Beagle Bone black debain gpio access denied

[Hemant Kapoor]

Hello,

Yet another newbie question.

I have got latest debian image on my beagle bone black.
uname - r output: 4.9.45-ti-r57

and I noticed various gpio directory in /sys/class/gpio

when I tried
echo 69 > unexport
it gave me permission denied.
so I changed the permission of unexport file to be 666

and now when I try to use the same command it gives me an error:
-bash: echo: write error: Invalid argument

Can anyone please help...

Ultimately I want to develop a C++ project to toggle LED which is connected to one of the pins...

Any help regarding this matter is deeply appreciated.

Regards,
Hemant Kapoor

[Jeff Andich]

Switching to root before doing sysfs operations, (e.g. sudo su), typically seems to work for me..

[Hemant Kapoor]

Hello,

Thanks for the response...

I did manage to sort the issue by performing two steps:

a. Added a udev rule to make gpio accessible
b. Added user to gpio group...

Regards,
Hemant Kapoor