#qi-hardware IRC log for Thursday, 2012-05-10

Textmodewhitequark: plural of cluebat, a bludgeoning weapon who's blows supposedly imbue the target with a clue...similar in concept to a clue-by-four02:11
mthrelated topics: lart02:30
Textmodemth: :302:51
wpwrakphew. server/firewall resurrected. after 3 hours of fighting :-(04:58
qi-botThe build was successful: http://fidelio.qi-hardware.com/~xiangfu/build-nanonote/openwrt-xburst.full_system-20120509-0421 10:08
whitequarkI discovered an interesting thingy16:04
whitequarkUSB Charging Specification16:04
whitequarkand there's something called ACA16:05
whitequarkaccessory charging adapter16:05
whitequarkbasically if you have an otg host and want to power a peripheral and charge the host simultaneously, there's an ID pin value for that16:05
whitequark(full ACA requires two FETs, four resistors and a small uC, but that's only required to handle two connected OTG devices)16:06
whitequarkso I just hardwired everything for a case of OTG Host -- Regular Peripheral16:06
whitequarkI wonder why no one ever manufactures ACAs16:06
whitequarkseriously, it's an incredibly valuable thing to have--for example, an OTG host alone most certainly cannot power a hard disk16:07
whitequarkor an external CDMA modem (I tried)16:07
whitequarkand there's not even a single page on some site last updated in 2008 widh design from 199816:08
wpwraksounds like a standard that has only been implemented on one platform:16:09
wpwrakon powerpoint :)16:09
whitequarkI have yet to patch PMIC driver in my OTG host, through. it doesn't support this mode out of the box16:09
whitequarkpresumably because there's no adapters at all16:10
whitequarkbut it's really cool and useful16:10
wpwrakperhaps it would be :)16:10
whitequarkwhen I understood what I want, I was quite sure there's a standard for it16:10
whitequarknow I just hope that FET layout in that PMIC will allow me to configure it to not short-circuit OTG charge pump to external charger16:11
whitequarklike it tries to do now16:11
whitequarksurprisingly, OTG pump wins16:11
whitequarkand external charger painfully squeaks16:12
wpwrakthere's a "standard" for almost everything :)16:12
whitequark(it was an accident. some moron made an USB cable with ground being without insulation and ID pin in a black insulation. of course I fucking mixed up these wires.)16:12
whitequarkI regularly meet with USB cables manufactured by morons16:13
whitequarkprevious one had D+ and D- switched16:13
whitequarkthat is, D+ was white and D- was green16:13
whitequarktook me a day of debugging to determine why my device won't enumerate. yuck.16:13
whitequarknow I want to kill.16:14
wpwrakas long D+/D- are matched end-to-end .. :)16:15
whitequarkthey were in the cable.16:15
whitequarkbut I cut it in halves and connected the end with A plug to my device.16:16
whitequarkI somewhat expect that once I'll encounter a cable where ground will be red and vbus will be, I dunno, green16:16
wpwrakblack ? :)16:17
whitequarkand then something expensive will explode miraculously16:17
whitequarkit's funnier with green16:17
wpwrakthat's what you get for tampering with carefully engineered equipment16:17
whitequarkclamp diodes explode better16:17
whitequark"carefully engineered equipment" oh, you reminded me of a phrase I once seen in a manual16:18
wpwrakrule #67345: never trust a cable's colors at face value. always measure :)16:18
whitequark>Your device is a product of superior design and craftsmanship and should be treated with care.16:18
wpwraktranslation: "keep your dirty fingers away"16:18
whitequarkI especially like the part about "superior design"16:18
whitequarkmakes me think of nazis or something like that.16:19
whitequarklooks like nokia first made the phrase and then everyone else copied it16:19
whitequarkI seen it in docs for some EXCEPTIONALLY CRAPPY wireless modules16:19
whitequarkand by "exceptionally" I mean that they can compete with PICs in crappiness16:20
whitequarki.e. adding them to your device will yield a net negative result.16:20
LunaVoraxHello everyone!20:34
whitequarkI never thought one could screw up in so many places in a simple USB connector21:02
whitequark1) wrong colors21:02
whitequark2) wire too thin for a hard drive to spin up21:02
whitequark3) loose contacts21:02
whitequark4) what else?..21:02
viricunconnected shield21:07
GNUtoo-desktopwhitequark, I'll try to order a new usb connector for my nexus S( serial cable broke some time ago) from sparkfun(so it's rock solid, breakout board)21:12
GNUtoo-desktopI'll do it tomorrow21:12
GNUtoo-desktopthe previous one broke....21:12
viricis sparkfun related to the unconnected shield?21:26
whitequarkviric: unconnected shield is required by spec on the peripheral side21:30
whitequarkto avoid parasitic currents via groundloop21:30
whitequarkthat is, on host side it is connected and on peripheral side it isn't.21:30
viricah nice21:32
DocScrutinizerhaha, that's fun, for OTG23:08
--- Fri May 11 201200:00

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