Use eQEP on 4.4.23-ti-r51 kernel

[Theodosis Ntegiannakis]

Hello all,

I am trying to read a Quadrature Encoder with the Beaglebone Black using kenel  4.4.23-ti-r51 and Ubuntu.

I have enabled cape-universala
and also enabled pins P8_11 and P8_12 using:
config-pin P8_11 qep
config-pin P8_12 qep

But i cannot find "position" or "period" in the /sys/devices/platform/ocp/48304000.epwmss/48304180.eqep/
Is there something wrong i have done?
How can i read the position using python?

[Theodosis Ntegiannakis]

Just updated kernel to 4.4.31-ti-r67.
now i can find position and period in the /sys/devices/platform/ocp/48304000.epwmss/48304180.eqep/

but cat position keeps returning 0.

when trying to use other pins:
config-pin P8_33 qep  and
config-pin P8_35 qep
it returns invalid mode qep

the same in P8_41 and P8_42 ...

have anyone tried it? is it working?
I am not sure if it is not working or if i am looking wrong pins or my encoder doesnt work ok...
My encoder middle pin is hooked to GND and the other two pins in eqepA and eqepB respectively.

[Theodosis Ntegiannakis]

I am sorry for the multiple messages but I am finding new information every time!

eQEP just worked!
The only pins i could enable with config-pin though are P8_11, P8_12, P9_27, P9_92 (42B).
P8_33 and P8_35 still have the invalid mode qep.


Now my only problem is how to read position from python. Any help would be appreciated

[Dennis Lee Bieber]

On Sun, 13 Nov 2016 10:44:05 -0800 (PST), Theodosis Ntegiannakis
<tntegi...@gmail.com> declaimed the
following:

>
>Now my only problem is how to read position from python. Any help would be
>appreciated
>

Unfortunately it appears PyBBIO is still tied to 3.x kernels. Since it
had a library just for rotary encoders...
https://github.com/graycatlabs/PyBBIO/milestone/5
https://github.com/graycatlabs/PyBBIO/wiki/RotaryEncoder

You might be able to cobble something up from the source code (the
sysfs functions are in C, you might use slower Python I/O to replace them;
and if you are setting up the eQEP channel externally, avoid the loading of
dtbo)


Adafruit_BBIO does not mention rotary encoders at all.

--
Wulfraed Dennis Lee Bieber AF6VN
wlf...@ix.netcom.com HTTP://wlfraed.home.netcom.com/

[William Hermans]

It's a simple read. Learn how to read a file in Python, and your problem will be solved.

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[gibson.s...@outlook.com]

Do you remember how you got eQEP to work? Ours just reads 0