Re: [Gumstix-users] Need help on future purchase

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Thanks for the info.

It's hard to find any tantalum capacitors that are rated 20/25 Volts for case packaging C0805 to replace the standard 10V ones they have on that board; probably because of the size limit.  I might replace those caps with a case packaging of 3327 instead of the 0805, although further modification might be required for the increase in size.  The TPS6211 Converter has an input rating of 3.1-17 volts, so I believe the step-down converter itself can support a full 12 Volts itself as long as the caps are replaced.

Does anybody have any information bit resolution control of the PWMs??? 

-----Original Message-----
From: Chris MacDonald [mailto:ch...@fo...] 
Sent: Friday, November 20, 2009 4:26 PM
To: General mailing list for gumstix users.
Subject: Re: [Gumstix-users] Need help on future purchase

I take a shot at some of these...

The exposed logic on the expansion boards (ADCs, PWMs, RS232, etc.) is
all 1.8V. You'll need level translation/conversion if you want 3.3 or
5V. From memory the specs for the SoC specify 3 UARTs, two of which
are brought out to the expansion board, and one of those is used by
the ftdi serial-usb console port leaving only one left. As for
powering the board, I don't think it can do 12V; there are some caps
on the power regulation side that are rated only to 10V, at least
according to the tobi schematics
(http://pubs.gumstix.com/boards/TOBI/PCB30002-R2411/). From my
understanding the COMs themselves consume a bit under 1W for the
non-wireless versions and the wireless ones are a bit over 1W; I think
those numbers don't take the expansion boards into account... I'm not
sure.

You can load the SD card with almost any OS you'd like, though the
openembedded toolchain for bootloader/kernel/os image creation is
pretty nice and makes customizing your OS relatively painless (e.g. in
your case, including gcc on the COM os image). There are also
instructions on booting from an SD card
(http://www.gumstix.net/Setup-and-Programming/cat/Overo-Setup-and-Programming/111.html)
if that is the route you want to go.

Others can fill in any gaps or correct me if any of the above is wrong...

Chris

On Fri, Nov 20, 2009 at 1:03 PM, Charles Woloszynski
<cha...@ha...> wrote:
>
>
> Charlie
> Sent from my iPhone
> On Nov 20, 2009, at 3:39 PM, "Joshua Garcia" <jg...@eo...> wrote:
>
> Hello,
>
>
>
> My name is Josh, and I am a research engineer that is looking for guidance
> and suggestions on a possible future purchase of gumstix hardware.  However,
> the hardware that I will be purchasing has to meet the specific requirements
> below:
>
>
>
> ·         Ethernet Interface Connection
>
> ·         PWM functionality
>
> o   One PWM line at 3.3 V
>
> o   Another PWM line at 5.0 V
>
> o   Can output frequencies in the range of ¼ Hz to 20 Hz
>
> o   Fairly accurate (~ 1 ms accuracy)
>
> ·         At least two RS-232 serial connections
>
> ·         Accept a 12V input for power
>
> ·         Has linux as an operating system
>
> o   2.6.21-ts linux kernel or greater
>
> o   Ability to install an NTP server on the linux OS
>
> o   Ability to compile C++ and C source code right on the board itself
> through the use of an arm compiler
>
> ·         Can install Debian GNU as a linux interface for the computer
> on-module
>
> ·         Can use some kind of SD card to bootup with and load up our
> version of the linux we installed
>
> ·         Contains an open available port that provides system level control
> (could be serial, USB, ethernet, etc…)
>
> I had my eye on the Overo Earth and the expansion board, the Tobi.  Will
> these two pieces of hardware fulfill these requirements?  Is there a better
> hardware selection that you recommend over what I selected?
>
>
>
> A couple more questions that I had on my mind are:
>
>
>
> How much power roughly will these two pieces of hardware consume?
>
> What is the acceptable voltage range that powers the Overo Tobi?
>
>
>
> If anyone could help me out, it would be greatly appreciated.
>
>
>
> THANKS
>
>
>
> Joshua P. Garcia
>
> Research Engineer
>
> Sensor Technology Division
>
>
>
> Penn State Electro-Optics Center
>
> 222 Northpointe Blvd.
>
> Freeport, PA 16229
>
>
>
> Email: jg...@eo...
>
> Phone: (724) 295-7000 Ext. 7158
>
>
>
> www.electro-optics.org
>
>
>
> ------------------------------------------------------------------------------
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