Thanks Andrew.
I did the following:
1) edit /etc/rc.local (sudo nano /etc/rc.local)
2) added the following 2 line near the end, but in front of the last line (exit 0)
chgrp -R dialout /sys/class/gpio
chmod -R g+rw /sys/class/gpio
3) saved file
4) rebooted
This allowed me to do the shell commands with out needing to add the “sudo” and to do livecode I/O.
Playing with livecode I/O I have learned the following:
setting the defaultfolder to “/sys/class/gpio/gpio12”
put the files…. gets me what I expect. I see the direction and value files as well as some others that I have yet to explore.
putting the defaultfolder returns “/sys/device/virtual/gpio/gpio12”
Hummm, can livecode do I/O to virtual devices? Kind of…..
These do NOT work:
put URL “/sys/class/gpio/gpio12/value” or
put 0 into URL “/sys/class/gpio/gpio12/value”
open file “/sys/class/gpio/gpio12/value” for write
write 0 to file “/sys/class/gpio/gpio12/value”
wait 1 second
write 1 to file “/sys/class/gpio/gpio12/value”
close file “/sys/class/gpio/gpio12/value”
— I suspect that the virtual driver keys off of the close to actually output the signal.
This works quite well:
open file “/sys/class/gpio/gpio12/value” for write
write 0 to file “/sys/class/gpio/gpio12/value”
close file “/sys/class/gpio/gpio12/value”
In fact it can be pretty fast, I could not see any blinking at all with _delay set to 0, 1 was flicker, 2 was the start of a true blink, 3,4,5 were solid blinks.
on mouseup
repeat with _delay = 0 to 5
repeat 10 times
_output 0
wait _delay ticks
_output 1
wait _delay ticks
end repeat
end repeat
end mouse up
on _output val
open file “/sys/class/gpio/gpio12/value” for write
write val to file “/sys/class/gpio/gpio12/value”
close file “/sys/class/gpio/gpio12/value”
end _output
Using the shell cmds were way too slow. Not even close to the performance of open, write, close.
Hope this helps someone else playing with Raspberry Pi
Regards,
Mike
Post by Andrew KlutheNo specific information I can help with but this seems like it might hold
some answers for you if you dig enough.
http://www.raspberrypi.org/forums/viewtopic.php?f=44&t=73924
Post by Michael DoubI think that I have now confirmed that it is a permission issue. I added
a “sudo” in front of the “echo” command. Now everything seems to be
working.
I still have the question about how to give livecode the correct
permissions to access this files as it would seem more logical to use to do
direct IO to the files rather that to be forced to use a shell command.
I am running as the default pi user. Should this user have different
permissions? If so how do you grant them?
Regards,
Mike
Post by Michael DoubI am looking for some help from some of you with unix/raspberry pi
experience.
Post by Michael DoubI have think that I have installed 7.0 rc 1 on my raspberry pi B+
properly. I am trying to figure out how to play with the GPIO’s.
Post by Michael DoubI am am able to execute the following to set up the IO
put shell("echo 12 > /sys/class/gpio/export") into dummy
put shell("echo out > /sys/class/gpio/gpio12/direction") into
dummy
Post by Michael Doubbin/sh: cannot create /sys/class/gpio/gpio12/direction: Directory
nonexistent
Post by Michael DoubWhen I use the terminal, I can see that the directory does exist and I
am able to modify the contents to both set the IO direction and sucessfully
turn the LED on and off.
Post by Michael DoubCould it be that I do not have the permission to create directories and
modify files from livecode? How can I check this from livecode and fix
it? …. assuming this is in fact a permission issue.
Post by Michael DoubThanks,
Mike
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Regards,
Andrew Kluthe
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