State of TetraHub PWR# pins

Question: What is the state of the PWR# pins when the hub is in a disconnected state from the host (BUSPOWER pin low) and the hub being a self powered device, is still in a powered state?  Are these output pins still driven low or are they floating?

 

Answer:

On power-up, the PWR# pins will be driven by the TetraHub, but to unknown states. If the hub sees a bus reset upstream (when plugged into the host), then the hub controller itself will be reset and the PWR# lines will be driven high. Now, if it is disconnected (but the hub is still in a powered state) it will will remain in the previous state (whatever it was at before being unplugged).