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How to access timers in BeagleBone White from user side

Don Chakkappan
Prodigy 230 points

Hai everyone

   

                                  I got some relevant information regarding driver usage  from this link  . But how can i access timers in BeagleBone white from user side (using JNI).

I am working Android JellyBean4.1.2 (Linux kernal version 3.2) .

Is it possible by "cat"  any of the file in the following image ?

I need to count the pulses arriving in timer pin.

How can i do it  ?

  • 0
    Mastermind 9310 points
    Hi Don,

    I do not think the timer exposes anything in the /sys folder.
    The omap_timer seems to be only reachable from the kernel, this means that you would need to write a driver for exporting this to the userland.

    From what I understand, you could also take a look at the ecap (which is made for event counting), but there is currently no driver for counting yet, only pwm mode.
  • 0 in reply to Adeneo Embedded support team
    Prodigy 230 points

    Thanks Adeneo Embedded Support team .

    Now i am working on user space driver development for BBW timer.

    Any helpful suggestions/guidelines/links much appreciated .

  • 0 in reply to Don Chakkappan
    Mastermind 9310 points

    Hi Don,

    I am not sure I understand what your are trying to do when you mention "user space driver".
    Let us know if you have any specific question.

  • 0 in reply to Adeneo Embedded support team
    Prodigy 230 points

    Dear Adeneo Embedded support team

                                                    I am working with AM3359ZCZ processor  on BeagleBone White . The OS running is Android JellyBean 4.1.2 (Kernal Version 3.2) .

    I have some hardware setup like DC pulses are the input of  Timer4  of  AM3359ZCZ  (Threshold is 3.3 volt signals).

    I have to count the pulses arriving in one second , since i can calculate the frequency of pulse generated.

    In the firmware side JNI is used for accessing the module from user space .

     Modules like GPIO , PWM are accessing from user side using fcntl.h (open(),close(),read(),write())  ; The user guide to access the modules provided in this link.

    I have to develop some similar mechanism for accessing the Timer to get the pulse count .  But i think there is no user guide (no built-in user space driver for dmTimer) . But some APIs are there for dmTimer in this link .

    So , i need to develop  a user space driver , since i can access the data arrived in the timer4 of  AM3359ZCZ  by simply calling open(), close() , read() ,write () . etc.(almost same as character device driver)

    But i am totally a green-horn in driver development. I have created a HelloWorld driver by googling. Now i am trying to develop the mentioned driver.

    Your great suggestions/feedback/guidelines much appreciated . Lot of thanks in advance . . .  

  • 0 in reply to Don Chakkappan
    Mastermind 9310 points

    Hi Don,

    What you are asking is a bit to generic and cannot be explain within a forum post, but rather requires training.
    I would suggest reading the LDD3 book available online to get used to kernel driver development: http://lwn.net/Kernel/LDD3/
      
    Also, we do not support beaglebone white, only am335x EVM, Starter kit and beaglebone black.