Thanks, I got it.  Can someone point me in a better direction with respect to GPIO?
From my wikipedia read, GPIOs are typically grouped into 8 pins. It doesn't help that I just don't have the technical expertise to understand some of this as well as I should.
My best guess is that '4 GPIO' refers to the 4 unused UARTS on the board.  There is a BTUART, two HWUARTs, a FFUART and a STUART for a total of 5 UARTS.  As the GPS is using the STUART as a serial port the '4 GPIO' would refer to the 4 remaing UARTS.
If I wanted to vary the voltage on one of those 4 UARTS I suspect I could stick my volt meter on the GND and one other pinout (TXT or RXD) for a given UART and then do something like:
echo "GPIO out set" > /proc/gpio/GPIO??
and I would now show 3.3 volts.
echo "GPIO out clear" > /proc/gpio/GPIO??
would then drop the voltage back to 0
I don't see how to relate a particular GPIO to a particular pinout on a UART and I think there is a good chance I am just totally misunderstanding something.
I think the alternative would be that I need to do something like
echo "AF2 in" > /proc/gpio/GPIO46
echo "AF1 out" > /proc/gpio/GPIO47
This would turn the STUART on as a serial device.  I could then do something like a dump of /dev/zero to /dev/ttys? and I would then see the change in voltage between GND and TXT or RXD.  I'm not sure how I relate a serial device to a given UART though?
Thanks for any pointers.

From: Rizal Nor <>
To: General mailing list for gumstix users. <>
Sent: Tuesday, April 28, 2009 9:48:10 PM
Subject: Re: [Gumstix-users] GPIO

Oh yeah, if you click on the Audiostix, under readme, you can see that GPSstix uses version R791 under audiostix.

"The original audiostix boards were built using PCB0006 (version R162)
The revised audiostix (audiostix2) and the GPSstix use PCB00012 (version R791)"

On Tue, Apr 28, 2009 at 9:41 PM, Rizal Nor <> wrote:
I don't know about the GPS stix, but some of the schematics are available at the link below.
I think the GPS stix is there as can check it out.

On Tue, Apr 28, 2009 at 9:16 PM, Donald Shrum <> wrote:

I have a Verdex pro XL6P and a GPS stix.  Can anyone point me to a link that explains where on the circuit board the 4 GPIO ports are.  A schematic?  Anything?  Am I the only one that has a hard time finding information on the wiki site?







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Joey aka. Rizal
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Joey aka. Rizal
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