1. What is the max number of ports available
on an usb hub? Is it more than 7 ? if so
please provide us the information on it i.e., manufacturer etc…
2. Can we cascade usb hubs? If we can, how is the
addressing handled to the device from the host? Does it induces any delay?
TI offers a variety of FS/LS hubs like TUSB2036, TUSB2046B, TUSB2077 and also a SS hub like the TUSB8040.
You can cascade the TI hubs up to 5 tiers (below is a reference picture with two tiers of hub) just take in mind the power requirements, for example, a bus-powered hub can only support self-powered hubs on its downstream ports.
The maximum propagation delay for a hub is 70ns for Full-speed hubs and 300ns for low-speed hubs.
When a device is connected to one of the hub's downstream ports, the HUB "tells" the host that there is a new device on its Port #2 (for example) and so the host starts the enumeration process with that specific device.
You can find more information in the following link http://www.ti.com/lit/an/slla314/slla314.pdf
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.