38.6.2.2 Power-On and Reset

The following figure describes the USBHS Device mode main states.

After a hardware reset, the USBHS Device mode is in Reset state. In this state:

• the USBHS clock is stopped to minimize power consumption (USBHS_CTRL.FRZCLK = 1),
• the internal registers of the Device mode are reset,
• the endpoint banks are de-allocated,
• neither D+ nor D- is pulled up (USBHS_DEVCTRL.DETACH = 1).

D+ or D- is pulled up according to the selected speed as soon as the USBHS_DEVCTRL.DETACH bit is written to zero. See “Device Mode” for further details.

When the USBHS is enabled (USBHS_CTRL.USBE = 1) in Device mode (USBHS_CTRL.UIMOD = 1), its Device mode state enters Idle state with minimal power consumption. This does not require the USB clock to be activated.

The USBHS Device mode can be disabled and reset at any time by disabling the USBHS (by writing a zero to USBHS_CTRL.USBE) or when the Host mode is enabled (USBHS_CTRL.UIMOD = 0).