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 < [email protected]> 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 > [email protected] > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > >
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