GPIO on Beaglebone Black

Question

I'm currently stuck on a problem with GPIO pins with the Beaglebone black.

I am looking for a proper way to read the values from GPIO pin p8_4 in C. I tried to use a library which used an old not supported way from the time before device tree's where introduced, if I understand this correctly.

I tried to find other solutions to my problem but I can't seem to find one. Is there anyone who can get me on the right track in C?

Did you get your problem solved? – S.I.J Dec 14 '15 at 10:49 — S.I.J, Dec 14 '15 at 10:49

score 9 · Accepted Answer · edited Jun 18 '20 at 10:17

9

Here is a C code:

#include <stdio.h>


int main()
{
    FILE *io,*iodir,*ioval;

    io = fopen("/sys/class/gpio/export", "w");
    fseek(io,0,SEEK_SET);
    fprintf(io,"%d",39);
    fflush(io);

    iodir = fopen("/sys/class/gpio/gpio39/direction", "w");
    fseek(iodir,0,SEEK_SET);
    fprintf(iodir,"out");
    fflush(iodir);

    ioval = fopen("/sys/class/gpio/gpio39/value", "w");
    fseek(ioval,0,SEEK_SET);

    while(1)
    {
        fprintf(ioval,"%d",1);
        fflush(ioval);
        sleep(1);
        fprintf(ioval,"%d",0);
        fflush(ioval);
        sleep(1);
    }

    fclose(io);
    fclose(iodir);
    fclose(ioval);
    return 0;
}

Be sure to do proper error checking.

Follow Derek Molloy's website on Beaglebone His site

edited Jun 18 '20 at 10:17

Mixaz

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answered Dec 14 '15 at 07:26

S.I.J

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I've changed my previous code as this is one is more generic. – S.I.J Dec 14 '15 at 07:33
Currently testing the problem, but it seems to work! Thanks! – Joris Mathijssen Dec 14 '15 at 12:45
"Follow Derek Molloy's website on Beaglebone"... yeah, but that's nothing but videos, as if Derek is typing-challenged or something. Videos are a NASTY way to learn how to do things. – TDHofstetter Aug 29 '20 at 21:36

GPIO on Beaglebone Black

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