• State Resolved
  • Locked Locked
  • Replies 7 replies
  • Subscribers 98 subscribers
  • Views 176 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Getting high speed data

Fatih Ozay
Prodigy 180 points
Other Parts Discussed in Thread: TPS65950

How can i get high speed data on OMAP 3530? with which interface? By the way i try to obtain video data on beagleboard with at least 2 mbps.

 

Fatih

  • 0
    TI__Intellectual 2655 points

    Fatih,

     

    OMAP35x has various configurable peripherals, you could try GPMC or USB interface for getting to get High speed data transfer.

    What is bandwidth you are looking for & what are other requirements in terms of latency (real time traffic)?

  • 0 in reply to vaibhav
    Prodigy 180 points

    Hello vaibhav;

     

        I need real time transfer because i am going to use beagleboard with another encoder chip in order to transfer HD broadcast. So i need larger bandwidth like at leas 2 mbps and of course real time :) 

     

    Fatih

  • 0 in reply to Fatih Ozay
    Genius 3685 points

    Hi Fatih,

    In this case I would go for either a SPI or McBSP connection depending on the exact interface on your encoder chip/device? These can both to to ~48mbps with McBSP being hard realtime, while SPI is more soft realtime.

    Using the GPMC bus for this would give you a bandwidth of 100MB+ which I would  consider "overkill" since only 2mbps is needed :-)

    Best regards - I hope this helps you forward?
      Søren

  • 0 in reply to Soren Steen Christensen
    Prodigy 180 points

    Hi Soren;

        I am planning to use McBSP but i couldnot deal with McBSP. i just succeeded to compile kernel with McBSP support enabled. However i couldnot find what the further steps are and what should i do next to use mcbsp. And what do you mean by saying hard time real time and soft time real time?

     

    Fatih

  • 0 in reply to Fatih Ozay
    Genius 3685 points

    Hi Fatih,

    With respect to using McBSP. The kernel only contains a set of functions for simplifying McBSP usage. In order to use this for any real life application you need to write your own device driver utilizing these function-calls for providing an interface for upper layer user-land applications. One place of starting would be looking into how the ALSA driver utilizes the McBSP functions for sending data to the TPS65950 companion device...

    With respect to hard contra soft real time. What I mean is that both interfaces can easily transfer 2Mbps. With SPI you would most likely use a transfer frequency for i.e. 24MHz and transfer data in blocks/bursts in around 8% of the time giving an effective over all bandwidth of ~2Mbps (soft real time). In order to achieve the same using McBSP you would program it to transfer data with a 2Mbps speed and have it running 100% of the time (hard real time).

    Basically it's a matter of how the slave device expect the data to be transferred. If it's kind of streaming the data (McBSP) or have some internal buffer which would allow for a chunk of data to be received and the afterwards transferred to the OMAP (SPI)...

    Both buses would do the job, but with SPI you will have varying time between the different burst of data, while the McBSP is ticking at the same phase all the time...

    Hope the difference is clear? Best regards - Good luck
      Søren

  • 0 in reply to Soren Steen Christensen
    Prodigy 180 points

    Hi Soren;

        Thanks a lot for your answer. This is quite different but can you tell me the mcbsp functions you were mentioned. or at least some of them. I confused about it did you mean the functions inside /plat-omap/mcbsp.c.   

       Then if yes just including /plat-omap/mcbps.h give me the permission to reach them or should i do something more?

     

    Fatih

  • 0 in reply to Fatih Ozay
    Genius 3685 points

    Hi Fatih,

    Sorry for not getting back to you on this, but the last weeks have been extremely busy. I'm however glad the see that you are currently moving forward and getting good help from the BealgeBoard list (http://groups.google.com/group/beagleboard/browse_thread/thread/3bd82e9366875c89/1034167308158707?lnk=raot&fwc=1). Let's hereby  move this questions to the beagle mailing list for future references...

    Best regards - Good luck
      Søren