I make a pcb with tusb2036 and two usb outs, like schematic:
the power supply is externall, so i put the /buspwr in low, like datasheet say, /ocprot and /overcur in high, for not overcurrent detection, mode in low, for crystal use.
but, if /buspwr in low, when i connetc the board in PC and put a pen driver - for example, in the usb port (CN7), the windows xp show me the message "usb power exceeded".
if i power off the circuit, put the /buspwr in high and power on, the circuit works.
i am wrong in my understanding? this pin should be put in low to work correctly?
i make another board with tusb2046 - see schematic 2046-1, this board works fine, with externall power supply too and pin /busspwr in low.
whay this difference between two hubs?
The functionality of the terminal BUSPWR is reversed between the TUSB2036 and the TUSB2046B.
On the TUSB2036 this terminal is active-low, so if you are using an external source for the device you should tie this terminal to 3.3V.
On the TUSB2046B this terminal is active-high, so if you are using an external source you should tie this terminal to ground.
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