[Arm-netbook] KiCAD based A10 break out / prototyping PCB finished
luke.leighton at gmail.com
Wed Feb 6 17:40:36 GMT 2013
On Wed, Feb 6, 2013 at 9:41 AM, jm <joem at martindale-electric.co.uk> wrote:
> The power chip as far as I know is not 100% essential, because again as
> far as I know, it then requires the software to be working to control
> it. (Anyone who knows better can correct me on this.)
it doesn't. by default it's set up to not require any programming
(external pull-ups), enough to at least get you bootstrapped (boot
stage 1). in there you can set up the DRAM power etc. etc. and that
gets you to stage 2.
if you *don't* have an AXP209 (like wits-tech and the cubie team have
done), and you try to do something like the MK802 does, which is to
just use some SOT23-5 (SY8008B) DC-DC converters, then you end up with
no proper power regulation and *massive* overheating.
btw i've been reading freescale's application notes on power
management: they go one level beyond even what the AXP209 does, which
is to use different DDR3 voltages, DDR3 clock rates and
GPIO-switchable ODT termination resistor banks.
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