SPI over GPIO

[Tirtha Ghosh]

Have you try setting GPIO direction to out before writing to it???
give a shot.

follow: http://sites.google.com/site/bifferboard/Home/gpio



On Fri, Mar 11, 2011 at 4:04 PM, Alexandru Caramida <
alexandruc1723 at yahoo.com> wrote:

> Hello everyone,
>
> I am trying to emulate an SPI interface using four GPIO pins. This is a
> desktop computer with linux 2.6.28 kernel.
>
> The problem is I don't know if the pins are working. I read that if I have
> the sysfs support for the kernel (which I do :D) all I have to do
> is enable the respectiv pin using
>
> echo N > /sys/class/gpio/export
>
> And I would get a gpioN directory
>
> But I always get: "write error : invalid argument."
>
> Is there some other option i need to enable first? The people I am working
> with assured me that these pins are not used by any other device and they
> haven't found anything to suggest that they were turned off manualy.
>
> Please help,
>
>
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20110311/aa8f3f7c/attachment.html