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TUSB8041: TUSB8041 bandwidth

Yangbo
Intellectual 1690 points
Part Number: TUSB8041

Hi team,

My customer is using TUSB8041, he has two questions about the bandwidth as below:

  1. Assuming the USB bandwidth is 5Gpbs, then what is the bandwidth of P1,P2,P3 and P4? What is the bandwidth of P1 and P2 when P3 and P4 are not being used?


2. When connecting another USB hub to P1, what is the bandwidth? What should we pay attention to when doing this?


Thanks a lot!

Yangbo

  • 0
    TI__Guru 64326 points
    Yangbo,

    TUSB8041 acts as a USB slave device so the overall bandwidth is determined by the host controller. USB Hubs are transparent to the host and the host allocates the appropriate bandwidth to each port. In addition the bandwidth or overall throughput on each port is determined by a combination of the host controller and the speed at which the USB device on a port is ready to send data. This applies in both case one and case two.

    In the second case both USB Hubs are transparent to the host and will allocate the resources appropriately. However, both USB 2.0 and USB 3.0 data lines must be connect on P1 to the TUSB8041 so that USB 2.0 and USB 3.0 devices can be supported on P5 - P8.

    USB High/Full/Low speed (USB2.0) and USB Super speed (USB 3.0) occupy different wires so the bandwidth allocation on the USB 2.0 lines will not affect the bandwidth allocation on the USB 3.0 lines.
  • 0 in reply to Malik Barton57
    TI__Intellectual 1690 points
    Hi, what do you mean by "In addition the bandwidth or overall throughput on each port is determined by a combination of the host controller and the speed at which the USB device on a port is ready to send data"? Can you give me an example?
  • 0 in reply to Yangbo
    TI__Guru 64326 points

    Yangbo,

    The host controller will dictate the speed at which data is sen, up to 5 Gbps for USB 3.0, but if a slow device tells the host that it is ready for data communication every 10's of seconds then the overall data throughput from source to sink is diminished even though the speed which data is sent at is fast.