Yeaaah, schematics!! One silly question... do you plan to upload the kicad library folders? or where can we get them?
On Mon, Sep 16, 2013 at 11:58 AM, Werner Almesberger <[email protected] > wrote: > Felix wrote: > > Should be possible something like following? > > I was thinking of having such a FET battery switch but since the MCU > already seems to include a similar feature (*), I'd use that. > > The boost converter only gets enabled when using display or memory > card. The transceiver must be powered whenever we need a precise > clock, because it has the system's only crystal. > > Since the transceiver has an efficient built-in off switch and can > run at voltages down to 1.8 V, I'll simply connect it to the same > USB-or-battery supply as the MCU. > > I also placed a fat silo cap (220 uF) on that system voltage rail, to > keep the RTC running when swapping batteries. Will have to see if the > MCU can respond sufficiently quickly and whether "deep standby" current > is low enough for this to work properly. > > The RTC's clock would come from an internal RC oscillator that can be > trimmed by occasionally comparing with the 15 ppm crystal reference. > > I'm not entirely sure whether I interpreted the MCU's power routing > correctly but a few experiments should clarify that :-) By the way, > tentative schematics (still work in progress) and some rough component > placement on the PCB are now in the repository: > > https://gitorious.org/pwsafe/pwsafe/source/hw > > (*) Figure 3-29 on page 93 of [1] and figure 36-2 on page 652. > > [1] > http://cache.freescale.com/files/32bit/doc/ref_manual/KL25P80M48SF0RM.pdf > > - Werner > > _______________________________________________ > Qi Hardware Discussion List > Mail to list (members only): [email protected] > Subscribe or Unsubscribe: > http://lists.en.qi-hardware.com/mailman/listinfo/discussion > -- Felix
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