The issue I am having is, I was working with a circuit that was connected to a 12v power source and it may have short circuited... Before when I typed the command "echo 1 > value" to a particular gpio pin, and checked with "cat value" to see what its value was it would read "1". Now, it only reads "0"... I tested the voltage on the gpio pin in question and when set to 1, it reads 3.4v on the voltmeter and when set to 0 it reads 0, but the value in linux does not change from 0... I have tried reinstalling the OS on the sd card, but it didn't fix it... Did I fry the GPIO pins? If not how do i fix this...?
You cannot read the value from a output pin with "cat". You can only do that with an input pin. It is a known issue from the documentation:
@waltervl You are referring to the Neo's documentation while @tdeel has posted in the Quad subforum. I don't think Neo's documentation is applicable to the Quad's. Although I own a Quad, I haven't used the Arduino on it, so I can't help. I would try to use another non-suspect pin, see if it works there. And use the suspect pin as input pin and see if you can read a value from it.
I linked to the quad documentation. It is a Linux thing not Arduino. And no difference in behavior on the Neo or Quad. There is somewhere here on the forum a link to a Ubuntu site proving it. It could work but not guaranteed. So there is nothing wrong with your Quad. The output goes high when you put it high and goes low when you put it low. If you set the direction of the pin to input you can set 3.3V on it and then do cat value. Then put 0 V on it and read the value again. This should work. Do not make the error to just leave the input pin without a voltage (0 or 3.3V) because then you have an undefined situation (and outcome)
Thanks guys! I tested the input values using a sensor I have, and they seem to be working fine! I was sure i had killed it due to the fact that I could read the out values before the incident and not after.. maybe it was just a coincidence? Thanks for the help!
