Hi Soren,


I saw your comment about unidirectional GPIO on the OMAP (thanks).   I searched through the OMAP data sheet, and only found one unidirectional GPIO on J4, none on J1 (I didn’t look at J5 because we’re not using it).   That pin is GPIO_114 and it is INPUT only.   On the Overo connector pinout, they label this as GPIO114_SPI1_NIRQ.    Do you know what the SPI_NIRQ function is doing?    


Also, do you know if the mode number of each pin can be modified individually?






From: Søren Steen Christensen [mailto:lists@ssc-solutions.dk]
Sent: Thursday, May 13, 2010 1:00 PM
To: 'General mailing list for gumstix users.'
Subject: Re: [Gumstix-users] GPIO confusion


Hi James,


The Special stuff around GPIO0-GPIO31 is that they are in the WAKEUP-domain (always on) and thereby able to wake-up the CPU from its lowest level power state as opposed to the other GPIOs, which need to have the PER-domain active in order to wake up the system. More info about this can be found in the OMAP3530 TRM chapter 4 and 25 (spruf98f.pdf)…


Apart from the domain difference all GPIOs are identical – Though take care: A few GPIO can only be used as either Input or Output – More information on this can be found in the ball-description for the OMAP3530 in the Datasheet (omap3530.pdf).


Best regards – Good luck with your design




SSC Solutions ApS - Denmark - www.ssc-solutions.dk


From: Gordon Kruberg [mailto:gordon@gumstix.com]
Sent: Wednesday, May 12, 2010 7:15 PM
To: gumstix-users@lists.sourceforge.net
Subject: Re: [Gumstix-users] GPIO confusion



I have reviewed the documents and see they should be corrected on this point to say:

On revs  2173 -- 2516: J1 pin 9 is GPIO0_WAKEUP; GPIO31 goes to a test point on the board only.
On revs  2602 --     : J1 pin 9 is GPIO31_WAKEUP  GPIO0 is used as the IRQ from the TPS65950.


Can anyone confirm that the GPIO31_WAKEUP pin (J1 pin 9) is ok to use
as a normal GPIO (on a Palo43 board) please?
It is marked as 'SPECIAL USE' in the signals pdf, and is not set up by
default in board/overo/overo.h
Can anyone from Gumstix confirm what is special about this pin??
On Mon, May 10, 2010 at 5:25 PM, James Adams <james.r.adams@gmail.com> wrote:
Hi All,
I am designing a custom base-board to take a gumstix module
(eventaully) but am trying to wire up some extra buttons and a (simple
4-way plus centre click) joystick to GPIOs. I am using a Palo43 board
and soldering on buttons for now to get the software started, before
the custom base board is manufactured. (The idea is that the button
GPIOs that I use will not have to change from the initial Palo system
to the custom system...)
I am finding the whole 'is a GPIO available and actually free to use'
thing quite difficult, as there are various errors / inconsistencies
between the board schematic / web based signals doc and the pdf
signals sheet...
There seem to be 3 sources of information, the board schematic(s), the
web-based pin list(s) here:
and the pdf doc here
I know some of these errors have been reported before, but here's my
list for the record:
GPIO31_WAKEUP is erroneously marked as GPIO0_WAKEUP on Palo43
schematic and silkscreen, and web signals list.
GPIO10_TS_IRQ is erroneously marked as GPIO127_TS_IRQ on Palo43
schematic and silkscreen.
GPIO186_GPS_PPS is erroneously marked as GPIO128_TS_IRQ on Palo43
schematic and silkscreen.
GPIO148_TXD1 is erroneously marked as 158.TXD1 on Palo43 silkscreen.
Note that GPIO31_WAKEUP in the signals pdf is marked as (*) SPECIAL
USE - can I use it? What is this special use? It seems to work ok
using dev2mem to prod the config register then export the gpio in
sys/class/gpio... (which is how I;ve been testing all of these GPIOs
so far...)
My list of GPIOs I wish to use (and seem to work as far as I can test
from the console) are below - I would be most grateful if people could
take a look and let me know if any of them aren't suitable to be used
as a general purpose GPIO on the Palo43 board??
Any help much appreciated.
Note if there is an errata list that I have missed then apologies, I
am new to using the Gumstix stuff, however the GPIO31_WAKEUP
/GPIO0_WAKEUP inconsistency still exists between the web docs and the
pdf signals doc and needs fixing?
Kind Regards,
gumstix-users mailing list

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