According to the specifications, USB 3. If you look at the datasheet of USB 3. This is verified in real life: we have observed identical performances for Full-Speed traffic routing on USB 2.
The only advantage in favor of USB 3. The only USB 2. The USB 2. Here is a summary table to conclude this UBS hub test bench. Note that our comparison is focused on the performance for handling multiple Yoctopuce devices.
We have not tested high-speed USB 3. We have also added at the end of the list our own Micro-USB-Hub-V2 for comparison purpose, even though it does not really belong to the same category since it is designed to be embedded rather than used stand-alone. At this price point, we can only hope that the workers who built it have received enough money to make a living. Alternatively, the ExSys hubs are both affordable and of good quality. Most of them feature an industrial V terminal connector for power supply.
Once we know how to connect many USB devices using hubs, we must still make sure that the host will be able to handle them all. First the CPU must be powerful enough to handle all traffic. But in addition, there are sometimes constraints in the USB controller itself which limit the maximum number of usable devices. Here is the results of our experiments.
On slightly older motherboards featuring several USB 2. Make sure not to get tricked by the fact that several USB ports may actually correspond to the same controller: you need to verify how devices are spread on controllers using the Device Manager.
With a bit of care, we have been able in this way to use about fifty devices on a single machine, each sending messages per second. The problem is that, by design, this controller cannot talk to more than about 20 USB 2. So if you have a mouse, a keyboard and a few hubs, you will not be able to use more than 13 to 15 Yoctopuce devices.
On the iMac that we have tested, we have been able to connect 30 devices, each sending messages per second, on each of the two USB 2. Over 10 devices, the handling of High-Speed devices seems to slow down exponentially, and it is even impossible to get 17 devices to work simultaneously, even when they send almost no data. It is impossible to connect more than 13 devices, as the USB controller does not have enough ressources.
However the Intel Edison is also capable of handling devices sending messages at 1 KHz, as long as you don't push to far: it is still a small machine And don't forget that your real-world tests are the only proof that your design works. We can give you hints at how to get the best results, but ultimately it is your hardware and your design that will make the difference.
What are "loose packets"? What kind of packets are attached to hubs and become loose on cheap ones. I thought packets consisted of data and not a physical part and therefore would never loosen. Remember that each hub chip itself contains a USB 2. Going back to the previous example of the commonly available Intel XHCI-based host system, the integrated controller supports a maximum of 96 endpoints.
By removing one device 23 total , we would drop down to 96 endpoints. However, many host machines use USB internally for built-in peripherals, including webcams, touchscreens, and touchpads. Therefore, the number of external devices that can be connected is different for every system. This number can be further impacted by a host machine where the USB connectors are already expanded by internal hubs.
We've created a follow-up blog post with a suggested topology to reach maximum daisy-chaining potential. Read it here. Unfortunately, this will limit all devices to USB 2. Use a USB 2. Discrete USB host controllers do not typically have this limitation.
Adding a discrete USB host controller in a PCIe expansion slot is a great way to expand the total tree and number of devices available. Thank you for this complete but clear explanation. So theoric limits of and devices for USB 2. Unless you could attach all devices in the first tier!
Cheers from France. It is technically possible to hit devices, but it is very very unlikely. Besides the tier limit, you also have the end point limit to contend with. Even worse, macOS has some other limitations which come into play when making a hackintosh. Adding a PCIe expansion card may allow for more end points.
At the least, an expansion card will not have all the built-in devices and hubbing that many computers come with. I also have USB hubs connected for various devices: printer, two external hard drives, webcam, camera, phone, iPod.
It means I can move the laptop by disconnecting the power and one USB cable. Is there a limit to what can be connected though one port? Tom Corcoran. A USB host can support up to devices in a "tiered star" formation, but you can run out of bandwidth if you use too many of them at once.
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