Usb devices how many

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. Welcome to the real world :- if a poorly designed USB hub accepts more USB packets than it can handle, it will just drop some of them. Looking into designing or ordering some USB hub to embed it to my network appliance.

If you'd have to get somewhere embeddable 4x, 7x or 24 port USB hub or design it by yourself, what chipset you'd choose for that task?

Never had to complain about it. Fantastic article, but I'm wondering how much of this still applies in ? In particular I'm wondering about limits on the newer Raspberry Pi 4, and also I have been reading people on various forums saying that with usb 3.

Is that true? The problem of split transactions to handle remains the same in How many USB devices can you connect? USB hub comparison Our first test is designed to observe how various USB hubs react to a small number of devices configured to send data at high frequency.

From this test, we can immediately distinguish between two groups of USB hubs: Those who loose packets, and happen to be mostly cheap ones purchased from retail outlet; Those who don't loose packets, and have usually been a bit more expensive A USB bus is not expected to loose packets: USB is supposed to provide a lossless transport layer. Reported In shows products that are verified to work for the solution described in this article.

This solution might also apply to other similar products or applications. Operating System Windows. Please disconnect alternate USB device currently not being used or connect one of the devices to a different port. If the number of endpoints connected exceeds the number supported by the USB host controller on your computer, Windows will throw an error indicating that the controller does not have sufficient resources for the device.

Try the following steps to resolve the error: Unplug any USB devices that are not necessary for your application. I have a Kensington dock with video for my Dell Inspiron laptop. I have a monitor, keyboard, mouse and external sound system connected to the dock. 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?