#qi-hardware IRC log for Friday, 2014-01-17

nicksydneyinteresting comment from some Imagination 'Technology PR' regarding open source drivers for PowerVR http://www.cnx-software.com/2014/01/10/a80-optimusboard-features-allwinner-octa-core-big-little-soc/#comment-14766000:05
nicksydneywpwrak: was looking at y-box schematics http://downloads.qi-hardware.com/people/werner/anelok/tmp/ybox-draft-20140116.pdf .. can you tell me please why the CON2 GND is connected to VBUS from CON3 and VBUS from CON2 connected to GND of CON3 .... I thought it should be GND - GND and VBUS to VBUS ? sorry bit lost here :)00:20
rohd- and d+ get swapped too00:27
rohthe connector is pinned reverse or so00:27
wpwrakseems that some idiot forgot to flip the thing00:28
rohnice find nick00:28
nicksydneywpwrak: *whew* sorry I thought there is a reason behind the switching of those 2 as I'm still new in this kind of things so was not sure whether it's my understanding :)00:29
nicksydneyroh: thanks00:29
rohthats what review is all about! :)00:29
rohsomebody learns something, and somebody doesnt fry his usb device ;)00:30
wpwrakactually .. lemme check whether the schematics symbol is correct ...00:30
nicksydneywpwrak: you are using this USB connector  http://www.digikey.com/product-detail/en/ZX62-B-5PA%2811%29/H11634CT-ND/1993369 and I have this kind of connector   http://www.ebay.com/itm/320986999116 that it looks the same in terms of pin connection am i correct ? .... and also when i was playing with my USB LED board I solder the 4 legs not to GND but yours is connected to GND...what is the benefits of connecting the 4 00:33
nicksydneyleg to GND ?00:33
wpwrakthe shield shouldn't float. not sure if just connecting all the shields is ideal but it can't be entirely wrong either00:38
wpwraksymbol looks right. so the routing is indeed wrong00:38
wpwraknicksydney: thanks a lot ! that saved me some future headache :)00:38
wpwrakwill fix it later. gotta run now.00:39
nicksydneywpwrak: no worries....thanks for sharing the schematics it helped me also to learn a number of things of connecting USBs together :)00:39
nicksydneywpwrak: for CC2543 how do you begin in determining what components to connect to which pin when you start designing this ? do you go through and read everything that is in the datasheet ? or there is something like a reference template that is provided by the chip vendor00:42
nicksydneyI was thinking if we want to start designing something with a new chip reading through datasheet for someone like me is going to be a nightmare as surely I won't be able to understand all the detail technical specs that is listed inside the datasheet so interested to know what are the normal steps that you take00:43
nicksydneywpwrak: was googling for 2450BM15A0002 and found this http://www.ti.com/lit/an/swra297b/swra297b.pdf ... noticed on page 4 there is a diagram http://ctrlv.in/284141 .... was wondering if the function of L252 shown is the same as the Y-box  R2 ?00:52
nicksydneyit's so cool..that the discrete components that TI normally used now sits nicely and pretty in 1 single 'small' chip http://ctrlv.in/28414400:53
nicksydneywpwrak: another question...looking through CC2543 datasheet pg 21 under the 'Application Information' section pin 18 is connect to GND while y-box is to 3v3 ... and pin 23 and 24 connect to 3v3 with 220pF and 100nF while datasheet  connect pin 23,24 and 29 straight to power (2-3.6v) ?01:07
nicksydneysorry too many questions :)01:07
nicksydneyboy oh boy..CC2543 is not cheap eh...digikey selling them for over $6/piece :(01:09
nicksydneywpwrak's battery holder porn http://downloads.qi-hardware.com/people/werner/anelok/tmp/bat-holders.jpg  :)01:20
nicksydneyinteresting concept http://www.indiegogo.com/projects/cloudphone-3g-revolutionize-how-you-care 03:09
nicksydneyinteresting to make this as open source project :)03:09
nicksydneyDocScrutinizer05: seems like Neo900 can be used for this kind of thing --> http://www.indiegogo.com/projects/cloudphone-3g-revolutionize-how-you-care 03:18
nicksydneyDocScrutinizer05: just removed all the unnecessary parts that we don't need :)03:18
nicksydneyDocScrutinizer05: Neo900 has got Barometer/thermometer ... is the thermometer can be use to measure body temperature too ?03:19
wpwraknicksydney: (selecting cc2543 pins) well, first i have a look at what functions are in the chip. then i select the ones i need. e.g., UART in SPI mode for SPI and a timer output for the clock that goes to the KL2503:42
wpwrakthen there are often various pins one can select for one function. so i try to pick something that looks low on conflicts and where the order of signals on both ends matches03:43
wpwrakthis is just heuristics. sometimes i find that my choice wasn't all that great and i reassign them later on03:43
nicksydneywhat you mean by "looks low on conflicts and where the order of signals on both ends matches" ?03:43
wpwrak"low on conflicts" = not in an area where lots of things come together (if i have a choice)03:44
wpwrak"order of signals" = if chip 1 needs to talk to chip 2 and chip 1 has the signals A B C D in this fixed order but i can configure different orders for chip 2, then i should try to find something close to A B C D as well03:45
wpwrakelse i have a lot of crossed signals03:45
nicksydneythe signals A B C D you are referring to is SPI et al ?03:46
wpwrak(L252) yes, that's the matching/tuning circuit. their LC combination is a bit unusual. but i guess they know what they do :)03:47
wpwrakthe values in the tuning/matching circuit depend on lots of hard to calculate factors. sometimes you don't need anything. so it's all trial and error. for the prototype, i don't plan on making a lot of RF optimization experiments. but i include space for the components in the circuit, so that it can be tuned if needed.03:49
wpwrak(pin 18) that looks like a bug in TI's schematics ;-)03:51
wpwrak(other pins) note the fine print in the data sheet: "Power Supply Decoupling Capacitors are Not Shown"03:52
nicksydney(pin 18)..how do you deduce it's a bug ? is it because the pin is labelled VDD so it should not be to GND ?03:53
wpwrakin anelok/anelok, run  dsv ccsch03:54
wpwrakthat's their reference circuit. that's the one i used as a basis for power. and it has pin 18 ad VDD,03:54
wpwraklike the data sheet does almost everywhere. but yes, it's a not very nice bug in ti's documentation.03:55
wpwrak(signals A B C D) yes. SPI has lots of them, and the order often has slight variations03:56
nicksydney(dsv) no data sheet found for "ccsch" ?03:59
nicksydneywpwrak: another balun for CC254x http://www.st.com/web/catalog/sense_power/FM139/CL1806/SC1508/PF258444?ecmp=pf258444_enews_stnews_jan2014 :)04:10
wpwrakgit pull; make dsv; dsv ccsch04:15
wpwrak"Coated Flip-Chip on glas" argh ;-)04:16
nicksydneyno idea whatever that do to the chip :)04:18
rjeffrieswpwrak cool small e-ink displays: http://www.the-digital-reader.com/2014/01/16/atmel-pervasive-displays-launch-new-diy-kit-w-e-ink-screens/05:31
nicksydneyrjeffries: http://www.seeedstudio.com/depot/204-eink-display-shield-p-1374.html06:17
nicksydneyvery nice for debugging http://www.chipquik.com/store/probes.htm 07:24
wpwraknicksydney: (flip-chip) means it's damnably small ;-)08:48
wpwraknicksydney: cut ... but the prices are evil08:50
wpwrak#s/cut/cute/ # that was typed at resting caffeine levels ...10:37
nicksydneyyeah the price is evil !10:51
nicksydneybut nevertheless the idea is really interesting..wish someone will make it more cheaper say like $10 / piece10:51
wpwraki guess there ought to be something on aliexpress ... ;-)10:55
nicksydneywpwrak: nah nothing there has looked around :)11:34
DocScrutinizer05nicksydney: no11:46
DocScrutinizer05it probably is even useless to probe ambient temperature11:47
nicksydneyDocScrutinizer05: was thinking if we strip off all the unneeded features of Neo900 it can be used something like the cloudphone project...probably add some other stuff like heart-rate sensors, temp sensor :)11:48
nicksydneyoh well it was just a thought :)11:48
DocScrutinizer05I don't like clouds11:49
wpwraklet's not forget penis size. this information is essential for targeted marketing :)11:53
nicksydneywpwrak: found a site with lots of kicad library and footprint http://smisioto.no-ip.org/elettronica/kicad/kicad-en.htm 13:02
wpwrakah, nice, with 3D drawings. i never have the patience for these.13:36
wpwraknicksydney: that STM balun is growing on me. it seems to have very nice characteristics ...14:37
wpwrakdigi-key are getting sloppy, though: Description: "BALUN IPD 500OHM FLIPCHIP". Yeah, as if ;-)14:40
rjeffriesnicksydney a more recent page at Seed: https://www.seeedstudio.com/depot/204-eink-display-shield-p-1374.html (price decrease of 50 pct)15:17
paul_boddierjeffries: Product discontinued. You want http://www.seeedstudio.com/depot/small-epaper-shield-p-1597.html?cPath=34_82 which looks like a remake of the Adafruit board.16:31
paul_boddieSee also: http://en.qi-hardware.com/wiki/Ben_E-paper16:33
wpwraki hope the screens are powered by some diesel generators :)20:46
Action: DocScrutinizer05 reads >>...supports more than 170 langusges<< and thinks http://de.wikipedia.org/wiki/Karibik-Languste21:21
qi-bot[commit] Werner Almesberger: modules/pads.fpd: add -NOSILK variants; add silk measurements for rectangular pads (master) http://qi-hw.com/p/kicad-libs/76039af23:25
wpwrakand we have http://downloads.qi-hardware.com/people/werner/anelok/tmp/ybox-draft-20140118.* versions23:47
wpwrakmade the ground on the RF side a bit nicer, moved the TPs around some more, and added a TP on VBUS, for production testing23:48
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