I have a strange behaviour when using GPIO pins on raspberry PI. I log as root (sudo so) and type following commands to set pinout values:
root@raspberrypi:/home/pi# echo 3 > /sys/class/gpio/export
root@raspberrypi:/home/pi# echo out > /sys/class/gpio/gpio3/direction
root@raspberrypi:/home/pi# echo 0 > /sys/class/gpio/gpio3/value
If I read the content of /sys/class/gpio/gpio3/value, I get the exact value I wrote before (as I expected). Anyway, voltage on the output is not affected. It seems to me that Linux does not actually write any value on the output gate.
Any suggestion? Thanks for your help. (and sorry for by bad english )