gumstix

Hi Eric,

>  Quick little problem to deal with here: does anyone have some
> recommendations on a simple circuit to supply 5V to a gumstix/robostix
> stack?
>
>  Currently I'm using a 7805 regulator with some caps and a fuse connected=
 to
> a +9V battery in.  It supplies the correct voltage, ~+5.044V, when the
> gumstix isn't plugged in, but when it is plugged in, the voltage drops to
> +4.7V and starts causing segmentation faults on the robostix when I run
> i2c-io.  So I tried ramping the input voltage up to +12V, since the
> regulator should be able to take this, but the 7805 gets extremely hot in=
 a
> very short time.  I checked the current when it's running, and the
> gumstix/robostix stack (and a wifi cf card) seems to draw ~450mA, way too
> much for this circuit.
>
>  What are you guys using?  Anyone have some some suggestions for somethin=
g
> else than a 7805, which seems like it can't supply enough current?  Any h=
elp
> would be greatly appreciated...

The robostix has onboard regulators already. +12 is a bit on the high
side, but +9 should be OK.

5v is too low (since the voltage regulators which are on the board try
to output 5v but need a bit more for headroom.

In particular, the MIC5219 regulator on the board can drop as much as
600mV depending on the amount of load. So you need 5.6v or higher.

There are a total of four voltage regulators on the robostix. One of
them is dedicated for the gumstix. However its only rated at 500 mA,
so if your CF card will draw 450mA then that's too much.

What you can do is to take the input to your 7805 and connect it to
the robostix power and take the output of your 7805 and connect it to
the power on the cfstix. This way you'll get 500mA from the robostix
power supply, and whatever your 7805 is rated at from it.

You want your input to the 7805 to be a minimum of 7.2v (so it has
2200mV dropout), but as close to 7.2v as you can. Perhaps 7 1.2v
batteries for a nominal 8.4v.

Better yet, use a low-dropout regulator like the LM2940 which has a
500mV dropout voltage, and is available in the same package as the
7805. Then you could use 6 1.2v NiMH or NiCAD batteries.

--
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/

Thanks, those are great ideas, I'll try em out this evening...

On 4/24/06, Dave Hylands <dhylands@...> wrote:
>
> Hi Eric,
>
> >  Quick little problem to deal with here: does anyone have some
> > recommendations on a simple circuit to supply 5V to a gumstix/robostix
> > stack?
> >
> >  Currently I'm using a 7805 regulator with some caps and a fuse
> connected to
> > a +9V battery in.  It supplies the correct voltage, ~+5.044V, when the
> > gumstix isn't plugged in, but when it is plugged in, the voltage drops
> to
> > +4.7V and starts causing segmentation faults on the robostix when I run
> > i2c-io.  So I tried ramping the input voltage up to +12V, since the
> > regulator should be able to take this, but the 7805 gets extremely hot
> in a
> > very short time.  I checked the current when it's running, and the
> > gumstix/robostix stack (and a wifi cf card) seems to draw ~450mA, way
> too
> > much for this circuit.
> >
> >  What are you guys using?  Anyone have some some suggestions for
> something
> > else than a 7805, which seems like it can't supply enough current?  Any
> help
> > would be greatly appreciated...
>
> The robostix has onboard regulators already. +12 is a bit on the high
> side, but +9 should be OK.
>
> 5v is too low (since the voltage regulators which are on the board try
> to output 5v but need a bit more for headroom.
>
> In particular, the MIC5219 regulator on the board can drop as much as
> 600mV depending on the amount of load. So you need 5.6v or higher.
>
> There are a total of four voltage regulators on the robostix. One of
> them is dedicated for the gumstix. However its only rated at 500 mA,
> so if your CF card will draw 450mA then that's too much.
>
> What you can do is to take the input to your 7805 and connect it to
> the robostix power and take the output of your 7805 and connect it to
> the power on the cfstix. This way you'll get 500mA from the robostix
> power supply, and whatever your 7805 is rated at from it.
>
> You want your input to the 7805 to be a minimum of 7.2v (so it has
> 2200mV dropout), but as close to 7.2v as you can. Perhaps 7 1.2v
> batteries for a nominal 8.4v.
>
> Better yet, use a low-dropout regulator like the LM2940 which has a
> 500mV dropout voltage, and is available in the same package as the
> 7805. Then you could use 6 1.2v NiMH or NiCAD batteries.
>
> --
> Dave Hylands
> Vancouver, BC, Canada
> http://www.DaveHylands.com/
>
>
> -------------------------------------------------------
> Using Tomcat but need to do more? Need to support web services, security?
> Get stuff done quickly with pre-integrated technology to make your job
> easier
> Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronim=
o
> http://sel.as-us.falkag.net/sel?cmdlnk&kid=120709&bid&3057&dat=121642
> _______________________________________________
> gumstix-users mailing list
> gumstix-users@...
> https://lists.sourceforge.net/lists/listinfo/gumstix-users
>

Hi Dave, quick confirmation on what you recommended:

I can plug anywhere from +5 to ~+9 into the V-Board connector on the
robostix, powering that board?  Then I'll can just have my regular 7805
delivering +5.00V to the CFstix/Gumstix combination?

9V ---> |robostix|=3Dhirose=3D|gumstix/cfstix| <---5V

?
Thanks again,

Eric


On 4/24/06, Dave Hylands <dhylands@...> wrote:
>
> Hi Eric,
>
> >  Quick little problem to deal with here: does anyone have some
> > recommendations on a simple circuit to supply 5V to a gumstix/robostix
> > stack?
> >
> >  Currently I'm using a 7805 regulator with some caps and a fuse
> connected to
> > a +9V battery in.  It supplies the correct voltage, ~+5.044V, when the
> > gumstix isn't plugged in, but when it is plugged in, the voltage drops
> to
> > +4.7V and starts causing segmentation faults on the robostix when I run
> > i2c-io.  So I tried ramping the input voltage up to +12V, since the
> > regulator should be able to take this, but the 7805 gets extremely hot
> in a
> > very short time.  I checked the current when it's running, and the
> > gumstix/robostix stack (and a wifi cf card) seems to draw ~450mA, way
> too
> > much for this circuit.
> >
> >  What are you guys using?  Anyone have some some suggestions for
> something
> > else than a 7805, which seems like it can't supply enough current?  Any
> help
> > would be greatly appreciated...
>
> The robostix has onboard regulators already. +12 is a bit on the high
> side, but +9 should be OK.
>
> 5v is too low (since the voltage regulators which are on the board try
> to output 5v but need a bit more for headroom.
>
> In particular, the MIC5219 regulator on the board can drop as much as
> 600mV depending on the amount of load. So you need 5.6v or higher.
>
> There are a total of four voltage regulators on the robostix. One of
> them is dedicated for the gumstix. However its only rated at 500 mA,
> so if your CF card will draw 450mA then that's too much.
>
> What you can do is to take the input to your 7805 and connect it to
> the robostix power and take the output of your 7805 and connect it to
> the power on the cfstix. This way you'll get 500mA from the robostix
> power supply, and whatever your 7805 is rated at from it.
>
> You want your input to the 7805 to be a minimum of 7.2v (so it has
> 2200mV dropout), but as close to 7.2v as you can. Perhaps 7 1.2v
> batteries for a nominal 8.4v.
>
> Better yet, use a low-dropout regulator like the LM2940 which has a
> 500mV dropout voltage, and is available in the same package as the
> 7805. Then you could use 6 1.2v NiMH or NiCAD batteries.
>
> --
> Dave Hylands
> Vancouver, BC, Canada
> http://www.DaveHylands.com/
>
>
> -------------------------------------------------------
> Using Tomcat but need to do more? Need to support web services, security?
> Get stuff done quickly with pre-integrated technology to make your job
> easier
> Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronim=
o
> http://sel.as-us.falkag.net/sel?cmdlnk&kid=120709&bid&3057&dat=121642
> _______________________________________________
> gumstix-users mailing list
> gumstix-users@...
> https://lists.sourceforge.net/lists/listinfo/gumstix-users
>

Hi Eric,

>  I can plug anywhere from +5 to ~+9 into the V-Board connector on the
> robostix, powering that board?  Then I'll can just have my regular 7805
> delivering +5.00V to the CFstix/Gumstix combination?
>
>  9V ---> |robostix|=3Dhirose=3D|gumstix/cfstix| <---5V

Yeah - that looks right.

the V_BATT on the hirose connector will have 500mA from the robostix
voltage regulator plus whatever you can feed in from the cfstix.

On all of the other boards, the power connector is the same as V_BATT.
The robostix is the exception, where V_BATT comes from a 500mA voltage
regulators.

The regular boards also can't take 9v.

If its at all possible use less than 9v. Everything above the
regulated voltage is dissapated as heat by the voltage regulator, so
the lower the 9v voltage is, the less heat will be generated.

--
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/

Bashir, Yasir a =E9crit :
> I am new to this. This is a very basic question but I have not been abl=
e=20
> to find an answer. If I have Connex 400mx-bt, NetMMC and breakout-gs,=20
> what=92s the easiest way to connect to Linux from a Windows XP workstat=
ion?

To get access to U-Boot you will need the serial port from the breakout.
Then Ethernet is by far the easiest way to go (I did not even try to use
usbnet or BT ;)

Have fun,

			Lqurent

Thanks for asking, Erik.


Yes, we have announced audiostix2 and GPSstix boards today. We have 
put together a "GPSstix/audiostix2 FAQ" that may answer several of 
your questions:

http://www.gumstix.org/tikiwiki/tiki-view_faq.php?faqId=18




At 10:50 AM -0700 4/25/06, Erik D. Rodriguez wrote:
>Looks like the Audiostix 2 is finally available on the web site. 
>This is very good news, just what I have been waiting for. So, enter 
>the questions. I read through the history and there was quite a bit 
>of discussion about some of the technical aspects of the A2, 
>including voltages and charging. I looked at the schematics online 
>and did not quite get the answers I hoped for. So, could someone 
>please say what is/is not on the A2?

answered here:

http://www.gumstix.org/tikiwiki/tiki-view_faq.php?faqId=18#q357




Don







====================================================================

Don Anderson		http://www.gumstix.com

====================================================================
--

Mark Sayer escreveu:

> Further information on my little problem:
>  
> The following code demonstrates my problem. This is a simple program 
> that opens . and uses fcntl to set a sigio if the directory or any 
> files are modified. On my Fedora system, everytime a write is 
> performed on a file in this directory, it calls handler(). On the 
> gumstix, it just comes up with the same fcntl error message: "Invalid 
> argument".
>  
> I found the fcntl man page for uClinux and it is exactly the same as 
> Fedora - not that this necessarily means anything. I dunno.


Gumstix uses standard linux, not uClinux; However, it's quite tunned for 
space usage, so I guess some resources aren't compiled in onto the 
kernel. I'm sure that inotify is out, but not sure about dnotify and 
friends.

Perhaps you should attempt recompiling it? Look for options named as 
"something-notify" or alike, I don't have the buildroot to look at it 
right now.

Good luck!

Alexandre