The USB bus reset is managed by hardware. It is initiated by a connected host.
When a USB reset is detected on the USB line, the following operations are performed by the controller:
- All endpoints are disabled, except the default control endpoint.
- The default control endpoint is reset (see Endpoint Reset for more details).
- The data toggle sequence of the default control endpoint is cleared.
- At the end of the reset process, the End of Reset (USBHS_DEVISR.EORST) bit is set.
- During a reset, the USBHS automatically switches to High-speed mode if the host is High-speed-capable (the reset is called High-speed reset). The user should observe the USBHS_SR.SPEED field to know the speed running at the end of the reset (USBHS_DEVISR.EORST = 1).