I am considering using a mini-itx computer to do a lot of projects that use USB. I want to make sure that the USB device has enough bandwidth. For example, I have a data acquisition board that uses batch input, but these transmission frames have no guaranteed bandwidth. By putting it on a dedicated controller, I believe that 80-90% of the high-speed bandwidth is available because 10-20% is allocated for control endpoints. That is, in theory, I will have enough idle frames to support the bandwidth required by my circuit board.
But I'm looking at the block diagram of the USB ports returning to Intel processors, and I don't know how they are bundled together internally. ICH seems to include EHCI that supports high speed. How do I know if the data acquisition board shares the bus controller with other devices?
Najib 發表於 January 21, 2021
How much bandwidth do you want on your DA board?
Shadow 發表於 January 21, 2021
16 MB/s, I think HS USB is still very easy to achieve this bandwidth, but if other devices (such as cameras) are plugged in and take up all the bandwidth, the system is not reliable.
Darling 發表於 January 21, 2021
Starting from the 6th generation Intel processors (Skylake-Kaby Lake and some mobile SoCs such as Braswell), EHCI (traditional USB 2.0 controller) has been eliminated from Intel platforms. USB 2.0 services now use "native USB 2.0 support" entirely through the xHCI USB 3.x controller.
The improvement brought by the USB 2.0 support of xHCI is that the USB 2.0 HS (high-speed) bandwidth is no longer shared between root ports, so several devices with HS bandwidth requirements can coexist on the system without being exhausted and shared.
Therefore, as long as your device is connected to a USB root port instead of a USB hub, you don't have to worry about other devices taking up bandwidth.
Vivi 發表於 January 21, 2021
Yes, the hub has only a standard shared architecture.
