Hi, it'Andrea Orazzini from CAEN SpA (Viareggio, Italy). I have designed an hub USB using the TUSB4020BI. I need to connect to the hub a mouse and a keyboard. However it seems that the hub works only if the boad is powerd with at least one device attached. If I power the boad with no device connected or if I disconnect both devices during the operation, I can't reconnect the mouse and the keybord.
I have tried in two configuration mode:
1) PIN 32 SMBUSz not connected and no I2C communication;
2) PIN 32 SMBUSz tied to GND with 4.7K Ohm resistor. In this case I send via I2C 0x83h to the configuration register (7h) and then clear the cfgActive bit of the Device Status an Command Register (F8h).
In both case I have the same results. If I have no device connected to the hub, I can't connect anything.
Can you give me some suggestion?
Kind regards,
Andrea Orazzini