March 11, 2011
10:34 a.m.
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,