#qi-hardware IRC log for Wednesday, 2015-03-25

arossdotmelooks like it's ok to use li-ion charges with li-po00:26
arossdotmeso whats the darn vottage to let to dischage to before the cut off point?00:26
arossdotmelet it discharge too00:26
arossdotmeit's hard to find itfo00:27
arossdotmelooks like lowbat is 3.2v according to adafruit's low batt led on there products01:48
DocScrutinizer05arossdotme: I'd rather use 3500mV aka 3.5V04:31
DocScrutinizer05LiIon (incl LiPo) chemistry suffers *massively* from deep discharge04:31
DocScrutinizer053.00V is the ABS MAX deep discharge where you're supposed to dicard the cell safely when ever crossing that line04:32
DocScrutinizer05anyway >>90% of the available capacity of a LiIon standard chemistry cell are in a discharge voltage range between 4200mV and down to 3550mV04:35
DocScrutinizer05I'd not charge the cell to >4100mV either04:35
DocScrutinizer05those designs that use 4200mV-3200mV or even lower, are made for maximum effect in time of sale, not bothering at all about expected livespan of product / battery. A careully gently managed battery can live >7 years, while those "max perfomance" designs calculate with a battery livespam of < 2 years04:38
DocScrutinizer05oftem < 1 year04:39
arossdotmeDocScrutinizer thx  iw ould like max batt life span,12:13
arossdotmethe chrager is setup to charge upto 4.19v if i'm not missing out the 3rd digect12:14
DocScrutinizer05then use 3.55 .. 4.1V (dis)charge cycle limits12:14
arossdotmewhich i realise now the 3rd digect makes a diff when talking about it12:14
arossdotmethe min vottage in the sys power info is something like 4.7something12:15
DocScrutinizer054.15 is maybe still ok, 4.2 is pushing it quite a bit12:15
DocScrutinizer054.7 doesn't make sense12:16
arossdotmei'mm ignore that vaule then12:16
DocScrutinizer054.7 sounds like min USB VBUS voltage12:16
arossdotmemy bad12:18
arossdotmeits 3475000v12:19
arossdotmeit's hardware charged12:22
arossdotmei'm just refering to the sys files the batt monitors use12:22
arossdotmebut i now have a better idea of what votage to dischage too before rechage12:23
DocScrutinizer053475000┬ÁV sounds like a reasonable End of Discharge Voltage15:27
arossdotmeEDV so thats what its called16:35
eintopfin german: electronische datenverarbeitung16:50
eintopfqi-bot: thanks16:51
eintopfhttp://www.libreboot.org/docs/install/images/x200/x200_pomona.jpg - what's the name of such blue connector?16:59
eintopfoh, I need such connector17:00
eintopfPomona 525017:12
eintopfthat's the name17:12
eintopfvery expensive17:15
kristianpaulwpwrak: had you looked the msp432?17:56
wpwrakkristianpaul: not really. yet another vendor-specific architecture, much like avr. why build on this if we can have nice arm-based MCUs, from so many different sources ?18:06
kristianpaulwell, just thinking on the power comsuption could be not as low as the msp430 but interesting18:07
kristianpaulto be honest the only 32 bits mcu i can get here is fro microchip :D18:08
eintopfI worked with the msp43018:19
eintopfand it was a mess with the toolchain18:19
eintopfbut I heard that ti did some project with redhat to support msp430 to "mainline" gcc18:20
eintopfbefore it was a mess18:20
zeirisI think msp432 is just an Cortex M4 with TI's modules. That doesn't sound so bad.18:20
zeirisThe FRAM MSP430s are very cool.18:21
eintopfhttp://www.ti.com/tool/msp430-gcc-opensource - looks better18:21
eintopfand I had a hardware bug and I couldn't start the bsl via bitbanging18:22
eintopfI implement a small bootloader which starts the bsl when user button is pressed application start :D18:22
eintopfs/pressed/pressed after/18:23
wpwrakzeiris: oh. msp432 is not just another msp430. i see.18:30
wpwrak"The Device Descriptor Information (TLV) section contains a 128-bit true random seed " ;-) http://dilbert.com/strip/2001-10-2518:32
larscprobably even the same on each device18:39
wpwrakthe idea is good, but they really should have use different words to describe it18:39
wpwraklarsc: no, apparently each device gets its own18:39
wpwraksimilar to the unique numbers other manufacturers use18:40
zeirisWould trusting the silicon vendor to discard the random seed immediately after generation+burn be reasonable given that you must trust them to not insert backdoors into the silicon? :)18:50
larsceven if they'd store it, would still be pretty hard to match it to the hardware19:27
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