• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 99 subscribers
  • Views 282 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.

Using mutliple OMAP35xx USBhost ports at all speeds

Ted Michon
Prodigy 230 points

The USB User Guide alone is rather daunting for a newbie.

In addition to the HS OTG port, we would like to have 2 or 3 additional ports that are dynamically HS, FS, and LS. I note that the Beagle Board, Cogent Board, and Mistral Board all only support HS, telling the user to add a hub to get FS or LS. Are there any sample designs that get multiple speeds?

-Ted

  • 0
    TI__Mastermind 41665 points

    For the high speed host subsystem on the OMAP3 if one port is configured for high speed ULPI than all other ports must be configured the same (mentioned as a note in section 23.2.1 of the TRM), so my understanding is that in general users will want the HS support so the software configures for HS leading to the need for a hub for devices that require FS or LS. This being said, I believe if you want to use lower speeds directly you would have to have lower speeds only for all the host ports, and you would have to modify the existing host USB drivers to manage this, I am not sure that a dynamic speed switching design is possible, as I have never come across one.

  • 0 in reply to Bernie Thompson TI
    Prodigy 230 points

    Bernie-

    I was afraid of that. It would be bad to have to explain to our customers that the USB jacks provided work only at High Speed, but not at Full Speed or Low Speed. Internally, it's hard to explain that we bought a processor with 3 ports and hardware for all 3 speeds, but that none of them work at all 3 speeds and, in fact, that one cannot even have one port at each speed!

    But thanks for confirming what we feared.

    -Ted

     

  • 0 in reply to Ted Michon
    TI__Genius 9460 points

    Bernie/Ted,

    Limitation of all the three ports in either PHY or TLL mode is true for ES2.1 and earlier but for ES3.x we can have PHY/TLL mode on per port basis.

    Even with ES2.1 and earlier we can have one port is HS mode and at the same time other port in FS mode but both the ports have to operate in PHY mode or TLL mode.

    In ES3.x onward each port can individually be programmed in PHY mode or TLL mode and thus we can have something like,

                     * port-1 supporting HS and in PHY mode

                     * port-2 supporting FS and in TLL mode

    port-3 can't be configured in PHY mode.

     

    You can find some related linux-driver updates at,

    http://marc.info/?l=linux-omap&m=124956080820097&w=2

    http://marc.info/?l=linux-omap&m=124956054719677&w=2

    Regards,
    Ajay

  • 0 in reply to Ajay
    Prodigy 230 points

    Ajay-

    Thanks for making this clear. It's funny that on a device with 6x10+ pins allocated to 6 USB host ports needs yet another chip (hub) to get 1 ordinary 3-speed USB port, but that's what we will do.

    -Ted

  • 0 in reply to Ted Michon
    Mastermind 7560 points

    Hi Ajay-san,

    I've got the same  question on this from my customer.
    According to OMAP35xx Errata(SPRZ278F) below, a high speed USB hub is required as shown in Figure 15(page 125).

      ----------------------------------------------------------------------------------------------- 
      o OMAP35xx Silicon Errata [SPRA278F]

          - Page 122
             4.1.3  High-Speed USB Host Subsystem: Some Limitations Exist
                        When Connecting to External Devices
      ----------------------------------------------------------------------------------------------- 

    So, could you please let me know any reference designs, recommended HS USB hub devices, related the latest linux-drivers if you have any?

    Thanks in advance for your cooperation.

    Best regards,
    j-breeze