jetson tx2 power_on

HI,
I have a question relevant to VDD_5V0_IO_SYS. Is this voltage need if the jetson is not yet started?
I read that there is a pull-up to VDD_5V0_IO_SYS but I do net see it in my adapter, I start to furnish the 5V when CARR_PWON is set only, than there is no voltage on PWR_BTN. Have I produce this voltage before? and if yes where I have to apply to jetson module?

thank you
maurizio

Is this still about usb issue in other topic? Please list in same topic then. VDD_5V0_IO_SYS is one of rails of carrier board, it will power up after module power on, you can see the power sequence in OEM DG, that should be followed well.