#qi-hardware IRC log for Sunday, 2011-04-03

kristianpaulwpwrak: I'm going to give a small talk to the local dorkbot people about copyleft hardware01:20
kristianpaulI will talk about nanonote, milkymist and wpan  (may be gps-sdr for get people interested on development too)01:21
kristianpaulI want talk about the part of the atena design in wpan01:21
kristianpaulIs okay said, it is a rev eng process coming for already similar products, and you developed the tools and integrated existent one as usrp2 in order to make that trial and error process easier?01:22
wpwrakkristianpaul: i didn't really reverse-engineer the antenna. i took this design: http://focus.ti.com/lit/an/swra117d/swra117d.pdf01:27
wpwrakkristianpaul: what i changed was the size. TI describe that the size depends on the PCB thickness, but don't explain how exactly it changes. (their design is for a 1.0 mm board, mine are 0.8 mm)01:28
wpwrakkristianpaul: finding the right size is what the experiments were for01:29
kristianpaulah, okay !01:29
wpwrakkristianpaul: i used the usrp2 basically as a spectrum analyzer. i didn't complete any software that talks directly to the USRP2 (there's that partial spectrum analyzer i did, but that doesn't produce correct results yet)01:31
wpwrakkristianpaul: instead, i used the gnuradio tool usrp2_rx_cfile.py to capture a transmission and then perform FFT (and some other filtering) on it01:32
wpwrakkristianpaul: so i integrated the USRP2 and an existing gnuradio tool into my test/experiment setup01:32
kristianpaulwpwrak: what about RF consideratios for board design, is it also documented on the aplication note you pointed to me?01:34
wpwrakkristianpaul: see also ben-wpan/usrp/sps/collect for collecting the traces, and ben-wpan/usrp/fft.c for the FFT. ben-wpan/usrp/sps/ has more scripts for visualization and such. they are what i used to generate http://downloads.qi-hardware.com/people/werner/wpan/20110303/01:36
wpwrakkristianpaul: (RF) a little. but most comes from http://www.atmel.com/dyn/resources/prod_documents/doc8092.pdf01:37
kristianpaulyes, i'm aware of FFT part01:38
wpwrakkristianpaul: plus a bit of googling around. see also ben-wpan/ecn/ecn0007.txt01:38
kristianpaulokay, software part is the implementation of MAC by bit banging RF CHip registers?01:38
kristianpaulone of the functions of software part*01:39
kristianpaulI just like to make clear how a "Wifi" chip differ from yours 802.15.4 one01:40
wpwrakkristianpaul: there are two sets of software: the tools in ben-wpan/tools/ and the linux stack. the linux stack uses the ieee 802.15.4 drivers and mac of the linux-zigbee project. i just made a few small corrections and added the platform-specific initialization (gpio setup and such)01:40
kristianpaulAnd the benefist in software01:40
wpwrakkristianpaul: the tools under ben-wpan/tools/ don't implement a proper mac - they just send "naked" frames without address fields or such01:41
wpwrakkristianpaul: well atrf-txrx, which is the most complex of the tools. the others have other roles, e.g., atrf-id just identifies the chip, atrf-rssi shows the signal strength (without actually receiving any data), and so on01:42
kristianpaulwpwrak: any wishlist for wpan thay you feel missed now, and wanted for future versions?01:57
wpwrakkristianpaul: better RF design testing. more compact (use a four-layer board with microvias). maybe better testability for atben (lacks an easy way to test the crystal). maybe antenna diversity. maybe an RF amplifier for range extension. find out if a dedicated MCU can be useful and act accordingly (or not).02:03
wpwrakkristianpaul: also, some real-life experience with wpan may add more items :)02:04
kristianpaul(real-life experience) agreed :-)02:08
qi-bot[commit] Ayla: The method FileLister::browse() now takes an optional boolean argument. http://qi-hw.com/p/gmenu2x/d82047010:03
qi-bot[commit] Ayla: If the "sections/" directory is missing, we create it as well as some default sections (settings, applications...). http://qi-hw.com/p/gmenu2x/8336c8310:03
qi-bot[commit] Ayla: The sections directories shall now be found under the user-specific directory. http://qi-hw.com/p/gmenu2x/114fe5910:03
qi-bot[commit] Ayla: The skin images will now be loaded using SurfaceCollection::getSkinFilePath(). http://qi-hw.com/p/gmenu2x/fe25cf310:03
qi-bot[commit] Ayla: Define a default wallpaper path, that will be chosen if no wallpaper is defined on the config. http://qi-hw.com/p/gmenu2x/301e16e10:03
AylaI'm looking for a picture I could use as the default wallpaper for gmenu2x for the nanonote10:21
wpwrakwolfspraul: so now the community news feature deep inside jokes ;-))10:36
wpwrakwolfspraul: not sure it you saw these:10:37
wpwrak| potential entries for the 04-04: 1) the ben-wpan samples http://lists.en.qi-hardware.com/pipermail/discussion/2011-March/007457.html10:37
wpwrak| the decision that tuxbrain will lead the production (and which may potentially have started already)10:37
wpwrakoops, let's try this again ...10:37
wpwrak| 2) the decision that tuxbrain will lead the production (order already issued)10:38
wpwrak| 3) that we have a kernel that allows atben to communicate via ieee 802.15.410:38
wpwrak| not sure if 3) is newsworthy yet. there are still a few more things missing before it's actually useful10:38
wpwrak| regarding 2), there's also the integrated process for producing fab files, but i haven't documented it yet. at its core is ben-wpan/makefiles/Makefile.kicad, which is semi-generic10:38
wolfspraulyes sure I saw it, thanks a lot10:43
wolfspraulno worries10:43
wolfspraulwpwrak: what is the deep inside joke?10:43
wolfspraulI just try to collect a few nice things...10:44
wpwrakwolfspraul: the money falling from the sky :)10:44
Action: kristianpaul at medellin11:01
wolfspraulwpwrak: ah. that may be subconsciousness :-)11:02
wolfspraulI just flipped through the mimi&eunice comics and liked that one...11:02
wpwrakit resonates rather strongly with current events ;-)11:03
kristianpaulI liked that comic too :-)11:10
wolfspraulok I think all sections except NanoNote are finished11:34
wolfspraulthis is what I'm talking about http://en.qi-hardware.com/wiki/Community_news_2011-04-0411:34
wpwrakwolfspraul: do the new visual patches have any images ?11:41
wolfspraulfbgrab (screenshot) is also just being added11:45
wolfspraulso there are few screenshots of m1 still11:45
wolfspraulbut that should soon improve :-)11:45
wolfspraulctrl-f12, done11:46
wpwrakaah, fbgrab. very important indeed !11:46
wolfspraulso I don't know whether we have screenshots, I didn't see any otherwise I would have included them11:46
wolfspraulone by one11:46
wolfspraulwe also have 05-01 news11:46
wolfspraulthe old way to take screenshots was only in qemu, afaik11:47
wolfspraulSebastien uploaded the 2 shots of his new color theme, not sure whether he took them in qemu or already with fbgrab11:48
wpwrakshould be easy to find out ;-)11:49
wpwrakhmm. maybe.11:54
wpwraklarsc: i just read about zram ... could this be something useful for our ben's poor little memory ?11:57
Aylayes, it works quite good12:04
wpwrakAyla: you've tried it on the ben ?12:07
kristianpaulwhere do you tested or saw it working Ayla ?12:07
Action: kristianpaul at hostel12:07
Aylait's enabled by default on opendingux12:07
Aylathe new linux kernel for dingoo a32012:07
Aylaso it should work quite good on ben too12:07
wpwrakAyla: how does the system's performance differ with/without it ?12:14
Aylawell, if it's not used, it does not eat any memory or processing power12:15
Aylain use, it uses some processing power to compress/decompress the data. However, it's still faster than swap on a flash device like SD12:16
wpwrakAyla: do you did notice a performance improvement ? i mean, not only on paper12:18
Aylayes, eduke32 is less laggy when using swap12:18
AylaI mean, zram swap over SD swa12:18
wpwrakgreat. that's a useful data point, thanks12:19
wpwraki wonder what it does for systems that don't use swap. may have an even more dramatic effect12:20
wpwrakwolfspraul: so sebastien's screenshots were taken to fbgrab13:24
wolfspraulsaw it13:24
wpwrakyay ! :)13:24
whitequarkis xiangfu very busy now?13:58
wolfspraulok I will do more NanoNote editing (in the news) tomorrow14:16
wolfspraulslowly getting there14:17
rjeffrieswpwrak assuming Nanonote 8:10 SPI --> UBB --> ribbon cable --> [some flavor Arduino]16:14
rjeffrieswhat would one look for so the target Arduino can exchange data with Nanonote "master"16:15
rjeffriesfor now we ignore whether the Arduino can or can not be programmed from this lash up.16:15
kristianpaulrjeffries: i think long time ago that questions you made is answered as posible16:21
kristianpaulbut maybe i lost the point.. :/16:21
rohthere are spi serial converters16:32
rohin the end only a programmed avr, but possible16:32
rohone could programm another ardiuino via that16:32
rjeffriesthanks roh maybe I am unclear myself. I know tuxbrain connected Aeduinno to Ben Nanonote long ago using Ben's serial port17:02
rjeffriesthat would work with any Arduino or clone  model17:02
rjeffrieswhen using SPI to talk to Arduino, I am not sure if ont certain Arduinos can do that, or17:03
rjeffriesmaybe a "shield" with an extra SPI to serial chip is needed?17:03
rjeffrieswhere i am headed is thinking of an Arduino of some ilk connected to Nanonote over17:05
rjeffriesa reasonably high speed connection. then (just a matter of software...;) it would be possible17:05
rjeffriesto connect Nanonote to Ethernet17:06
rjeffriesor interface (via arduino) to I2C periferals17:06
rjeffriesthe major smarts are Linux Ben Nanonote, the Arduino is a semi smart semi independent slave pod17:07
rjeffriesthe Arduino ecosystem offers so many cool and cheap modules but suffers from being quite low level17:08
rjeffriesnew topic: this seems mildly interesting and very open:17:09
whitequarkrjeffries: the problem with ethernet is, you don't have any external interface with sufficiently high speed and host capability17:30
whitequarkmaybe you'll be able to find SDIO ethernet card, but it won't work with SPI17:31
rjeffrieswhitequark well, if goal is connectivity, I think it can work. wpwrak measures (if I recall right...)17:34
rjeffrieswell over a megatbit per second over the 8:10 spi interface.17:34
rjeffriesmost access to internet does not require very high speed.17:35
rjeffriesI am so old i remember using dial modems to connect to internet at various speeds17:35
rjeffriesat 56Kbps, the internet is useable. works great for email or irc and ok for light casual browsing with a text browser17:36
whitequarkrjeffries: there are two points18:06
whitequarkfirst, not everyone uses ethernet for internet. it's sometimes useful to transfer a file to internal media18:06
whitequarkwell, that may be not very useful as there's usb-device and sd-card anyway.18:07
whitequarksecond, pages were loading at acceptable speed then in 56k days. now average homepage may be around a megabyte of rounded corners and transparent PNGs18:07
whitequarkhm, third is that it'd be hard to fit a good browser in ben's 32M18:08
Aylathat's fine using zram swap ;)18:10
kyakwhitequark: is "links -g" a good enough browser for you? It fits well into Ben's 32Mb :)18:15
tuxbrainwhitequark: sure and ethernet module with spi interface will not work? I have been reported with diferent opinions about this18:19
whitequarkkyak: please, try using it for, maybe, a day or two, and you'll answer your question yourself18:29
kyakwhitequark: i don't get your point18:31
whitequarkkyak: it isn't really usable with modern sites18:32
whitequarkat least it wasn't last time I've checked it18:32
kyak"modern sites"? what is it?18:32
whitequarktuxbrain: of course it will work. somehow. looking at PM, SD pins are not multiplexed with SPI, and so you'll need to use bitbang driver in kernel18:33
whitequarkthat isn't very fast and is very cpu-hungry18:33
whitequarkkyak: try opening qi-hardware.com, or maybe google.com, or github.com18:34
kyakwhitequark: http://en.qi-hardware.com/wiki/Applications#links18:34
kyakthis is "opening qi-hardware.com" :)18:34
wpwrakrjeffries: (comm with avr) SPI with the ben the master and the avr the slave should be convenient18:44
wpwrakrjeffries: (from yesterday, SIE with jz4760) not a bad idea. if someone was to redesign the SIE, that would certainly be a better starting point than the aging 472018:48
whitequarkkyak: links cannot be used for day-to-day tasks18:55
whitequarkit is only good to say "hey, our device can load web-pages", but hardly more18:57
kyakit depends on which tasks you do day-to-day18:59
kyaki use elinks regularly to access gmail without any problems18:59
kyakhave to go now19:00
rjeffrieswpwrak how much new Ben software is needed to achieve bi-direcetional data transfer between Ben NN and AVR (read Arduino)19:39
wpwrakrjeffries: just to communicate ? not a lot. you could just reuse my spi code for ben-wpan. the harder bit is the avr side, plus some meaningful protocol that rides on top of spi.19:41
rjeffrieswpwrak ubderstood regards need for a Ben to AVR protocol19:42
rjeffriesif objective is using AVR to handle real time data collection via say I2C or whatever, with AVR/Arduino as a smart beffer or even some data reduction before handoff to ben that could be feasible19:43
rjeffriesbut to get real, why not use a cheap netbook as master and simply communicate to Arduino via USB.19:44
rjeffriesa low end netbook running linux is prolly $200 new oe slightly used19:45
wpwraksure, you can do that. i would try to cut out the man in the middle, i.e., the avr :)19:48
Action: wpwrak hates statistical distributions that don't make sense20:28
tuxbrainwpwrak: what distribution are you talking about?20:32
wpwraktuxbrain: the transmit timing, measured by the ben. i'm trying to determine the atben's clock frequency without direct access to the clock signal.20:37
tuxbrainwpwrak: really, don't use my name followed by black magic power words like frequency , direct access or signal... it really scares me.20:39
wpwraktuxbrain: the method is to load a packet, then initiate transmission with a pulse (there's a dedicated gpio for this). then measure how long it takes until the tx complete interrupt arrives20:40
wpwrakah wait .. lemme check the chip-internal interrupt latency ...20:40
tuxbrainwpwrak: Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn20:41
tuxbrainwpwrak: biboca garagem favela fubanga maloca bocada Maloca bocada fubanga Favela garagem biboca, porra !!! Ze do caixao zumbi lampiao20:44
wpwrakgrmbl. two set of values, an unexplainable 150 us apart20:47
wpwraki understood the first and the second, but you threw me with the catalan ;-)20:48
tuxbrainI think is portugues , is a the Rattamahatta lyrics from sepultura, I don't know what it really means but the song looks like a vudu conjure :P20:51
tuxbrainor maybe a recieipt to do some cake but well , it sounds like vudu cake20:52
tuxbrain150us seems a lot of time on transmision scale, isn't it? (OMG I'm starting to intuit your tech mambo jambo nonsense)20:54
wpwrakthe drugs are starting to work ;-)20:55
tuxbraindrugs+lack of sleep+a lot of qt programing readed is causing me to feel sick....  I think I'm gonna remedy at least one of the three, good night20:57
wpwraktuxbrain: here's some sample data: http://downloads.qi-hardware.com/people/werner/wpan/tmp/tx-100-counts.gz20:57
wpwraktuxbrain: a good way to look at it is, after gunzip'ing, with gnuplot   plot "<sort -n tx-100-counts" with lines21:00
wpwrakto zoom in,  set yrange [30000:33000]  (or zoom manually)21:00
wpwrakyaxis is the number of counts between send trigger and interrupt. one count is about 100 ns21:01
tuxbrainwell no need to see that it seems that it tends to be stable at 31300 aprox but with random jumps of 400 to 1000 units .... whatever it means21:02
wpwrakx axis is the cumulative number of samples. e.g., we have about 7000 samples with ~31300 counts, ~2000 samples between ~31300 and ~32800, and then another ~1000 around 3280021:03
wpwrakthis is a ben with everything that could get in the way dead. including interrupts. actually, let me verify that ...21:04
wpwrakyeah. everything switched off21:05
tuxbrainwell if the input is the same something should be altering the values.... in theory same input sould give you output ... extrange...21:06
wpwrakit gets worse: plot "tx-100-counts" with dots21:06
wpwraknow you can see that there are a lot of samples at the ~31300 baseline. but there's a pattern over time with the ones that don't quite fit. they're also very systematic.21:07
tuxbrainyes I even saw that with the numbers directly.... I think something is happen on the ben on x period21:08
tuxbrainsomething is not off21:08
wpwrakyet i do set ICMSR to 0xffffffff21:09
tuxbrainor the sistem or the CPU is doing something we don't know on that moment cyclic21:10
wpwrakhmm. maybe the frame buffer. switching it off, too ...21:11
tuxbrainI suppose this will complicate the creation of software on the ben side for communications isn't it?21:11
wpwrakin the end, my program will look worse than gmenu2x ;-)21:11
wpwrak(complicate) no, not at all. this is only for production testing.21:12
tuxbrainalso with an advert before the screen shut down... don't move, don't breath, you may alter the values stay froze for a seconds please....21:13
wpwraknaw, the system is only unresponsive for about 3-4 ms21:17
wpwrakof course, 10000 times in a row ;)21:17
tuxbrainwow how long is the test?21:18
wpwrak4 ms * 10k = ~40 s. of course, 10000 is a bit excessive. once things work properly, a lot less should do.21:21
wpwrakyes ! that did the trick ;-)21:24
tuxbrainwas the frambuffer?21:24
wpwrakyup. tuned the lcd clock off and now i get ...21:27
wpwrakthat's with different trim values. t0 is the lowest extra capacitance -> clock runs fastest, t15 the highest -> slowest21:29
wpwrakand this is indeed what we see :-)21:30
wpwrakdistribution looks vaguely gaussian, which is also good21:30
tuxbrainok again im  lost in translation from wpwrakish to tuxbrainian, but if you are happy and you said is good , I'm happy too :)21:40
wpwrak(trim) the load capacitors of the crystal are programmable21:44
wpwrakso changing the trim is an easy test for whether i can accurately measure the clock frequency. the objective is to detect SMT problems. so a whole capacitor would be missing. that would cause a greater divergence than these trim changes.21:46
wpwrakhmm. something in the ben doesn't like it if i turn off the lcd clock. hangs after a while :-(22:06
wpwraktuxbrain: you may get your wish for a "don't touch while testing" mode after all :)22:18
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