EP_FAST=LP, FRAME=LP
USB Device Interrupt Priority
| FRAME | Frame interrupt routing 0 (LP): FRAME interrupt is routed to USB_INT_REQ_LP. 1 (HP): FRAME interrupt is routed to USB_INT_REQ_HP. |
| EP_FAST | Fast endpoint interrupt routing 0 (LP): EP_FAST interrupt is routed to USB_INT_REQ_LP. 1 (HP): EP_FAST interrupt is routed to USB_INT_REQ_HP. |
| RESERVED | Reserved. Read value is undefined, only zero should be written. |