2012-03-04 00:39 losinggeneration has joined #qi-hardware 2012-03-04 00:41 wolfspraul has joined #qi-hardware 2012-03-04 00:42 chrisb has joined #qi-hardware 2012-03-04 00:43 losinggeneration has joined #qi-hardware 2012-03-04 01:30 HAH! http://javad.com/downloads/javadgnss/publications/20112312.pdf 2012-03-04 01:35 * chrisb takes a look 2012-03-04 01:36 (about GPS et al) 2012-03-04 01:37 another reason why you should ignore tech specs originated in USA, and better do your own technically based specs for anything you want to build 2012-03-04 01:38 if you don't get it what I'm talking about, look at GSM vs the mess they got over in USA with mobile phone bands 2012-03-04 01:39 and they managed to mess it up despite GSM got invented and defined over here in Germany, in a proper decent way 2012-03-04 01:39 now figure where you end with anything invented and specified in USA 2012-03-04 01:40 or simply read that pdf to get an idea 2012-03-04 01:46 DocScrutinizer: my, my let's not generalize. 2012-03-04 01:47 DocScrutinizer: there is a business case as well as a technical case here 2012-03-04 01:47 sure 2012-03-04 01:47 DocScrutinizer: are you familiar with LightSquared and its financial backer? 2012-03-04 01:47 but the business case is always more important than the technical one, when the story starts in USA 2012-03-04 01:48 and no, I never heard of lightsquare before I read that paper some 30min ago 2012-03-04 01:48 but I'm familiar with quite some of the technical headache that got quoted in that paper 2012-03-04 01:48 regarding GPS performance 2012-03-04 01:49 as well as general mindset in industry regarding how to implement sth like a RF rx filter 2012-03-04 01:49 you usually simply copy the reference design 2012-03-04 01:50 not validate the technical fundamentals that it's based on, like sidebands that need to either be included or better cut off by such a filter 2012-03-04 01:51 and I know the quality of reference designs originating in USA vs those e.g. done in Germany 2012-03-04 01:51 and the totally differnet mindset that speaks to me from those schematics 2012-03-04 01:54 losinggeneration has joined #qi-hardware 2012-03-04 02:08 the US has lots of experience with the difference between bands for signalling position and bands for two way communication 2012-03-04 02:09 LightSquared is trying to *innovate* on some unused bandwidth it managed to uncover 2012-03-04 02:09 to create two-way communication bands 2012-03-04 02:11 https://en.wikipedia.org/wiki/Lightsquared 2012-03-04 02:12 they probably have to pump alot of power into a small band, 50MHz, and it bleeds or rings out into well used bands for positioning 2012-03-04 02:13 i hope LightSquared can succeed, but not at the expense of lots of GPS receivers now in service 2012-03-04 02:13 i'm sure very few of these are built in the US 2012-03-04 02:14 it seems to me like a typical issue of innovation in the US 2012-03-04 02:16 it is a similar business case to voice-over-IP and video-over-landline 2012-03-04 02:16 cable TV and telco fight 2012-03-04 02:18 but innovation mostly wins 2012-03-04 02:44 wolfspraul has joined #qi-hardware 2012-03-04 02:46 losinggeneration has joined #qi-hardware 2012-03-04 03:03 Jon Phillips: @robmyers that is great you have a @milkymistvj @qihardware. We need more great owners like you to make it better! Free service for buyers! ( 176140596107427841@rejon - 17s ago via web ) 2012-03-04 03:35 lol, 2012-03-04 03:35 (“I’m not listening! I can’t 2012-03-04 03:35 hear you!”) 2012-03-04 03:37 oh god.. this old school way to work, is a shame.. 2012-03-04 03:39 lol, politicians may be doing more noise that the one that the poor filter desing let pass 2012-03-04 04:12 wej has joined #qi-hardware 2012-03-04 04:15 x201 has joined #qi-hardware 2012-03-04 05:09 Ayla has joined #qi-hardware 2012-03-04 05:46 well, actually I think lightsquared is a bit... squared to consider using Watts-of-TX BTS in a spectrum next to GPS 2012-03-04 05:47 the original culprit of all this mess of course is FCC, what else ;-P 2012-03-04 05:50 for WLAN you have a clear definition of the allowable TX power for each channel, incl crosstalk to adjacent freq. If FCC had considered equally precise specs for GPS band, L^2 never would've thought of such idiotic thing like implementing a terrestrial network some 25MHz next to GPS signals 2012-03-04 05:52 or - depending on that FCC better specs - GPS manufacturers from beginning would've considered using proper filters to get the needed crosstalk resilience into their designs 2012-03-04 05:53 but since, according to FCC general policy, everybody can build crap as long as it simply fails passively and doesn't actively interfere with any other service, the second assumption might as well be incorrect 2012-03-04 06:00 Artyom has joined #qi-hardware 2012-03-04 06:07 DocScrutinizer: BTW Have you heard about very similar situation with GLONASS+GLOBALSTAR like with GPS+lightSquared. 2012-03-04 06:07 nope 2012-03-04 06:08 never heard of globalstar either until now 2012-03-04 06:08 all this brought to my attention by whitequark - thanks for the pointers :-D 2012-03-04 06:16 It works in L-band also. It's frequencies are aproximately from 1610 to 1625 for uplink. (And GLONASS previously used frquencies up to 1609.4 MHz, but now up to 1605,4MHz) 2012-03-04 06:20 And maximum power of user terminal is up to 26 dBm... 2012-03-04 06:36 interesting 2012-03-04 07:19 jekhor has joined #qi-hardware 2012-03-04 07:32 rejon has joined #qi-hardware 2012-03-04 07:40 rejon has joined #qi-hardware 2012-03-04 08:09 rejon has joined #qi-hardware 2012-03-04 08:41 wej has joined #qi-hardware 2012-03-04 08:50 mstevens has joined #qi-hardware 2012-03-04 09:33 kilae has joined #qi-hardware 2012-03-04 09:55 DocScrutinizer has joined #qi-hardware 2012-03-04 11:26 GNUtoo has joined #qi-hardware 2012-03-04 12:21 jekhor has joined #qi-hardware 2012-03-04 12:25 DocScrutinizer: fun fact: here, if someone says "smth is of German quality", then s/he means THE quality 2012-03-04 12:27 like for example there are still some metalworking machines in basements of Moscow State University, which originate from 1940's 2012-03-04 12:27 they still work and are actively used 2012-03-04 12:29 yeah, some time ago we had a record for building that class of stuff 2012-03-04 12:30 even more fun fact: here the almost same term is "Russian tank" 2012-03-04 12:30 rofl 2012-03-04 12:30 it works like a Russian tank 2012-03-04 12:30 or is built like one 2012-03-04 12:31 not very commonly used term though 2012-03-04 12:32 also usually implies you need a hammer to start the unit 2012-03-04 12:32 very true indeed 2012-03-04 12:34 there are a whole lot of Soviet-era tales about different kinds of equipment which won't work unless kicked mercilessly 2012-03-04 12:34 supercomputers, icbms, etc. 2012-03-04 12:39 there's a thing I miss about that, through. each device came with the full printed schematics, even ones as complex as TV's 2012-03-04 12:39 and you could just get your soldering iron and fix it if it has broken 2012-03-04 12:40 there are still chunks of solder sold marked as "for domestic use" 2012-03-04 12:42 (through I don't really get how you could fix a TV with a soldering iron where tip d=8mm and a cylindrical chunk of solder d=12mm) 2012-03-04 12:47 whitequark: that was that way in western europe too. something like 30-40 years ago 2012-03-04 12:48 i have repaired radios from then (with tubes) which even had the schems on the backpanel 2012-03-04 12:52 err radio with electron valves, 40 years old? 2012-03-04 12:52 NAH! ;-) 2012-03-04 12:52 DocScrutinizer: yes. sure 2012-03-04 12:53 but the majority is older. youre right there 2012-03-04 12:53 40 years ago all radios had transistors 2012-03-04 12:53 30 years ago for sure 2012-03-04 12:54 new ones 2012-03-04 12:54 of course there were 40 year old valve radios 40 years ago ;-) 2012-03-04 12:55 but yeah, that schematics inside the device were a nice surprise whenever you opened one of those 2012-03-04 12:56 when you were lucky, they didn't fall apart on unfolding them :-P 2012-03-04 12:57 I think they stopped that habit after several houses burnt down XP 2012-03-04 12:57 then the schematics came with the user manual 2012-03-04 12:58 btw a contemporary fridge of a friend of mine came with a user manual with schematics, marked "for Spain only" 2012-03-04 12:59 maybe there it's still mandatory to ship schematics with some classes of appliances? 2012-03-04 13:00 oh sure, on electric stoves you still frequently see schematics 2012-03-04 13:07 Ayla has joined #qi-hardware 2012-03-04 13:18 DocScrutinizer: burnt down XP? 2012-03-04 13:19 XP == emoticon 2012-03-04 13:20 like :-P ++ 2012-03-04 13:20 maybe better: X-P 2012-03-04 13:21 rather like ;-P * 2 2012-03-04 13:25 * roh must admit he started to like pioneer hifi stuff lately. somehow i can find service manuals online as pdf a lot 2012-03-04 13:32 * wpwrak had a valve radio some 35 years ago. mono. a bit bass-heavy but smooth sound if i recall correctly. i think that was the last critter with such technology in our household. i think the B&W tvs already had transistors 2012-03-04 13:37 DocScrutinizer: (gps) http://www.marcus-spectrum.com/Blog/files/gps-0026-lightsquared-spec.gif 2012-03-04 13:38 err, the accompanying text was in Russian, but approximately this: "a part of L^2's occupied spectrum reaches the L1 band and interferes with M-signal" 2012-03-04 13:39 the M-signal is IIRC the high-precision military code 2012-03-04 13:39 hm 2012-03-04 13:39 making powerful enemies ;-) 2012-03-04 13:53 whitequark: http://www.colorado.edu/geography/gcraft/notes/gps/gps_f.html and thanks :-) 2012-03-04 13:53 http://www.colorado.edu/geography/gcraft/notes/gps/gps.html#SVSignals actually 2012-03-04 13:54 from " 3 GPS Satellite Signals" in menu of first link 2012-03-04 13:54 can't find M-code 2012-03-04 13:55 but yeah, P-code is "precision code" which probably is not used in regular consumer grade devices 2012-03-04 13:56 for your convenience: >>The P-Code (Precise) modulates both the L1 and L2 carrier phases. The P-Code is a very long (seven days) 10 MHz PRN code. In the Anti-Spoofing (AS) mode of operation, the P-Code is encrypted into the Y-Code. The encrypted Y-Code requires a classified AS Module for each receiver channel and is for use only by authorized users with cryptographic keys. The P (Y)-Code is the basis for the PPS.<< 2012-03-04 13:57 PRN == Pseudo Random Noise (iirc) 2012-03-04 13:58 lightsquared, sqaured, well, we need more cools applications around L1 Band 2012-03-04 13:58 s/sqaured/squared 2012-03-04 13:58 kristianpaul meant: "lightsquared, squared, well, we need more cools applications around L1 Band" 2012-03-04 14:00 I'm not totally sure but you should confirm the lenth of that cryptographic bits to be sure is something worth to be classified :-) 2012-03-04 14:00 lenght* 2012-03-04 14:02 sure is 7 days... i mean in the navigation message 2012-03-04 14:08 kilae_ has joined #qi-hardware 2012-03-04 14:22 x201 has joined #qi-hardware 2012-03-04 14:31 rejon has joined #qi-hardware 2012-03-04 14:59 DocScrutinizer: fun problem: assume you want to design a digital probe (for a logic analyzer). it should be high-impedance (>= 1 MOhm), good up to at least 200 MHz, operating at 3.3 V (but larger input range desirable). probe and cable should be as small/thin as possible. also, the thing should be very low-cost. to the point that you can consider it disposable. how would you do it, with industrially available components ? 2012-03-04 15:00 DocScrutinizer: i.e., would you make the probe active ? if yes, how to keep the cable thin ? or passive ? if yes, how to maintain the high impedance ? 2012-03-04 15:01 DocScrutinizer: would you go directly to the LA (maybe 1 m away) or to a bridge board close to the circuit with additional circuit ? 2012-03-04 15:01 (the bridge board could be more complex/expensive. of course, better if it's not needed) 2012-03-04 15:02 as far as "small" is concerned, ideally below 2.5 mm wide/diameter 2012-03-04 15:03 less if possible :) 2012-03-04 15:13 panda|x201 has joined #qi-hardware 2012-03-04 15:13 the simplest would be just a coax, with a FET at its end. then measure the current. but ... how much power does it have to burn ? if i model this as a low-pass RC filter with 10 pF parasitic, it would seem, quite a lot. in the order of 80 Ohm -> 130 mW 2012-03-04 15:14 bridge board, with ~10cm passive wires to DUT 2012-03-04 15:17 and I don't follow your power evaluation, the FET either is closed then n Volt * 0 Ampere, or it's open then 0.0n Volt * ~10mA 2012-03-04 15:17 the main power dissipation only happens during switching 2012-03-04 15:18 which ideally takes no time at all :-) 2012-03-04 15:18 if closed, you'd still need to send a current through it to detect it. and that current would work against parasitic capacitance. 2012-03-04 15:18 that would be a single FET, not a pair 2012-03-04 15:18 ?? 2012-03-04 15:18 i.e., open drain 2012-03-04 15:18 sure, what else 2012-03-04 15:19 the pull-up resistor (on the bridge board) would need to pull the signal up quickly enough 2012-03-04 15:19 yeah sure 2012-03-04 15:19 you usually use current source termination for that 2012-03-04 15:21 I.E. a PNP with a emitter R and basis to a common constant voltage 2012-03-04 15:22 via that common constant vltage you can tune your circuit to give proper rise time with arbitrary parasitic C load (coax cable length) and still not consume more power than needed 2012-03-04 15:22 jekhor has joined #qi-hardware 2012-03-04 15:23 hmm, that would be considerably more than just a FET at the probe, no ? 2012-03-04 15:23 the emitter R typically is very low, like maybe 10 Ohm 2012-03-04 15:23 and more than GND plus signal, too. i.e., you'd have at least also a supply voltage 2012-03-04 15:23 the current source is at your bridge board 2012-03-04 15:24 is there another name for each a circuit ? 2012-03-04 15:24 the probe has just the FET, maybe a gate pulldown R 2012-03-04 15:24 s/each/such/ 2012-03-04 15:24 wpwrak meant: "is there another name for such a circuit ?" 2012-03-04 15:24 or pullup 2012-03-04 15:24 i googled for it and what i found has a current source at the sender and a comparator at the receiver 2012-03-04 15:24 http://books.google.com.ar/books?id=oDWRAxCU-g8C&pg=PA326&lpg=PA326&dq=current+source+termination&source=bl&ots=8_HAAvrfZe&sig=a8vj_bzbc6T7HO17FdcLVujcoxA&hl=en&redir_esc=y#v=onepage&q=current source termination&f=false 2012-03-04 15:25 something like this critter may be nice as a FET. already has gate protection. http://www.vishay.com/docs/66700/si8800ed.pdf 2012-03-04 15:26 may be a bit slow, though 2012-03-04 15:26 damn that google link is useless 2012-03-04 15:26 ;-) 2012-03-04 15:27 1098 cookies I have to deny, then a page with empty/broken pictures 2012-03-04 15:28 but you say just 10 cm wire to the bridge board will be fine ? then we can skip the FET trickery :) 2012-03-04 15:28 http://de.wikipedia.org/wiki/Konstantstromquelle#Mit_Bipolartransistor 2012-03-04 15:29 wpwrak: I dunno if 10cm are fine or not. Largely depends on properties of your DUT I'd guess 2012-03-04 15:30 wpwrak: reverse http://de.wikipedia.org/w/index.php?title=Datei:Konstantstromquelle.PNG&filetimestamp=20110120191559 for PNP 2012-03-04 15:30 so your FET in probe is from collector of that constant-current source (inner of coax) to GND (shield of coax) 2012-03-04 15:32 R1/R2 probably common for all N probe inputs of your bridge board 2012-03-04 15:32 and make it a poti 2012-03-04 15:32 so you can tune the current like I mentioned above 2012-03-04 15:32 ;-) 2012-03-04 15:34 Re is very low, you want the current source be able to deliver some nn mA to a voltage very close to the emitter voltage 2012-03-04 15:34 or you add in a voltage limiter 2012-03-04 15:34 simplest case: a Zener 2012-03-04 15:35 this way you can define the voltage at FET's source and thus the logic level where it will detect a 1 2012-03-04 15:35 hmm, pwm-drive the supply voltage ? 2012-03-04 15:36 of course a simple clamp diode to a constant voltage source common to all probe inputs would be way more versatile and cool 2012-03-04 15:38 the basic benefit regarding current source of such a clampdiode+CV is that your supply voltage for the current source (at Re/emitter) can be several volts higher than the probe high-level voltage, thus guaranteeing that your current source will properly pull up with full current until high level get reached 2012-03-04 15:42 hmm, that would be for M1. we have a 5 V supply. and signals (to the M1) are 3.3 V 2012-03-04 15:42 your parameters for the evaluation then are: 1/(200MHz *(2 + 1for_margin)) rise_time; 10 pico As/V parasitic capacity; 3.3V high level; solve for current needed 2012-03-04 15:43 calculate with 100pF max C_parasit, and evaluate the Re for the resulting needed current @ 5 - 3.3 V 2012-03-04 15:44 then you reduce that current via R1/R2 2012-03-04 15:44 1.6 ns rise time. hmm, what kind of FET has that ? 2012-03-04 15:44 HF FET? 2012-03-04 15:44 Ayla has joined #qi-hardware 2012-03-04 15:45 aah, right. RF FET is the product category :-) 2012-03-04 15:45 kewl, and they go up to 7 A ;-)) 2012-03-04 15:51 rejon has joined #qi-hardware 2012-03-04 15:55 if i have a FET in the probe, is it safe to have a probe cable > 10 cm. e.g., 50-100 cm ? 2012-03-04 16:00 emeb has joined #qi-hardware 2012-03-04 16:00 rejon has joined #qi-hardware 2012-03-04 16:01 wej has joined #qi-hardware 2012-03-04 16:10 Ayla has joined #qi-hardware 2012-03-04 17:00 sure, why not 2012-03-04 17:00 all your probes should have same length though, to eliminate propagation delay diffs 2012-03-04 17:03 yeah, it would be tragic to get that bit wrong :) 2012-03-04 17:03 your signal will move along the coax to the "bridge" at typical cable specific sub-light-speed, and arrive there in the same shape and sequence you fed them into the cable with your FET. Theoretically the cable could be 100s of meters length, and several signal edges traveling along it 2012-03-04 17:05 very good. now, to find a really thin coax cable ... 2012-03-04 17:05 of course you want to terminate the coax with the right R, to avoid reflections 2012-03-04 17:05 since your current source is basically zero impedance, your termination will be series to cable 2012-03-04 17:07 this kinda actually defeats the purpose of the current source somewhat, but meh 2012-03-04 17:08 ;-) 2012-03-04 17:09 i wonder how all those terminations of data lines really work. e.g., to RAM address lines. those inputs don't look like zero impedance to me. 2012-03-04 17:10 assuming your current source is set to deliver less than 50R/3V3 Ampere, it seems still like a good design to me 2012-03-04 17:11 indeed, I'm wondering as well 2012-03-04 17:14 err 3V3/50R of course 2012-03-04 17:18 cool, thanks ! so this doesn't look too hostile. finding a cable may be tricky. digi-key only have thick cables. maybe i should use something like this: http://search.digikey.com/us/en/products/415-0108-250/J10043-ND/1755840 2012-03-04 17:18 only 25 cm, though :-( 2012-03-04 17:19 but i suppose one could source larger ones of the same kind, if determined 2012-03-04 17:19 even thinner: http://search.digikey.com/us/en/products/415-0105-250/J10037-ND/1755834 2012-03-04 17:37 rejon has joined #qi-hardware 2012-03-04 18:01 LunaVorax has joined #qi-hardware 2012-03-04 18:20 oh yeah, now it makes sense when my colleague informed me that the Lauterbach debug connector cable is some 200EUR - it's two 16wire flat cables with coax, about as thin as the one you dug up there. ~10cm length, with two nasty plugs, one each end 2012-03-04 18:22 happyness is .... http://search.digikey.com/us/en/products/U.FL-2LP(V)-04N2-A-(1000)/H11554-ND/1657749 2012-03-04 18:22 ... and a sharp knife ;-) 2012-03-04 18:23 that lauterback cable sounds like the kind they make a total of 100 of. worldwide, throughout human history;-) 2012-03-04 18:23 of course, s/happy/happi/ 2012-03-04 18:29 /doxygen/trunk/Config_ext.html 2012-03-04 18:29 oops 2012-03-04 18:29 http://blog.goo.ne.jp/osqzss/e/af7fe0fe97a2c6b886fdb849efcd6c6f?fm=rss 2012-03-04 18:32 donk ask for details.. as code is no published yet i dont know then.. 2012-03-04 18:33 but is not a milkymist cpu afaik nios II, also guess al windows.. but is a note proof or working namuru in the wild :) 2012-03-04 18:45 LunaVorax has joined #qi-hardware 2012-03-04 18:51 LunaVorax has joined #qi-hardware 2012-03-04 19:29 DocScrutinizer: (heatsinks) hm, doubtful 2012-03-04 19:29 I called the module, answered the call on it and hold it for a minute or two 2012-03-04 19:29 it's hardly warm 2012-03-04 19:31 *held it. not in the telco sense, just left my phone lying with the call going on 2012-03-04 19:35 whitequark: you can't really control the OTA situation, so you have no clue how much of its theoretical 100% power the TX actually had to use for your 1min call 2012-03-04 19:35 if you didn't talk, odds are it didn't send much at all (silence TX cancellation) 2012-03-04 19:36 when you're close to the BTS, odds are your TX worked with power correction factor like *0.0001 or sth 2012-03-04 19:37 there'S basically no decent way to test those things, that's why a decent datasheet mentions the heat sink requirements of such a component. They have means to test worst case at that fab where those modules got developed 2012-03-04 19:39 silence TX cancellation probably aka pasue compression or sth like that 2012-03-04 19:39 pause* 2012-03-04 19:39 basically means that TX doesn't wase power to TX data that's just transporting silence 2012-03-04 19:39 waste* 2012-03-04 19:44 well, this datasheet is indeed not "decent" 2012-03-04 19:44 and I indeed did not talk 2012-03-04 19:44 hm 2012-03-04 19:45 would a microwave oven work? 2012-03-04 19:45 that is, I put the module in the (turned off) oven which is basically a faraday cage 2012-03-04 19:45 and then open it a bit 2012-03-04 19:45 oh 2012-03-04 19:45 microwave 2012-03-04 19:45 viric: wat? 2012-03-04 19:45 I was waiting for the time when microwave ovens appear at #qi-hardware 2012-03-04 19:45 ;) 2012-03-04 19:45 what's so special about them? 2012-03-04 19:45 they can kill 2012-03-04 19:46 indeed 2012-03-04 19:46 almost anything can kill, if used properly 2012-03-04 19:46 nicer, if killing with open hardware 2012-03-04 19:47 well, you indeed need to keep it open to kill anyone... 2012-03-04 19:47 :) 2012-03-04 19:47 sorry for the pause in your conversation. go on go on 2012-03-04 19:48 nah, I said whatever I wanted 2012-03-04 19:48 Isn't there any kernel patch that can make the kernel remember the backlog buffer of every virtual console, regardless of switching' 2012-03-04 19:48 ? 2012-03-04 19:48 is this so high tech? 2012-03-04 19:48 oh, just go to lkml and troll them a bit 2012-03-04 19:48 faster than just asking 2012-03-04 19:48 hm could work 2012-03-04 19:49 I've a 80x25 console, switched the vc, and I lost my valuable 8KiB of backlog... what is this trying to optimise?! 2012-03-04 19:49 memory consumption? 2012-03-04 19:50 that is 2012-03-04 19:50 on a 7MB kernel? 2012-03-04 19:50 the consumption of users' memory by this behavior 2012-03-04 19:50 haha 2012-03-04 19:50 modprobe pcspkr takes more memory 2012-03-04 19:51 sigh. DCD is "circuit 109", and DTR is "circuit 108/2" 2012-03-04 19:51 crazy telcos 2012-03-04 19:51 where's circuits 0..99 ? 2012-03-04 19:51 100 is a good start for a three digit number 2012-03-04 19:52 why not 000 ? 2012-03-04 19:52 that may mean writing %03i instead of %i 2012-03-04 19:52 I could argue that DCD and DTR were invented before printf 2012-03-04 19:53 yea, RS232 is of 1969 2012-03-04 19:53 history is full of coincidences 2012-03-04 19:53 whitequark: yes, a good idea, just don't open it. You won't believe it but microwave ovens are all but tightly sealed for 900/1800MHz 2012-03-04 19:54 DocScrutinizer: the magic space frequency of the grid of holes of the front door 2012-03-04 19:54 DocScrutinizer: er. did I understand you correctly? microwave oven kills 2.4g but allows 900m/1800m to pass? 2012-03-04 19:54 yes 2012-03-04 19:54 huh 2012-03-04 19:54 lamda/2 seals 2012-03-04 19:55 but won't lambda/2 seal it for lambda*2 ? 2012-03-04 19:55 maybe they're caled lamda/4 seals, dunno. but yes, they should also work for subharmonics 2012-03-04 19:56 so 2400/2, */4, etc 2012-03-04 19:56 hm, I meant a bit different thing. if my math is any good, then λ(2.4g)=.125m, and λ(1.8g)=.166m 2012-03-04 19:57 whatever 2012-03-04 19:57 why would holes made to seal .125m pass .166m? 2012-03-04 19:57 not holes 2012-03-04 19:57 the cage size 2012-03-04 19:57 resonating gap between door and case 2012-03-04 19:58 oh. so it isn't sealed tightly? 2012-03-04 19:58 not at all 2012-03-04 19:58 ... weird. I'd rather not stand near microwaves anymore 2012-03-04 19:58 hehehe 2012-03-04 19:58 well, at least it explains why 900m/1.8g escapes 2012-03-04 19:59 yup 2012-03-04 19:59 hm, but why gap and not a close connection? 2012-03-04 19:59 then place some electric toothbrush or whatever into the oven as well, to make some noise the phone can transmit 2012-03-04 20:00 very first microwave had seals. They were extremely expensive, unconvenient, and easily broke by a simple 0.5mm of random dirt between the elastic metal fibre and the case frame 2012-03-04 20:03 hm, so the sealed approach requires seal to be maintained at all times or the radiation would escape 2012-03-04 20:04 and the gapped one allows for any shit to accumulate in the gap as long as it's precisely the required size 2012-03-04 20:04 cool 2012-03-04 20:07 can you also explain this... if I'd put a %metal_thing% to an oven and turn it on, I'd get a nice discharge and a small lake of molten metal 2012-03-04 20:07 but if I put a %metal_cup_for_microwave% into it, I won't see any of the effects. it won't get even slightly hot 2012-03-04 20:07 why? 2012-03-04 20:08 I never really understood this 2012-03-04 20:09 there is a 'metal cup for microwave'? 2012-03-04 20:11 wej has joined #qi-hardware 2012-03-04 20:11 yeah 2012-03-04 20:11 I've never seen one 2012-03-04 20:13 google for "microwave compatible metal [cup]" 2012-03-04 20:14 DocScrutinizer: huh, _very_ interesting 2012-03-04 20:14 you can run arbitrary code on the CPU of this module 2012-03-04 20:15 well, "SIMCom Core Software and Embedded Application manage their own RAM areas. Access from 2012-03-04 20:15 one of these programs to another’s RAM area is prohibited and will cause fatal error. 2012-03-04 20:15 but it's still interesting. I bet they have quite a few holes there 2012-03-04 20:15 you can also easily downgrade firmware, nothing prevents you from doing that 2012-03-04 20:16 whitequark: depending on architecture, you hardly will find any hole 2012-03-04 20:16 ARM926EJS 2012-03-04 20:16 afaik it's embedded in an ASIC 2012-03-04 20:17 on STE modules we have PSEL and PSEL_SECURE to access peripherals in secure and unsecure mode. Same for RAM access 2012-03-04 20:18 "The ebdat4_04Wdtkick function kicks the watch dog." 2012-03-04 20:18 poor animal :/ 2012-03-04 20:18 we got 3 ARM cores, one for network stack (aka GSM/LTE/*), one for communications between all the subsystems on SoC, and one App core 2012-03-04 20:18 in this case, looks like everything is running on the single core 2012-03-04 20:19 well, at least that's what I think after looking at a vast amount of docs 2012-03-04 20:19 and even the 4words deep FIFO 5 chan "mailbox" function block has 3 nonsecure and 2 secure channels 2012-03-04 20:20 our customers never get to know about NS and COM core or the functions/processes running there 2012-03-04 20:20 err, I bet the "display interface" present in this module is made for Nokia 3310 display or equivalent one 2012-03-04 20:21 ah baseband.... 2012-03-04 20:21 what about that: 2012-03-04 20:21 they might think the whole M7400 modem SoC has just one ARM core to run some general purpose things like AT interpreter and their custom 'apps' 2012-03-04 20:21 http://www.pastie.org/private/ana4aetc6o9qzt4w7wtma 2012-03-04 20:22 seriously, it even has some embedded melodies for games 2012-03-04 20:22 pastie.org? no way 2012-03-04 20:22 DocScrutinizer: what's wrong with pastie? 2012-03-04 20:22 can run on compal_e99 (c155 ) or gta02 or another phone 2012-03-04 20:22 too much crap 2012-03-04 20:22 ah sorry I forgott 2012-03-04 20:23 http://paste.debian.net/158551/ 2012-03-04 20:23 ooh actually it kinda works, at least better than pastebin.com 2012-03-04 20:24 I should implement poweroff I think 2012-03-04 20:24 GNUtoo: what's that? 2012-03-04 20:24 nuttx on the calypso 2012-03-04 20:25 hmm 2012-03-04 20:25 so that you can have an unix-like OS abstraction 2012-03-04 20:26 so you could easily move the upper layer(layer23) on the modem 2012-03-04 20:26 because currently layer23 runs on a GNU/Linux computer 2012-03-04 20:26 reminds me of how they embedded busybox in grub2 2012-03-04 20:26 so in case of gta02 that prevent the CPU from sleeping 2012-03-04 20:27 in the case of a feature phone it's even worse 2012-03-04 20:27 grub2 becoming a wanna-be-OS like uBoot now? 2012-03-04 20:27 you have to connect it to a computer to use it 2012-03-04 20:29 DocScrutinizer: exactly 2012-03-04 20:30 but it's kinda more advanced. for example, it has a working almost-POSIX shell 2012-03-04 20:30 nuttx, cool :-) 2012-03-04 20:30 still very wrong IMO 2012-03-04 20:30 they could as well compile Linux, bootstrap it from stage2 and then kexec to the desired kernel 2012-03-04 20:31 yup 2012-03-04 20:31 wej has joined #qi-hardware 2012-03-04 20:31 * kristianpaul agree too 2012-03-04 20:32 GNUtoo: DocScrutinizer: maybe you possibly know any AT-command parser libraries? 2012-03-04 20:32 that is, which could run on a uC with 8k ram 2012-03-04 20:32 ergh, what you want AT? 2012-03-04 20:32 whitequark, you're involved in basebands too? 2012-03-04 20:32 nope, sorry 2012-03-04 20:32 send commands while obeying flow control, decode & encode SMS, parse unsolicited return codes 2012-03-04 20:33 GNUtoo: nope, just a side project which I make for a practical purpose. I use some GSM modules in it and need to interface them 2012-03-04 20:33 ok 2012-03-04 20:33 ah I get it: 2012-03-04 20:33 <-----> 2012-03-04 20:33 yup 2012-03-04 20:34 imagine that you could do <-----> peripheral 2012-03-04 20:34 that would be so cool 2012-03-04 20:34 it would save ton of power 2012-03-04 20:34 etc... 2012-03-04 20:34 but for that we need to move layer23 in the microcontroller 2012-03-04 20:34 GNUtoo: I can, actually 2012-03-04 20:34 s/microcontroler/ in the calypso/ 2012-03-04 20:34 they have SDK for that 2012-03-04 20:35 ok 2012-03-04 20:35 but fuck it, I don't want to have anything running on that chip 2012-03-04 20:35 er, just look at docs 2012-03-04 20:35 "Reset the module frequently is not recommended and it may cause some unexpected fault. 2012-03-04 20:35 what's the module model+company? 2012-03-04 20:35 SIMcom SIM900D 2012-03-04 20:35 ok 2012-03-04 20:35 it has some interesting features 2012-03-04 20:35 like AT+SIMEI 2012-03-04 20:35 guess what does it do 2012-03-04 20:36 sim I/O ? 2012-03-04 20:36 let me look in the AT manual 2012-03-04 20:36 not quite. and it's udoc'd 2012-03-04 20:36 AT+SIMEI="". 2012-03-04 20:36 ok 2012-03-04 20:36 lol 2012-03-04 20:37 it "restricts" you by "limiting" the count of imei changes by 2 2012-03-04 20:37 lol 2012-03-04 20:37 but actually, you can "reflash" it by sending 50 proper bytes to a debug port 2012-03-04 20:37 ok 2012-03-04 20:37 which kinda allows you to change IMEI on what frequency you want 2012-03-04 20:37 each minute 2012-03-04 20:37 whatever 2012-03-04 20:37 ok 2012-03-04 20:37 how did they get it certified?! 2012-03-04 20:37 good question 2012-03-04 20:38 well, it's probably not part of the cert at all 2012-03-04 20:39 so there's no such point in certification like "make sure the ME could not change its IMEI at the will of user"? 2012-03-04 20:39 basically cert first of all checks OTA compliance 2012-03-04 20:39 whitequark: I don't think there's such a point 2012-03-04 20:39 OTA = um ? 2012-03-04 20:39 over the air 2012-03-04 20:39 yes so it's um 2012-03-04 20:40 "It is suggested that it’s better to do some ESD protection in user’s application to improve the ESD 2012-03-04 20:40 character of the module, especially for the signal connecting to external interface, for example, 2012-03-04 20:40 I like how they write the datasheets 2012-03-04 20:43 DocScrutinizer: huh, I found a (deep buried) appnote which describes how to convert mic-in to line-in 2012-03-04 20:43 i.e. what I want 2012-03-04 20:43 it's basically the same thing you have described 2012-03-04 20:46 hm 2012-03-04 20:46 there's an appnote about how to activate jamming detection 2012-03-04 20:47 is it a common function across GSM modules?.. 2012-03-04 21:04 nope 2012-03-04 21:20 LunaVorax has joined #qi-hardware 2012-03-04 21:24 antgreen has joined #qi-hardware 2012-03-04 21:25 DocScrutinizer: oh wow. "6.2.24 AT+CENG Switch On or Off Engineering Mode 2012-03-04 21:26 http://paste.debian.net/158558/ 2012-03-04 21:26 wej has joined #qi-hardware 2012-03-04 21:31