<wpwrak>
from the description, it may just be PWM+FET
<DocScrutinizer>
well, that circuit is nothing else
<DocScrutinizer>
unless you want to spoil your efficiency with a series-R you'll always need a schottky diode (or seconf FET) and a choke
<wolfspraul>
should I support him with a small run and opening up the design?
<wolfspraul>
I will find out more data points first :-)
<wolfspraul>
wpwrak: rc4 related question - can Adam start with the design verification of the new gate/4.4v reset circuit?
<wolfspraul>
we have sold over 30 rc3 already, not bad :-)
<wolfspraul>
one open question was the CE0/WE# pullup, my understanding is that you already verified that at least CE0 does no harm?
<wolfspraul>
even if it doesn't help much, should we still add it?
<whitequark>
maybe someone knows: what will happen if I accidentally swap the wires of an LVDS pair? will it explode? will it work?
<wolfspraul>
the one big open question about rc4 for me is whether we should change the VGA connector to DVI-I
<wolfspraul>
if we do that, we have to change the acrylic side panel, we need to source a DVI-I to VGA adapter cable
<wolfspraul>
the box printing also needs to be updated then
<wolfspraul>
we need to decide whether we want dual-link or not
<wolfspraul>
possible reasons to not want it:
<wolfspraul>
1. difficult to route the wires space-wise
<wolfspraul>
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)
<wolfspraul>
actually it could be a nice way to get wires out, for hacking purposes :-)
<wolfspraul>
so anyway, that's the only big open question
<wolfspraul>
dvi-i now or stay with vga...
<zrafa>
after hellow world with CMD bit of ubb today I will try to have CLK = 0 and CMDÂ Â = 1 via MMC
<kristianpaul>
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
<zrafa>
no idea how to check with scope yet. I took the scope and it is next to me
<zrafa>
sleeping :)
<kristianpaul>
and others i had talked about M1 and hhdl
<wolfspraul>
kristianpaul: what do you want to leave out? describe the product to me that you would like to buy
<kristianpaul>
a M1 with no VJ accesories, no VGA and better exp bus (more pincs and dedicated clock lines)
<kristianpaul>
no case either at least with your prices ;)
<kristianpaul>
ot make that an option
<kristianpaul>
i do wonder if that can reduce price at least up to 200usd?
<wolfspraul>
ok, one by one
<kristianpaul>
:)
<wolfspraul>
for "better exp bus", I asked many times but got very little feedback still
<kristianpaul>
*g*
<wolfspraul>
please help us by clearly making some suggestions what that 'better exp bus' would be
<wolfspraul>
specifically
<wolfspraul>
by definition a perfect 'expansion bus' is hard
<kristianpaul>
sure
<wolfspraul>
because you don't know what the expansion will be
<wolfspraul>
:-)
<wolfspraul>
but just saying "better" doesn't help much either :-)
<wolfspraul>
you are probably one of the guys with the most thinking into the expansion bus by now, next to Sebastien or Werner
<kristianpaul>
but double the number of pins and adding at least two dedicated pins for clocks sounds better?
<wolfspraul>
specifically
<wolfspraul>
need a patch
<wolfspraul>
:-)
<wolfspraul>
please understand how small our community is
<kristianpaul>
sure :)
<wolfspraul>
you are holding prime knowledge in your brain :-)
<kristianpaul>
yes
<wolfspraul>
I need an exact schematic diff
<wolfspraul>
which pin do you want to go where
<wolfspraul>
and how do we preserve hardware compatibility with the expansion header we have now
<wolfspraul>
so "better expansion bus" - yes, I'm very interested
<wolfspraul>
always was
<wolfspraul>
but what is 'better'? :-)
<wolfspraul>
you tell me
<wolfspraul>
I think we should preserve compatibility with our current header
<kristianpaul>
ok, i got your idea
<wolfspraul>
did we change the expansion header between rc2 and rc3?
<kristianpaul>
ha, easy if i drop VGA i have some "clock dedicated" pins from there, problem solved ;) (kidding)
<wolfspraul>
I thought there was a change somewhere
<kristianpaul>
dont remnber i dint read too much about rc2 at that time
<wolfspraul>
ok let me check that now, in the PDF schematics...
<wolfspraul>
what do you mean with "no vga"?
<kristianpaul>
remove vga related layout and components from the design
<wolfspraul>
don't understand
<wolfspraul>
why that?
<wolfspraul>
what's the display output then?
<wolfspraul>
ok I checked the history of J21, the current expansion header
<wolfspraul>
looks like it is unmodified between rc2 and rc3 - good
<wolfspraul>
I think we should preserve that J21, or at least mechanical and electrical compatibility with it
<wolfspraul>
if you have ideas how to improve J21, add to it, add a second one, etc. please specify them clearly
<kristianpaul>
ok
<wolfspraul>
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 :-)
<wolfspraul>
I think it's already clear there cannot be the perfect expansion header
<wolfspraul>
by definition
<wolfspraul>
expansion expands into the unknown
<kristianpaul>
sure
<wolfspraul>
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.
<wolfspraul>
one thing we can do is to maintain stability for the expansion header we have now
<wolfspraul>
compatibility
<DocScrutinizer>
heh
<wolfspraul>
so if anybody makes a board or connector for that, they can carry it forward
<wolfspraul>
kristianpaul: please explain 'no vga', I still don't get it
<wolfspraul>
you mean an m1 without any display?
<kristianpaul>
yes
<kristianpaul>
or at least thinking about not populate some components in current PCB (DMX, MIDI, Video-in, DAC)
<kristianpaul>
My first concern is price, features could get done next :)
<kristianpaul>
But i do understand there is few people, and will consider a patch before i talk about (will be nice if) features again.
<wolfspraul>
nah talk is better than silence
<wolfspraul>
I just want to move from talk to action
<wolfspraul>
and that requires more specifics
<wolfspraul>
look at J21, think about it :-)
<wolfspraul>
as far as I know nobody right now uses this header
<wolfspraul>
we don't need to maintain compatibility with something that doesn't exist
<DocScrutinizer>
you know you don't want *me* to do that ;-D
<wolfspraul>
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
<DocScrutinizer>
anyway not populating things for price cutdown doesn't make sense on a batch that small
<DocScrutinizer>
what's J21? VGA standard plug?
<kristianpaul>
no VGA, just a expastion header
<kristianpaul>
let me show  a pic
<DocScrutinizer>
aah
<zrafa>
DocScrutinizer: how the price could be reduced in some product like MM?
<zrafa>
DocScrutinizer: sorry for the tooo general question
<DocScrutinizer>
I'm not the business dude, but I think fist you have to look closely at where yur money goes right now
<kristianpaul>
i see that one thing looks constant for the run is SMT price
<wolfspraul>
I don't think leaving out chips makes much difference
<wolfspraul>
the best is to keep 1 unified product, and increase the quality, manufacturability (yield) and volume of that solution
<wolfspraul>
if anybody disagrees - go manufacture yourself, all files are open :-) like kristianpaul did with his case, for example
<kristianpaul>
*g*
<wolfspraul>
our product is already crazy cheap
<wolfspraul>
which is good
<wolfspraul>
and we will drive it down further
<wolfspraul>
but just above committing suicide
<wolfspraul>
there is a reason you will never find a new unusual product like this for such a price
<wolfspraul>
nobody is crazy enough and has the capabilities to do it
<wolfspraul>
for those that prefer to work with dev boards full of bugs that will never be fixed - go ahead :-)
<wolfspraul>
it's funny that over the years I noticed a dev board pattern
<wolfspraul>
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
<wolfspraul>
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)
<wolfspraul>
interesting, eh? :-)
<wolfspraul>
so my focus is on making rc4 as good as possible now
<wolfspraul>
first the reset ic / nor corruption improvements, then other little things we learnt in rc3
<kristianpaul>
i donk think they remenber the word subsidized
<wolfspraul>
yield and manufacturability must go up
<wolfspraul>
just full power improve everywhere ;-)
<wolfspraul>
kristianpaul: please help with specific ideas for better expansion header(s)
<kristianpaul>
Okay
<DocScrutinizer>
kristianpaul: sorry, I wouldn't know how to use that
<kristianpaul>
I do np :)
<DocScrutinizer>
(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
<DocScrutinizer>
)
<kristianpaul>
ahh, i tought you mean about J21 ...
<DocScrutinizer>
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
<DocScrutinizer>
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)
<DocScrutinizer>
if you use 1.2mm holes then there are even plugs that could plug in
<DocScrutinizer>
at least I think I've seen such plugs
<DocScrutinizer>
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)
<DocScrutinizer>
wolfspraul: toldya you don't want me to look at it ;-DÂ Â Whoever is your layouter, will hate me forever for this suggestion
<DocScrutinizer>
that'S what I thought, PSU aka regulator
<DocScrutinizer>
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
<DocScrutinizer>
screwing both to the case inevitably introduces mech tension to the PCB, even without somebody jogging the plugs in those receptacles
<DocScrutinizer>
aah wait, VGA has no case-mount
<DocScrutinizer>
though it probably better had
<wpwrak>
wolfspraul: (WE#/CE0) i've tried WE#. does no harm, correct. may help a little. data is a still a bit foggy.
<wpwrak>
zrafa: (CLK/CMD via MMC) great !
<wpwrak>
(exp bus) extension north is probably hard. must be a busy area.
<wpwrak>
but yes, the rest of the surface is pretty much covered :)
<wpwrak>
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"
<zrafa>
wpwrak: my problem is the RON :)
<zrafa>
wpwrak: so far, the level of RON I drunk is okey to work yet
<zrafa>
wpwrak: but i have the bottle near
<zrafa>
and there is coca yet
<wpwrak>
zrafa: ;-)))
<zrafa>
we will see how long
<zrafa>
I will have energy and patience for this task
<wpwrak>
try increasing the coke to rum ratio. then you'll last longer :))
<zrafa>
wpwrak: I have understood some important bits so I think that I did some advance at least
<wpwrak>
kewl !
<wolfspraul>
we can remove the J3 audio codec expansion header, I think
<wolfspraul>
wpwrak: do you want Adam to help with some design verification?
<wolfspraul>
or should he wait a little longer because it overlaps with your nor tests?
<wolfspraul>
Adam is still busy with rc3
<wolfspraul>
but at some point I want to move forward to rc4 with all resources I have
<wpwrak>
hmm, i have to get him a labsw. he has a lot more boards to play with :)
<wolfspraul>
that's such a useful board, maybe we just make a small run :-)
<wolfspraul>
and give away to some of our trusted core qi hackers
<wpwrak>
(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%.
<wolfspraul>
I want to accelerate
<wolfspraul>
so that's another idea
<wolfspraul>
quick labsw run
<wpwrak>
to make up for the 50%, it has now blown up flickernoise :)
<wolfspraul>
so the next for you is to also try CE0 ?
<wolfspraul>
and the gate and 4.4v reset ic?
<wpwrak>
yup, in that order
<wolfspraul>
I would just make all those mods and once and see whether the corruption is gone for good :-)
<wpwrak>
the problem is that i still seem to have external factors. maybe i just need more cycles to exorcise them, but maybe not
<wolfspraul>
should we include leds for ports in rc4?
<wolfspraul>
Sebastien is traditionally a bit reluctant about leds
<wpwrak>
ah ? how come ?
<wolfspraul>
and I don't know how many free fpga pins we actually have left
<wpwrak>
a lot, i think :)
<wolfspraul>
I vaguely remember roh proposing something along those lines many moons ago
<wpwrak>
see page 3 of the schematics
<wolfspraul>
roh suggested 4 leds in the corners, for illumination effects
<wpwrak>
heh :)
<wolfspraul>
I am fine with all this, leds for ports, leds for corners, etc. as long as nobody feels the product is being ruined
<wolfspraul>
and if there are free pins in the fpga, its' probably better to move them somewhere rather than let them die under the bga
<wpwrak>
not sure how constrained the board is with regard to the routing, though
<wolfspraul>
that's assumign there are no routing problems...
<wolfspraul>
sure, but first we need to define what we want
<wolfspraul>
another thing is the need of the metal sheet at the bottom side
<wolfspraul>
with every layout change and run we loose a chance to remove the need for it, assuming our tests are regression-safe
<wpwrak>
(sheet) do you know why specifically it's needed ?
<wolfspraul>
sort of
<wolfspraul>
I stood right there when the test failed, so I can describe
<wolfspraul>
we put a thin large metal sheet on the test table
<wolfspraul>
then on top of that a plastic insulation layer
<wolfspraul>
on top of that we put the assembled M1 (in acrylic case)
<wolfspraul>
we let M1 run
<wolfspraul>
now we induce a 6kV discharge into the metal
<wolfspraul>
the metal sheet
<wolfspraul>
what happens is that there are some visual corruptions in the rendering
<wolfspraul>
after 2 or 3 such shots, m1 just freezes or goes dark
<wolfspraul>
if we turn the m1 upside down, the test passes
<wpwrak>
funny :)
<wolfspraul>
so it's some field that goes through the insulation plastic and acrylic into the pcb
<wolfspraul>
if the distance is a bit more (such as when m1 is upside down), m1 keeps running
<wolfspraul>
but if the pcb is only maybe 1 cm or so away from the metal, maybe it corrupts memory
<wolfspraul>
memory corruption was Sebastien's wild guess from seeing the behavior
<wolfspraul>
the problem is to identify the 'sink'
<wolfspraul>
would be time consuming
<wpwrak>
it may be hard to reproduce, too
<wolfspraul>
so we just added this metal sheet between acrylic and pcb, and indeed that fixes the problem
<wolfspraul>
no
<wolfspraul>
definitely reproducible
<wolfspraul>
easy
<wolfspraul>
4kV also shows it
<wolfspraul>
we tested this many times
<wpwrak>
ah, good.
<wolfspraul>
this 6kV shot creates some field
<wolfspraul>
the field enters the pcb and corrupts maybe the memory
<wolfspraul>
the field gets a lot weaker with distance
<wpwrak>
DocScrutinizer51 probably knows a lot about EMI :)
<wpwrak>
yes, all that makes sense
<wolfspraul>
the way to fix this in the right way would be to find the exact 'sink', where the field/corruption enters
<wolfspraul>
but since we found the metal sheet workaround, we put that aside
<wpwrak>
not sure how to fix it, though. perhaps just a continuous ground plane at the bottom would do the trick
<wolfspraul>
now, with every layout change we have a chance to try something
<wolfspraul>
if we are sort of sure we don't introduce regressions, there are almost no costs to that
<wolfspraul>
there are lots of ground planes already
<wolfspraul>
but I don't know the exact details of the planes, vias, etc.
<wolfspraul>
if we could remove the neet for the metal sheet, that would be a big improvement in terms of manufacturability and cost
<wpwrak>
the bottom has many split planes
<wpwrak>
so field goes into the comes out through the other. current flows between.
<wpwrak>
is the metal sheet so expensive ?
<wolfspraul>
is it easy to make a change that might help
<wolfspraul>
or risky?
<wolfspraul>
it's very labor intensive
<wolfspraul>
and it looks bad too
<wolfspraul>
that metal sheet plus insulation layer alone is probably 30% of roh's work
<wolfspraul>
the next big thing are the buttons
<wolfspraul>
another 30%
<wolfspraul>
the entire rest is 40% of the work
<wpwrak>
was that testing done after or before we shorted all those chokes ?
<wolfspraul>
all my guess, roh can feedback if I'm wrong
<wolfspraul>
shorted what?
<wolfspraul>
maybe it would also help if we moved some of the stuff on the bottom side to the top?
<wolfspraul>
although there's probably a reason it's there...
<wolfspraul>
yes I saw that pic already :-)
<wpwrak>
(shortened) the Ls that "connected" ground planes.
<wpwrak>
(but left all the spikes to go through the chips, making them rather unhappy)
<wolfspraul>
you mean L3 and L19
<wolfspraul>
testing was done before that
<wpwrak>
yes, probably. don't remember the numbers.
<wolfspraul>
if Joerg has any ideas what low-risk improvements to try about this ESD problem, great
<wpwrak>
could be that L3 and L19 fixed that issue as well
<wolfspraul>
that would be great
<wolfspraul>
but I won't hold my breadth, this 6kV thing looked like a bomb
<wolfspraul>
can those 2 small fixes really help? I don't know
<wpwrak>
(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)
<wpwrak>
these 2 small fixes aren't so small when you consider what they do ;-)
<wolfspraul>
we have a relatively good feeling saying that the ESD shot created a memory corruption
<wolfspraul>
it was a software problem that eventually made it freeze
<wolfspraul>
that was our 'feeling' after repeating this a number of times
<wpwrak>
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.
<wpwrak>
could be. i don't know what things depend on these two chips. i think sebastien said one provides an important clock
<wolfspraul>
if I remember correctly, with 4kV it showed the problem only sometimes, maybe it took 2-3 shots
<wolfspraul>
at 6kV almost every shot brought it down a little more ;-)
<wolfspraul>
and at 8kV there was no hope
<wpwrak>
so if that gets upset, who knows what can happen. we already know that it can freeze the system.
<wolfspraul>
I think the test requires 4kV and 6kV is optional, or something like that
<wolfspraul>
there are ways to explain oneself out of this, but that was not our goal
<wpwrak>
if it's easy to do, i'd take a shot with the shorted Ls. they address quite specifically this problem domain
<wolfspraul>
anyway I just wanted to mention it again
<wolfspraul>
every relayout and run is a chance to improve this, as long as we are sure not to introduce regressions
<wolfspraul>
Sebastien would have to go back to the lab
<wolfspraul>
easy - yes, sort of. but still work.
<wolfspraul>
cost small, if any. that guy is very relaxed.
<wolfspraul>
but I cannot help with this, the lab is in Berlin
<wolfspraul>
how much does one of these esd guns cost actually?
<wolfspraul>
that particular test is very low tech
<wpwrak>
maybe sebastien can pay him a visit ?
<wolfspraul>
so unless there is a shortage of knowledge, it's easy to play with this at home :-)
<wolfspraul>
yes Sebastien could
<wolfspraul>
if he feels this is an important enough thing to work on
<wolfspraul>
maybe such a gun can be bought for 100 USD or so?
<wolfspraul>
then we need to document the test setup a little to not electrocute ourselves, then we can play
<wpwrak>
hmm, nothing under "esd *" from the usual suspects
<wpwrak>
the "now i have the gun. let's see if i can upset *this*." phase will be expensive, though :)
<wolfspraul>
not sure
<wolfspraul>
there are different levels of 'pass'
<wolfspraul>
the highest level is that it passes without any issues or interruption
<wolfspraul>
even then you have different strengths of shocks
<wolfspraul>
at some point everything goes down
<wolfspraul>
the second level is that it keeps running, but with problem
<wolfspraul>
third level is that it shuts off or reboots
<wolfspraul>
fourth level would be permanent damage, I guess :-)
<wolfspraul>
something like taht
<wolfspraul>
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
<wolfspraul>
since everything will fail at some point
<wolfspraul>
great leeway
<wolfspraul>
we could have left out that metal sheet and nobody would have noticed or cared or it most likely would ever have mattered
<DocScrutinizer>
mhm, and a 75kV electroshocker can easily take out of service every phonebooth and cigarette machine
<wolfspraul>
so when you have such a gun, you start with 2kV
<wolfspraul>
can test your household stuff a little :-)
<wolfspraul>
I bet [75kV]
<wolfspraul>
DocScrutinizer: did you read up on the test above?
<wolfspraul>
any ideas what we might improve in the board?
<DocScrutinizer>
improve for what? which test?
<wolfspraul>
phew :-)
<wpwrak>
(test your household stuff a little) yeah, that;s what i meant with the expensive part ;-)
<wolfspraul>
just above, a few lines
<wolfspraul>
wpwrak: yes but you start with 1kv, 2kv
<wolfspraul>
and then you slowly go up
<wolfspraul>
and as you go up, you will see when stuff starts failing
<wolfspraul>
I doubt the very first thing you see is a permanent damage
<DocScrutinizer>
ESD test? weardll, dunno the bo
<DocScrutinizer>
grr
<wolfspraul>
DocScrutinizer: I describe it again
<DocScrutinizer>
ESD test? well, dunno the board
<wolfspraul>
put metal sheet on table, put plastic insulation on top
<wolfspraul>
then Milkymist One, assembled in acrylic case, on top of that
<wolfspraul>
shoot 6kV into metal on table
<wolfspraul>
what we observed looked like a memory corruption
<wolfspraul>
m1 kept running, but with strange visuals
<wolfspraul>
when we turned the m1 upside down, it was stable
<DocScrutinizer>
not exactly a surprise
<wolfspraul>
in upside down, the pcb is about 3 cm further away from the metal that gets the shock
<wolfspraul>
when we put a metal insulation layer below the pcb, it was stable also with the pcb on the bottom
<wolfspraul>
so the order then was
<DocScrutinizer>
jep, or like 8 times further, I guess
<wolfspraul>
1. metal on table
<wolfspraul>
2. plastic insulation
<wolfspraul>
3. acrylic
<wolfspraul>
4. metal sheet inside case
<wolfspraul>
5. pcb
<wolfspraul>
the pcb was < 1 cm away from the metal that got the shock
<wolfspraul>
that was stable
<wolfspraul>
but when we remove #4, we get what looks like memory corruption
<DocScrutinizer>
yup
<wolfspraul>
for rc3, we kept the metal insulation layer inside the case, but it was a lot of hard work
<wolfspraul>
so we are thinking what long shots we can try in rc4, something with low risk of bad side-effects, to improve this
<wpwrak>
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.
<DocScrutinizer>
well, improve the metal sheet design to reduce work with it
<wpwrak>
make a metal case ;-)
<wolfspraul>
"improve the metal sheet design" ?
<wolfspraul>
it's a lot of work no matter which way you turn it
<wolfspraul>
and only needed because the pcb itself is not designed to keep the esd impact away
<wolfspraul>
which is most likely possible in some way
<wpwrak>
why is it so much work ? that's what i don't quite get
<wolfspraul>
because it is
<wolfspraul>
manual labor
<DocScrutinizer>
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
<wolfspraul>
not just running a software loop a couple times more :-)
<wolfspraul>
metal needs to be sourced, cut
<wolfspraul>
holes need to be drilled
<wolfspraul>
insulation layer needs to be glued on it
<wolfspraul>
that thing along was 30% of the workload for the entire rc3 cases
<wolfspraul>
alone
<wolfspraul>
and it's completely unnecessary
<DocScrutinizer>
no, it's not
<DocScrutinizer>
a metal shielding against ESD is mandatory quite frequently
<wolfspraul>
you think there is no way to get rid of it?
<DocScrutinizer>
probably not
<wolfspraul>
my guess is that it's a kludge only needed because we combine a lust of meeting standards with lack of resources :-)
<DocScrutinizer>
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
<wolfspraul>
no
<wolfspraul>
not middle of the board
<wolfspraul>
I described the test setup already twice now :-)
<DocScrutinizer>
isn't the source metal plate in parallel to the PCB?
<wolfspraul>
yes
<DocScrutinizer>
so discharge can hit middle of PCB
<wolfspraul>
the spark was applied to the side of the metal plate
<DocScrutinizer>
in real life even more likely to happen
<DocScrutinizer>
that's irrelevant
<DocScrutinizer>
you could replace the metal sheet inside by a wire going 5 times zickzack across the plastic case bottom
<DocScrutinizer>
faraday cage
<DocScrutinizer>
or more like lightning protector
<DocScrutinizer>
get 5mm alu sticky tape on endless reel
<wolfspraul>
ok I am pretty sure we could make layout changes to the pcb that would let us pass this test
<DocScrutinizer>
you can't, basically
<wolfspraul>
add another layer to the pcb to just move the metal to that layer
<DocScrutinizer>
?
<wolfspraul>
no?
<wolfspraul>
metal layer is metal layer
<DocScrutinizer>
the problem is your chips aren't *under* that layer
<wolfspraul>
yes they are above
<wolfspraul>
just like with the metal sheet we added now
<DocScrutinizer>
you don't need a metal sheet, you just need a wire at same location
<wolfspraul>
alright we don't get many practical ideas out now :-)
<DocScrutinizer>
connect that wire to central GND point (usually minus of power supply, sometimes EE decides to have GND of input as central GND point)
<wolfspraul>
maybe someone buys a gun, then we can more easily play with it
<wolfspraul>
and maybe we can find the area of the board where it enters, and a simple metallic tape at that location may be enough?
<wolfspraul>
I don't know
<DocScrutinizer>
run a gnd trace all along the sides of your PCB
<wolfspraul>
I'm sure there are better ways to improve it than what we have in rc3
<wolfspraul>
[gnd trace along sides] ok, we can ask around and see whether someone thinks this is a bad idea
<DocScrutinizer>
the point where it enters is irrelevant if you catch the discharge spark halfway at the location where your metal sheet is now
<wolfspraul>
we have a lot of space on the bottom. actually I'm wondering why we can't move all components to the top.
<wolfspraul>
spark?
<wolfspraul>
the spark enters the metal sheet far away, say 30cm or so away from the M1
<DocScrutinizer>
wolfspraul: what is your take on what actually happens to the electrons after they entered the source metal plate ?
<wolfspraul>
my definition of 'spark' may be a little simplistic, I thought it's just the thing you can see...
<wolfspraul>
sure the metal conducts
<wolfspraul>
and then there's the plastic insulation on top of it
<DocScrutinizer>
it will go to GND one way or another
<DocScrutinizer>
one way was directly to some metal of the desk it sits on
<DocScrutinizer>
another was to cable (e.g vga, or power, or usb whatever) straight thru the cable's isolation
<DocScrutinizer>
yet another was straight thru the layers 2) and 3) missing 4) metal sheet into a chip on 5) PCB
<wpwrak>
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 :)
<DocScrutinizer>
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
<DocScrutinizer>
...unless you got either a metal sheet or a few wires there to form a faraday cage
<wpwrak>
perhaps replacing the M1's bottom acrylic with metal would help. a tad messy to produce in low volume, though.
<wpwrak>
maybe kristianpaul can find a cheap place with a CNC mill :)
<wolfspraul>
no no
<wolfspraul>
those are separate solutions
<wolfspraul>
of course we can build a faraday cage
<wolfspraul>
we can build a metal case
<wolfspraul>
people use copper spray on the inside of plastic parts
<wolfspraul>
and so on
<wolfspraul>
but that is not what I am after right now
<wolfspraul>
I am trying to design the pcb better
<DocScrutinizer>
probably two stripes of metals sticky tape across the diagonals of the arcrylic wil suffice if you connect them to GND
<wolfspraul>
or 'as good as possible'
<wpwrak>
that would be a partial metal case - just change the bottom plate, keep the rest of the concept
<wolfspraul>
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
<wpwrak>
if you want a quick fix, see if it's already fixed :)
<wolfspraul>
just think about any modern smartphone, how thin they are, how much stuff is inside - how do they pass those tests?
<wolfspraul>
our problem if anything are our minuscule resources
<wpwrak>
DocScrutinizer: do you know how much such ESD guns / ESD simulators cost ?
<wolfspraul>
we cannot just throw 100k USD research money at this to make it 'go away'
<DocScrutinizer>
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
<wolfspraul>
well I dout we can say our pcb right now is 'perfect'
<DocScrutinizer>
wpwrak: no, but I guess they are rather cheap
<wolfspraul>
especially when you haven't looked at it in detail yet (not saying you should, just pointing out a hole in your logic)
<wolfspraul>
my initial point was innocent
<DocScrutinizer>
it's basically just a capacitor that gets charged to a defined voltage
<wolfspraul>
I wanted to remind myself and others that every new run is a chance to get rid of the need of the metal sheet
<wolfspraul>
which would make roh happy :-)
<wpwrak>
do you actually need the isolation on the metal sheet ?
<wolfspraul>
that's to avoid that the metal bends and shorts something on the bottom side of the pcb
<DocScrutinizer>
wolfspraul: we for sure can improve a few things on PCB, but that won't solve the problem, just reduce it
<wolfspraul>
especially after someone unassembles and reassembles the case
<wpwrak>
yes .. but is that likely to happen ?
<wolfspraul>
reduce it may be enough to pass the test
<wolfspraul>
no it's not likely to happen
<wpwrak>
okay, good
<wolfspraul>
we could have left out the entire metal sheet and just bend the rules like 99% of other commercial companies would have :-)
<wolfspraul>
and 100% of Chinese
<wolfspraul>
maybe that's why they are so successful :-)
<wolfspraul>
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
<wolfspraul>
then everything is 'perfect'
<wolfspraul>
and the metal sheet can be removed
<wolfspraul>
it's a waste of money and resources and distraction anyway
<DocScrutinizer>
another suggestion: place some posts on gndplane that protrude way further than the sensitive parts next to them
<wolfspraul>
can you translate it down to my dumbness level?
<wolfspraul>
first idea - run a gnd trace around the outline of the board
<wolfspraul>
right?
<wolfspraul>
bottom side I guess? or bottom and top?
<DocScrutinizer>
right
<wpwrak>
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
<DocScrutinizer>
bottom and top, and connect to real GND only in one spot, which is the central GND spot
<DocScrutinizer>
yup, there've been those incredibly stupid chokes in GND
<wpwrak>
DocScrutinizer: GND around the PCB ... how does this mix with connectors that have metal at the edge ?
<wolfspraul>
no worries I can sleep great
<DocScrutinizer>
those are like building a parabolic dish for ESD
<wolfspraul>
I think one reason for the closedness in the hardware industry is that they really depend on hiding a lot of stuff :-)
<wpwrak>
(-:C
<wpwrak>
wolfspraul: you've heard it ;)
<wolfspraul>
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
<wolfspraul>
that combination leads to being stuck
<wolfspraul>
an ousider might call it stupid
<wolfspraul>
all Chinese will call it stupid
<wolfspraul>
:-)
<wpwrak>
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
<wpwrak>
all the rest is good design advice, of course
<wolfspraul>
this is actually a quality level that makes sense, I'm just saying in general we do have this mix sometimes
<wolfspraul>
"hey, I have found this law here, look, we have to do this and that"
<DocScrutinizer>
wpwrak: mix?
<wolfspraul>
then I ask around the industry, and nobody even knows the laws, and everybody is busy couting their profits and paying taxes and bribes
<wolfspraul>
just kidding
<wolfspraul>
back to making M1 the perfect ESD machine...
<wpwrak>
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 ?
<wpwrak>
maybe the answer is "the connector should go to common ground" :)
<DocScrutinizer>
errr
<wolfspraul>
hmm
<wolfspraul>
what does this translate to exactly on m1 then
<wolfspraul>
maybe we even have that already?
<wolfspraul>
and what about those "posts on gndplane that protrude further than the sensitive parts"
<wpwrak>
(posts) lightning rods :)
<DocScrutinizer>
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
<wpwrak>
(have that already) yes, maybe. now that the split ground planes have grown together again, we may indeed have that already
<DocScrutinizer>
(lightning rod) yeah, or simply electrolytic capacitors for example
<DocScrutinizer>
the aluminium case is on - usually?
<DocScrutinizer>
on minus*
<wolfspraul>
no aluminum case
<wolfspraul>
acrylic case
<DocScrutinizer>
electrolyt capacitors have no acrylic case ;-D
<wolfspraul>
ah sorry, lost the context
<DocScrutinizer>
wolfspraul: the whole point is to have the most protruding conducting parts be GND level
<wolfspraul>
ok
<wolfspraul>
but I don't know what that translates to in the m1 pcb :-)
<wolfspraul>
and unfortunately the layout files are in Altium format still
<wpwrak>
that would actually be the feet
<wolfspraul>
so hard to quickly converge around some specific small ideas now
<wpwrak>
yes, kicad when ? ;-)
<DocScrutinizer>
looking on an arbitrary PCB next to me I see most protruding parts being xtal, capacitors, a huge choke witj siferrite core
<wolfspraul>
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
<DocScrutinizer>
a photo of a real PCB would help better
<wpwrak>
wolfspraul: one thing that may help with interference hardening is to move long traces traces to an inside layer
<wpwrak>
e.g., the SDRAM address lines (those with the R7x and R8x resistors)
<wpwrak>
on the other side of the FPGA, there are also what's probably NOR lines with a similar pattern
<wpwrak>
interesting. the M1 schematics don't mention what value the series resistors of the SDRAM have
<wolfspraul>
wpwrak: layout outsourced sounds so draconian
<wolfspraul>
I think we have moved way past that
<wolfspraul>
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.
<wolfspraul>
there are 2 layout personnel that by now are relatively familiar with the board's layout
<wolfspraul>
if we move to kicad, we loose the ability to get their feedback
<wolfspraul>
so I'm hesitating still
<wolfspraul>
can we import gerber files into kicad to transition the layout?
<wolfspraul>
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
<wpwrak>
yes, we have the gerbers. not sure it they're a nice way to get started, though
<wolfspraul>
for example the planned change from vga to dvi-i connector
<wpwrak>
e.g., you'd have difficulties making things "snap"
<wolfspraul>
especially if we go dual-link, we have a lot of new wires
<wolfspraul>
that would be done by the same layout people as before, using the Altium files
<wolfspraul>
Anson Lin and Vera Cheng
<wolfspraul>
trying to convert them to KiCad makes no sense, that will cost us more than not asking them to help at all
<wpwrak>
;-)
<wpwrak>
it's not something you do in a weekend anyway
<wolfspraul>
yes we just have to be realistic here and choose the best path forward for the product
<wpwrak>
you also need to update your components libs, footprints, etc.
<wolfspraul>
everything stays 100% open anyway
<wolfspraul>
the files
<wolfspraul>
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)
<wolfspraul>
so...
<wolfspraul>
do we have some actionable rc4 esd ideas now?
<wolfspraul>
I'm still not 100% clear
<wolfspraul>
I can point Adam to this chat who can in turn point Anson and Vera to it
<wolfspraul>
most likely nothing will happen then :-)
<wpwrak>
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.
<wolfspraul>
yes but we are talking about rc4 now and I want to upgrade it with all the nice things we learnt in rc3
<wolfspraul>
M1 rc4
<wolfspraul>
the esd issue just came back to my mind
<wolfspraul>
since I think if we are lucky we can get rid of the metal sheet without much effort
<wpwrak>
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
<wolfspraul>
with some luck...
<wpwrak>
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 ?
<DocScrutinizer>
a lil bit, depends on how much it's coupling capacitively to GND vs to trace
<wpwrak>
DocScrutinizer: yeah, the area should be considerably larger than the trace. otherwise you'd indeed just have added one more trouble amplifier ;-)
<wpwrak>
there should be simpler ones, though. hard to google.
<wolfspraul>
DocScrutinizer: thanks a lot for your feedback!
<wolfspraul>
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 ;-)
<wpwrak>
yeah, seems that the ESD simulators you can actually find a price for are all quite expensive
<wpwrak>
probably > 50% going into insurance :)
<wolfspraul>
why that expensive?
<wolfspraul>
with my China brain I'd give it 100 USD
<wolfspraul>
(small) electrocution risk included, of course
<wolfspraul>
I shall add it to my sourcing list, next time I'm near a market... :-)
<wpwrak>
you should visit the market and see what you find.
<wpwrak>
exactly ;-)
<wolfspraul>
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
<wolfspraul>
I wouldn't value my own life at 10 USD or so, fair Chinese market value
<wpwrak>
(gloves) ;-)))
<wolfspraul>
just judging from all the most basic things that are falling apart in my household
<wolfspraul>
amazing how many things one can get wrong
<wolfspraul>
really
<wpwrak>
how many electrical fires did you have to put out so far ?:)
<wolfspraul>
so yes, seriously. only with a glove I can trust, sourced from a foreign brand. I am not kidding.
<wolfspraul>
well
<wolfspraul>
they know each other
<wpwrak>
so the glove will be more expensive than the ESD critter ;-)
<wolfspraul>
so when I turn on the mini oven and microwave together, the fuse jumps out
<wpwrak>
that's a good start :)
<wolfspraul>
because the cabling and pretty much everything is typically so crappy, you work with small fuses just in case
<wolfspraul>
hopefully the fuses are made in Japan
<wolfspraul>
I am sure one can get that wrong too
<wolfspraul>
fine but I would insist on such a glove
<wolfspraul>
using a made in China ESD gun
<wpwrak>
so not 100% adapted to chinese standards yet ;-)
<wolfspraul>
I take enough risks even that way, it could explode etc.
<wolfspraul>
best would be to hire a Chinese proxy worker
<wolfspraul>
remote hands, literally
<wolfspraul>
:-)
<wpwrak>
;-))
<DocScrutinizer>
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)
<DocScrutinizer>
idly ponders to suggest revamping a 20ct piezo gas lighter
<wolfspraul>
DocScrutinizer: yes, thanks for the notice :-)
<DocScrutinizer>
probably better meets the specs than a chinese ESD gun ;-D
<wolfspraul>
maybe there really are no Chinese ESD guns, and that's why the foreign ones are still expensive
<wolfspraul>
even the Chinese may be unable to sustain the personnel losses from using their own ESD guns :-)
<DocScrutinizer>
fair assumption
<wolfspraul>
I wouldn't be surprised the least if that were actually the case
<wolfspraul>
I have made stranger realizations in China...
<DocScrutinizer>
also there's simply no market for such a device
<wolfspraul>
because nobody cares about ESD? :-)
<wolfspraul>
he he
<wolfspraul>
we become the cynicist club here...
<wolfspraul>
it's not that bad - I will keep my eyes open
<DocScrutinizer>
as chinese don't care at all about ESD tests, and export won't be interested for know reasons
<wolfspraul>
actually in Taiwan I've heard taking those shots is not that bad
<wolfspraul>
they use it as some kind of mutprobe
<wolfspraul>
when you get a strong esd discharge at home, how strong is that compared to a 4kV shot from a gun? don't know...
<wolfspraul>
of course if something is wrong with the gun, all bets are off, I guess :-)
<DocScrutinizer>
probably quite similar, as those 4kV got picked to simulate exactly that
<DocScrutinizer>
there's even the HBM, human body model. taletelling, no?
<DocScrutinizer>
>>Guidelines and requirements are given for [...] types and points of discharge on the "victim" product...<<
<DocScrutinizer>
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
<wolfspraul>
yes
<DocScrutinizer>
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
<DocScrutinizer>
additional benefit: proven small risk of auto-electrocution
<DocScrutinizer>
:-)
<DocScrutinizer>
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
<DocScrutinizer>
ooh, already getting late over there :-D
<wpwrak>
the spacers have some fancy grounding ;-) into adjacent split grounds. i wonder if this is really such a good idea ...
<wpwrak>
(labsw) there's nothing power supply in there. all it does it switch ;-)
<wpwrak>
s/does it/does is/
<wpwrak>
and it switches slowly
<wpwrak>
realized that i''ll have trouble sleeping when the power-cycling tests are done. i'll miss the clicking of the relays.
<wpwrak>
s/realized/realizes/
<wpwrak>
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
<wpwrak>
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
<wpwrak>
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.
<wpwrak>
and there's a 1% chance of hitting it within only 35 cycles. and so on.
<wpwrak>
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
<apink>
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.
<apink>
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.
<jow_laptop>
"/etc/init.d/start enable" should create the symlink accordingly
<apink>
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.
<jow_laptop>
this is usually cleaner as it also treats the START= variable correctly
<apink>
jow_laptop:  Thanks.  I will change the wiki.
<zear>
are people responsible for ben liballegro port in here?
<whitequark>
wpwrak: hi
<whitequark>
I've tested the board--looks like the boost and logic parts of it work, but now there's another problem
<whitequark>
there is a backlight power converter in the LCD screen, it is powered by 12V 300mA
<whitequark>
we have a 12V converter module (sealed and so on)
<whitequark>
rated 2A
<whitequark>
on the power on, the power converter does "bzzzZzZzZ(khrzzkhrzzkhr){10}zz.", and, during that, the voltage at converter output is ~6.5V
<whitequark>
after it silences out (it turns off at overcurrent), the voltage is ~7V
<whitequark>
the lamp emits only a very dim light during the bzzzz'ing
<whitequark>
what can be wrong?
<whitequark>
maybe you have an idea or two :)
<whitequark>
oh, it's rated 500mA, and 2A is the maximal peak current
<wpwrak>
should still be enough. during the test, is is loaded ?
<whitequark>
hm
<whitequark>
the lamp is connected, and the 12V converter is attached to HV converter before I turn everything on
<whitequark>
I guess it is, then
<wpwrak>
odd then. well, check the current ...
<wpwrak>
(input current first)
<whitequark>
hmmm
<whitequark>
it now "works" in a different pattern
<whitequark>
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)
<whitequark>
the lamps glow very dim (but they definitely do)
<whitequark>
and the current is 170mA
<whitequark>
@5V
<whitequark>
the output voltage is 5.5V, and the input is 4.63 (down from 4.92 normally) V
<whitequark>
I guess it's because I am powering it from a different (USB) power source
<whitequark>
I've tried to attach a spare lamp I had lying somewhere
<whitequark>
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
<wpwrak>
hmm, odd. dunno. maybe a bad module ?
<whitequark>
it worked in the notebook
<whitequark>
or do you mean the 12V boost one?
<whitequark>
the noise is emitted by HV coil. neither it nor the controller build up any heat
<whitequark>
even if it is the inverter, they cost near to nothing
<whitequark>
according to leaked FCC test results, it's 1.5mA@1.4kV
<whitequark>
and the input current is 33mA
<whitequark>
hm.
<whitequark>
wait, what?
<whitequark>
does it have some kind of perpetuum mobile inside? :D
<whitequark>
I've powered it off a SLA accumulator with the same result
<whitequark>
it's quite discharged, through
<wpwrak>
so what does that have to do with your 12 V converter ? it this a third converter in your system ?
<whitequark>
fourth, actually
<wpwrak>
i somehow wonder if it wouldn't have been easier to just get some cheap tablet and remove the case ;-)
<whitequark>
I have a board (yes, that's mine too) which charges Li-Poly accumulators and converts their whatever voltage to 5V
<whitequark>
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
<whitequark>
there is a boost 5V->12V which I've already described
<whitequark>
and 12V->HV which powers the backlight
<whitequark>
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?
<whitequark>
that one.
<whitequark>
so, no switching converters there :D
<wpwrak>
sounds massively complex :)
<whitequark>
not any more complex than a random netbook
<whitequark>
my one has IIRC five converters
<whitequark>
not counting the one in power supply
<wpwrak>
yes. but a netbook can probably do a bit more, no ? :)
<whitequark>
yes, taking a cheap tablet and removing the case is MUCH easier
<whitequark>
but it is also much less fun
<wpwrak>
heh :)
<whitequark>
the resulting "thing" will be rougly equivalent by functionality to any ARM netbook
<whitequark>
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
<whitequark>
quite in the spirit of OSHW
<whitequark>
(ahem)
<whitequark>
I'll happily publish eveything under WTFPL, but I doubt that some brave one exists which will try to replicate this design
<wolfspraul>
I was thinking about building a portable (luggable) Milkymist One case :-)
<whitequark>
also, it is quite dependent on the scrap parts I (and my friend who wants that) had lying around
<wolfspraul>
we can make a competition whose portable computer is heavier and bulkier...
<whitequark>
current "motherboard" we use runs Linux on some (I don't quite recall which) high-end Cortex-A
<wolfspraul>
do you have some pictures?
<whitequark>
yeah, quite a lot of them. I'm planning to write a small article on making the board
<whitequark>
I don't currently have any for the whole device, sorry
<whitequark>
forgot to take them
<whitequark>
wait a sec, I'll upload them
<whitequark>
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
<whitequark>
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
<wolfspraul>
ok nice! I need to learn more about your project for better overview...
<whitequark>
not sure if everyone on this channel wants to hear about it
<whitequark>
I'll PM you
<wolfspraul>
why not?
<whitequark>
ah okay
<wolfspraul>
please keep the channel posted :-)
<whitequark>
so, the ultimate goal of this project is a notebook made from as many perfectly known parts  as it is possible
<whitequark>
*not notebook, but a tablet
<whitequark>
the notebook was a year ago :)
<whitequark>
the core of it will be a high-end ARM like Cortex-A
<whitequark>
with a lot of memory and Linux on-board
<wolfspraul>
I will follow more closely
<wolfspraul>
gotta run now, bbiab
<whitequark>
hmm
<whitequark>
should I wait for him or just leave that in the logs?..
<whitequark>
wpwrak: how would you design something netbook/tablet-like without a lot of switching power supplies?
<whitequark>
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
<whitequark>
and a li-po charger is a step-down converter too
<whitequark>
so, five at least
<kristianpaul>
ha, after all i discover a mprintf implementation inside gnsssdr.ru osgpa port to solve the unsigned issue fot the 16bits data
<kristianpaul>
so it can print signed :)
<kristianpaul>
wpwrak: yes i do have friends with CNC and better prices than when M1 case
<kristianpaul>
still waiting invitation for altium live so can get the viewer
<kristianpaul>
oh,  OsmocomGMR annonuce :)
<kristianpaul>
wpwrak: is okay to ignore that is still having 0.38% of write fails to the namuru core i ported to M1?
<kristianpaul>
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.
<wpwrak>
that's register writes ? failures sound like trouble ...
<kristianpaul>
control and status register.. i added some general porpuses there to run some basic test initially to measure troghput and later to verify writes
<kristianpaul>
and actually that may explain why some code dint worked in rtems but do i the m1 bios
<wpwrak>
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.