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dm6467 USB host

VTR
Prodigy 130 points
Hi, I am novice at dm6467. As I understand that USB host of the dm6467 is very limited because it is not EHCI and use endpoints in host mode. Is it possible to connect about ten devices to it through USB hubs? Have anybody some experience with big USB tree and DaVinci?
  • TI__Mastermind 37340 points

    The features and limitations of the USB driver are detailed in the PSP release notes (e.g. ReleaseNotes_DM646x_Linux_PSP.pdf) which are included as part of the DVSDK.  I believe the limitation in the number of devices that can be supported are based on the types of devices; certain devices use an entire end-point while others share nicely.  A software work-around can probably be implemented for this, although I am not sure how huge of a task this would be.  Please note that the PSP release notes pertain to the software driver support; the hardware may be capable of more and those details are normally found in the corresponding user guides.

    http://focus.ti.com/dsp/docs/dspsupporttechdocsc.tsp?sectionId=3&tabId=409&familyId=1506&abstractName=spruer7c

  • in reply to Juan Gonzales
    Prodigy 130 points

    Yes, you are right about endpoint-type's dependence. But I need to use interrupt endpoint devices which are not share :-(.

  • in reply to VTR
    TI__Mastermind 37340 points

    are all 10 devices interrupt-type devices?  I think you can implement a software arbiter to manage the end-points; I do not know how difficult this would be though.

  • in reply to Juan Gonzales
    TI__Expert 7435 points

    We need to implement what is refered to as Interrupt Endoint Scheduling to work around the h/w endpoing limitation on DM6467 USB controller when acting as Host.  This is a significant functionality and one that needs to be profiles in customers environment for acceptance before it can be integrated into customers product flow.  The main reason being that the arbiter is implemented in software and hence is sensitive to timings and cpu loading.

    There might be patches in future that will implement this feature.  The schedule and timing is currently not determined.

     

    swami

  • in reply to swami
    Prodigy 130 points

    Hi, swami

    what is the status of your "Interrupt Endpoint Scheduler"? Is it commercial or free or for internal use only? What is the stage of development?

  • in reply to VTR
    TI__Expert 7435 points

    VT,

    The Interrupt Endpoint Scheduler will be available as part of the DM6467 maintanance release.  The timeline for the maintanance release is not finalized but I expect it to be between 1-2 months from now.  Pl. work with local TI FAE on the timelines of availability for more accurate time line.

    Another alternative would be to port this functionality from the existing DM644x patch (patch50) release stream to DM646x.  Most of the critical functionality would be the same between DM644x and DM646x w.r.t USB.

     

    swami

  • in reply to swami
    Prodigy 130 points
    swami,
     
    can you give some estimation for ARM 300 MHz loading with this scheduler? About 1% or 10% or 50%?
  • in reply to VTR
    TI__Expert 7435 points

    VT,

     In steady state we see a CPU loading between 5-10% with this feature enabled.

     

    swami