TUSB4020BI: LS on upstream port

Steve Widener

Part Number: TUSB4020BI

I am wondering if any USB 2.0 hubs exist that can do LS, FS and HS on the upstream port. I see many, including the 4020, do LS on the downstream, but not on the upstream.

over 3 years ago

+1 JMMN over 3 years ago

TI__Guru 60870 points

Hi Steve,

The USB specification does not allow for LS connection on the upstream port of a hub. Any HS capable USB 2.0 hub (like the TUSB4020B) can support HS or FS connection on its upstream port but the speed is determined by the downstream port to which it is connected. HS capable USB 2.0 hubs use transaction translators to translate between the high speed connection on the upstream port and any full speed or low speed device connected to its downstream ports.

Regards,

JMMN