Arduino Yún

Paul Boddie paul at boddie.org.uk
Thu Aug 22 15:55:54 EDT 2013


On Wednesday 7. August 2013 15.17.37 Werner Almesberger wrote:
> Paul Boddie wrote:
> > I wonder whether it would be possible to "rebase" the NanoNote on
> > [AR9331] hardware.
> 
> I would expect WLAN-centric chips/modules to be very constrained
> when it comes to peripherals. For example, the AR9331-AL1A doesn't
> have an LCD interface, seems to lack MMC completely, and so on.

I have to admit that I didn't really look very closely at the specifications 
or the openness of the AR9331, other than being generally skeptical about just 
about any hardware in both respects. What is encouraging is that there is 
supposedly complete Linux support for it, but it's difficult to say more 
without the full details, and those details (and product availability) are 
taking their time to arrive.

> I'd also question the wisdom of designing with a chip that's not
> fully documented.

I guess that's a risk a lot of people are taking these days. That the 
datasheet is "company confidential" is not really very encouraging, I agree. 
One can only hope that the Arduino people are not just tempted to treat the 
AR9331 as a black box (a bit like the various GSM modules), but instead seek 
to properly document that part of the device. It would seem a bit decadent to 
treat the Atheros chip as a black box that gives wireless capabilities to an 
Atmel microcontroller, ignoring the capabilities of the Atheros part as a 
general purpose computer in its own right, but if it's cheaper than other 
wireless chips and does the same job, it would be understandable from an 
economic perspective.

> For something Ya-like, I'd rather look at chips like Freescale's
> i.MX233 and i.MX283. They come with complete and publicly
> accessible documentation, pack a lot of peripherals, including
> voltage regulators, are fairly inexpensive, and are already
> supported by Linux. You can find other open designs using at least
> the i.MX23.
> 
> The i.MX283 is the clearly nicer choice, both in terms of
> capabilities and in terms of price, but it's only available as BGA,
> increasing the development cost. The i.MX233 is available in LQFP.
> 
> They run at "only" 454 MHz, but that's still plenty for a Ben-grade
> device.

There are established products that use the iMX233:

https://www.olimex.com/Products/OLinuXino/iMX233/

The attraction of a "volume" platform like Arduino is that lots of people will 
hopefully step up and take that platform in lots of different and interesting 
directions, and that the initial engineering will have been done. The above 
Olimex boards are interesting alternatives, although not nearly as well known, 
of course.

Paul



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