An RTOS should be able to enumerate both buses and start streaming
within half a second.

A non-RTOS can be used to prove the hardware works before writing the
RTOS tasks.

On Sun, Mar 11, 2018 at 11:42:22PM -0400, Neil wrote:
> I mentioned a bit earlier today that I'm avoiding OS'es due to boot time=
=20
> or even wake time... it will be battery powered.  The camera needs to=20
> start recording ASAP after getting a trigger signal from one of a few=20
> sources, and then waking up.  USB will introduce another delay..
>=20
> On the other hand, I did mentally tinker with the idea of just stopping=20
> the clock on an R-Pi and shutting down most peripherals. On power up.a=20
> small PIC or other uC could re-power-up all peripherals on the Pi and=20
> re-start the clock to the R-Pi and it *should* be none the wiser.  But I=
=20
> still want to learn about video, so not pursuing this option currently.
>=20
> Cheers,
> -Neil.
>=20
>=20
> On 3/8/2018 7:10 PM, James Cameron wrote:
> > I'd look for a USB camera sensor with mpeg built-in, so that the host
> > CPU would only need;
> >
> > - a USB controller and stack,
> >
> > - an SD controller and stack,
> >
> > - a filesystem stack,
> >
> > - probing for the USB device and asking for the stream,
> >
> > - reframing the stream into whatever format is desired.
> >
> > An RTOS of some sort would be handy.
> >
> > A complete OS just makes it too easy, no challenge.
> >
> > For quick hackable prototypes, perhaps BeagleBone or a Raspberry Pi
> > Zero with camera.  The latter would take me about half an hour to
> > configure for the application described in this thread; camera to
> > microSD card.
> >
>=20
> --=20
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--=20
James Cameron
http://quozl.netrek.org/
--=20
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View/change your membership options at
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.