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USB ports speed

fred50021
Prodigy 60 points
Other Parts Discussed in Thread: AM3505

hi,

i am confused about the USB port speeds in the datasheets.

It seams port0 ist the most comfortabel one to use.

Can i use port0 as HS (480Mbps) host port for connecting USB Memory Sticks?

 

thanks

fred

  • 0
    TI__Intellectual 2655 points

    Can you pls confirm if you are using AM35x device? if so Yes you can use USB Port0 for HS mode of operation.

    Port0 is an OTG controller complient with 2.0 specs. hence you can use this port in both either in Host or device mode. Hence this port can be used for connecting to memory sticks, This port has a integrated PHY hence you won;t need additional HW for implementation

    other ports in the device are Host only Ports, we have ULPI lines coming out of device & you would need to use external PHY, but with these ports as well  you can use HS mode. you can still use these ports to connect with USB memory stick as you would be operating AM35x in Host mode.

     

    Hope this helps.

     

    Regards,

    Vaibhav Desai

     

  • 0 in reply to vaibhav
    Prodigy 60 points

    yes, it's an AM3505.

    I am still concerned about the comment "...high-speed limited host mode operations" mentioned in the technical manual on page 2244.

    What are the limitations if i use it in pure host mode compared to the other host ports?

    regards

    ferd

     

  • 0 in reply to fred50021
    TI__Guru 62855 points

    Before the USB Implementers Forum (USB-IF) released the OTG supplement, the only USB host officially recognized by them was a PC or MAC.  The USB-IF definition of a USB host allowed a user to load a software driver that would allow operation of any USB peripheral.    However, there were many products being developed that needed to operate as a USB host and they were not capable of meeting the USB-IF definition of a USB host.  Most of these products were using embedded processors running a Linux/VxWorks/WinCE type operating system which only supported very specific software drivers. A couple of  product examples: a DSL modem which provided a USB host port to operate as a print server, a set-top box which provided a USB host port to load firmware upgrades.  Since the USB host port on these example products did not meet the USB-IF definition of a USB host, there became known as limited hosts.

    The OTG supplement was the first official USB-IF recognition of a USB host which allowed limited host functions.

    Therefore the terminology “high-speed limited host mode operations” is referring to this type of product which does not meet the original definition of a USB host.