Re: [Gumstix-users] Questions about Thumbo, Verdex Pro

[Ash C. <ash...@gm...>]

Hi Mark,

On Mon, Feb 27, 2012 at 3:09 PM, Mark Zieg <mar...@oc...> wrote:
> Q) The product page states that the Thumbo can be used with "any Overo COM
> without on-board wireless communications...such as the Overo Air COM or
> Overo Fire COM, [which] can draw more than 500mA".  My question: can you use
> an Overo Fire COM as long as you're not enabling WiFi/Bluetooth, or are
> these COMs totally incompatible with the Thumbo regardless of which features
> you enable?  (I ask because we have several extra Fire COMs already, which
> I'd like to repurpose for testing.)
Feel free to use the Fire COMS.  They aren't incompatible---the
wireless just sucks down lots of power.
>
> Q) The product page says it has a "USB standard A plug with OTG signals
> (wired as a device)" -- does the mention of OTG mean that I can use the
> Thumbo as a USB Host, as long as I provide the standard-A gender-mender and
> provide external power?  Can I provide 5V power directly to the pins on the
> USB port, assuming I'm already providing my own battery pack and charger?
yes.
>
> Q) The product page lists "level shifters for use with a set of test pads"
> -- can these "level shifters" allow us to use the 1.8v signal logic on the
> 60-pin header to communicate with a 3.3v card elsewhere in the system?
I think the answer is 'yes' but it may depend on your exact
configuration. http://pubs.gumstix.com/boards/THUMBO/PCB30021-R2666/
(page 6 of the schematic) provides the best reference.

>
> Q) Of the 60 1.8V signal pins, can the two "two-wire serial ports" be used
> as a UART?
Yep. (as long as you don't need hardware flow control etc.)
>
> Q) Of the 60 1.8 v signal pins, can the "one 1-wire port" be used as a gas
> gauge for communicating with a battery circuit?  That is, does it support TI
> HDQ?
Yes.
>
> Q) The SPI bus is 4-wire?
MOSI, MISO, a clock, two chip selects, and an interrupt (some
applications with SPI use an interrupt).
>
> Q) Sadly, it looks like the 60-pin board only provides a single SPI bus,
> whereas I think I need two (one to control our sensor, and another to
> command the text display I'd originally identified).  I suppose I could try
> the 40mm x 35mm NHD-0208AZ-RN-YBW-33V, though I'm still trying to make sense
> of its pin-out.
>
> Verdex Pro XL6P + Console-VX + NetPro-VX Questions
>
> Notes:
> - according to the Verdex features, I can pull some serious UART action on
> these
>
> Q) I assume I can build micro-SD images for the Vertex much like I do for
> the Overo COMs, just using different images?  Somewhat worrisomely, I don't
> see much on Sakoman.com for Vertex.  Is there an equivalent image store
> elsewhere?  (I don't necessarily need to update these to Ubuntu, but I'm not
> sure how long they've been in that closet, so I suspect I might want to
> refresh whatever I find on there.)
The software for verdex is, in general, based on much older kernels
(2.6.21 and 2.6.31).  It is possible to build it using OE but I'd say
Overo is better supported these days. Unless you have a particular
reason, I'd use Overo for new designs.
>
> Q) I assume the USB mini-B connector on the Console-VX can mount a
> thumbdrive storage device, using a mini-B-to-A-receptacle adapter?
>
> Q) This thing seems to have an insane number of available pins, but I'm not
> seeing an explicit "SPI bus" mentioned in the pin-outs.  Can such be found
> along one of these expansion boards?  (I do see some archive messages about
> people successfully getting the SPI demo to work on the Verdex, so I assume
> it's doable, I'm just not sure which pins they're using.)
I suspect this is possible but I haven't tried personally.  There is
some mention of SPI in the PXA270 manual but bit-banging may likewise
be an option.
>
> Otherwise, while the stacked Verdex boards are closer to a hand-held
> form-factor than the Chestnut, they're still vastly larger than the Thumbo,
> so I'd really prefer to get that working if I can support power in, display
> out, SPI out, and UART in (can lose the USB in a pinch).

HTH,
-Ash