conclusions are:
<lekernel> 4A transient (actually limited to 2A by the power supply) isn't a major danger for the USB ports
<aw_> 1) remove F1, and short by layout.
<aw_> 2) remove L11, ans also by short layout change.
<aw_> 3) place Zener in 90 degree for better heat dissiplation.
<aw_> is it all?
<lekernel> aw_: the zener does NOT dissipate ANYTHING unless the user does a mistake. there is no need to optimize dissipation
<lekernel> so optimize cost and manufacturing time, instead
<aw_> there's still have space between U13 and DC jack.
<aw_> i think I will put fuse from away those two Zeners a little.
<lekernel> put the fuse anywhere it fits without making the layout a mess
<aw_> so you mean 3) just lie down two Zeners. :-)
<lekernel> if that's easier for layout/manufacturing, yes, definitely
<wolfspraul> 4) cleanup the long wiki page and delete all data that we now believe is not accurate. do not measure more data, just delete the bad data.
<aw_> actually here those two are lie down. :-)
<lekernel> damn I can't believe we managed to solder 485 components per board so far :P
<aw_> 4) surely, they came from messy ignorance on cable loss, stupid.
<wolfspraul> 5) find the root cause for the 1206 bead (wl262) sourcing problem and make sure the lot for rc3 is good
<wolfspraul> 4) and also from not seeing the l10/l11 problem earlier
<lekernel> aw_: do you confirm the L10/L11 problem on some of your boards?
<wolfspraul> yes
<wolfspraul> :-)
<wolfspraul> and we paid 1.46 USD per bead!
<wolfspraul> something went wrong there
<wolfspraul> at digikey they are more like 20 cents...
<aw_> 5) the root cause I may hard to catch out, if vendor don't tell me the truth.
<wolfspraul> even for that it's a great catch
<lekernel> 1.46USD/bead? wtf?
<aw_> so 5) I'll only source that 1206 bead myself though.
<wolfspraul> 5) what I mean is that we make sure this is good for rc3
<lekernel> those should only be a few cents
<wolfspraul> lekernel: yeah. 12 USD for all 8 of them :-)
<lekernel> urgh
<wolfspraul> like I said, I suspect human error somewhere.
<wolfspraul> that can happen, it's a manufacturing mistake on our side
<wolfspraul> very good catch
<wolfspraul> I don't think this was intentional fraud/rip-off anywhere, just some mismatch/whatever error.
<aw_> lekernel, I'll modify pre-rc3 sch again...then reply.
<wolfspraul> aw_: everything settled now?
<aw_> wolfspraul, what's your meaning?
<wolfspraul> whether you have any more open issues on these matters that block rc3
<aw_> 1) to 5) , will done.
<aw_> hm...
<wolfspraul> is there anything connected to 1-5 that worries/bugs you?
<wolfspraul> or that is it now?
<aw_> lekernel, have you added that diode on your board for reset flash chip?
<lekernel> no
<aw_> wolfspraul, no , done.
<wolfspraul> aw_: remember to rework the remaining for-sale rc2 with good beads on l10/l11
<aw_> can you add to confirm?
<aw_> wolfspraul, yes,
<lekernel> I don't have the reset IC, so it'd be of limited use
<lekernel> but I trust you on that one
<lekernel> anyway your schematics is correct
<aw_> lekernel, i remembered that i tried 1000 attempts for testing 're-configuration'
<lekernel> yes
<lekernel> so it should be good
<aw_> but today I tried to use my another board, it seems not work every time on 'booted' ....but all 're-configuration' is all good.
<lekernel> wolfspraul: there should be the 'bead dropout' problem at the output of the regulators too
<lekernel> actually, probably those beads can be replaced by 0 ohm, as Joerg said
<aw_> so can you add one low forwarding voltage diode to confirm ?
<lekernel> I didn't want to spend time investigating this, but now that we get bead issues ....
<wolfspraul> which ones?
<lekernel> all the other 6
<aw_> lekernel,  i don;t think so
<aw_> 0 ohm +/- 5%  has tolerance which may acts the small resistance like bead 0.01 ohm for the best though
<lekernel> I was talking about Joerg's argument that those beads are useless at best
<aw_> also if we replace other bead with 0 ohms, means we 1) tried to cost down  2) without considering emi
<lekernel> yeah sure
<lekernel> aw_: no, I won't try the diode. I don't have the parts for that, nor the time to try it.
<lekernel> plus you did testing that was extensive enough
<lekernel> plus there is a very low risk of major regression
<wolfspraul> lekernel: you want to replace all other 6 1206 beads with 0 ohm?
<wolfspraul> or which ones
<aw_> hm...okay...if rc3, i got failure on that diode, we can just DNP it.
<wolfspraul> you need to tell Adam, and either he adds it to his list or not...
<lekernel> wolfspraul: all the beads in series with the outputs of the regulators, as Joerg said
<lekernel> but no, don't try it if it's another source of delays
<wolfspraul> no delay
<wolfspraul> aw_: what do you think?
<lekernel> which is what I feared initially
<aw_> wolfspraul, well...i just test my old board which not every time 'booted' successfully...but I do real sure that reset ic is good though, my new rc2 board I'll add diode again to see if 'booted' every time
<wolfspraul> we didn't talk about the diode
<wolfspraul> that one is settled
<wolfspraul> let's not go back again and again to the same old issues
<aw_> wolfspraul, hmm? so which one?
<wolfspraul> "replace all beads in series with the outputs of regulators with 0ohm"
<wolfspraul> aw_: do you want to do this?
<aw_> i can try it or not try it because we passed FCC & CE in German, didn't we? so if we replace with 0 ohms, should we do certification again? if the answer is NO, we leave those beads, or we mount 0 ohm.
<wolfspraul> what?
<wolfspraul> don't understand
<wolfspraul> I cannot assess the risk of removing the beads _worsening_ the EMI.
<wolfspraul> but I also cannot always let fears guide my decision making
<aw_> we've got report from german, right?
<wolfspraul> if those beads are stupid and nobody knows why they might worsen EMI, then I would still remove them
<wolfspraul> if there is someone with experience who says that removing them may very well _worsen_ the emi, then I would be cautious
<wolfspraul> so do we have someone with that kind of experience?
<wolfspraul> I can totally remove them and _assume_ that emi is the same or better as before.
<wolfspraul> I'll just say it until someone proves me wrong :-)
<aw_> so i said that if we mount them with 0 ohms, I don't know if influence emi result even now I've not viewed all regulator's output beads spec.
<wolfspraul> sounds like we leave everything as-is
<wolfspraul> I don't want another drama on measurements etc.
<wolfspraul> lekernel - what do you think?
<wolfspraul> aw_: unless we hear from lekernel, let's leave them as they are
<wolfspraul> focus on the other stuff, L10/11, fuse/zener etc.
<aw_> wolfspraul, they are couple cents though, yeah..
<wolfspraul> aw_: when do you start working with the layout people?
<aw_> already started...tomorrow I'll send it as a pre-layout file after modifying todo about pre-rc3 sch.
<wolfspraul> aw_: ok, make sure to send me the png silkscreen for review about the logos and text position/size etc.
<wolfspraul> send to the list, then everybody can see it if they like to :-)
<aw_> yeah...i'll capture it
<aw_> dinner...k
<lekernel> yeah let's leave them... don't want to go through another round of measurements
<wolfspraul> for sure not
<wolfspraul> lekernel: do you think removing them may worsen emi?
<wolfspraul> I thought joerg was pretty sure they could not possibly do any good.
<lekernel> I don't know, maybe
<wolfspraul> ok
<wolfspraul> we leave them
<lekernel> yes, I can follow Joerg's reasoning, but on the other hand a lot of designs have them. maybe everyone is wrong and Joerg is right though :)
<lekernel> anyway - small detail
<wpwrak> wolfspraul: do you plan to re-check EMI/CE/FCC after all the rc3 changes are done ?
<wolfspraul> wpwrak: no
<wolfspraul> CE is a self-certification, and for FCC it's similar because m1 is a 'non-intentional radiator' and for those it's enough if the manufacturer says that the device meets requirements
<wolfspraul> no FCC ID is issued, so the question of whether a new FCC ID needs to be issued after making production changes (which happen all the time in reality) doesn't even come up
<wolfspraul> now, if I would be worried that after our rc3 changes the actual tests would show a problem, then I would want to know that, and I would look into the problem
<wolfspraul> but I cannot just test over and over again for every little change we make, for what reason?
<wolfspraul> the next time I go back to that lab, I would try to look into the ESD issue that forces us to put a metal sheet under the PCB
<wolfspraul> and as a side-effect we could also re-test the whole system including all changes made by then
<wolfspraul> but I see no urgency for this, at all
<wpwrak> wolfspraul: alright. wasn't the metal sheet for EMI ?
<lekernel> wpwrak: it was to protect from malfunction due to perturbations caused by nearby external ESD discharges, which is indeed a form of EMI
<wpwrak> oh, that's a subtle one
<lekernel> azonenberg: http://warrantyvoidifremoved.com/ is coming instead of you, presenting DIY metalwork and jewelry :-)
<lekernel> hopefully there will even be a workshop as well
<kristianpaul> ha, now i realize how usefulls verilog tasks are :)
<kristianpaul> :o
<kristianpaul> you made it !!
<lekernel> nah, I just submitted it
<kristianpaul> ah..
<kristianpaul> ah yah..
<lekernel> now there's still a risk it gets voted down (in fact it happened to many of my slashdot submissions already)
<kristianpaul> i put in doubt the Consumer device part.. but let see
<kristianpaul> haha
<lekernel> nah. we'll get there.
<kristianpaul> no no
<kristianpaul> i dont say we dont
<kristianpaul> just for the /. article
<lekernel> this time if some lamers vote it down again, they'll get it submitted 10 times or so before I give up :-)
<kristianpaul> tries to remenber his /. account password
<mwalle> hi
<kristianpaul> hola
<wpwrak> lekernel: what's not so good about your slashdot story is that it's merely an announcement of an event months into the future. there should be a connection to something that's happening now or in the immediate future. e.g., "last call for schematics review"
<wpwrak> lekernel: if you think the long-term announcement itself is also important, you could bundle it with some short-term item, even if minor. e.g., "new firmware now with full ethernet and tcp/ip support" or "ten new ''patches''" (then explain why this is not the kind of patch readers will usually expect) and then sneak in the long-term announcement somewhere later in the story