power supply for usb ports


just wondering what power supply is required to get all usb ports to
work on the bb xm. I want to connect a 2.5" hard disk drive and different usb-sticks.


You will need an external power supply of at least 3A. However, a 2.5" HDD can take more power than one port can supply depending on how old it is. You may need to use an external supply on the HDD. Each of the four ports can deliver 500mA, so that is 2A there and that leaves 1A to power the hub and the rest of the board with a buffer. The USB sticks won’t take much power.