After the SX2 has its descriptor information, it connects and enumerates. The external processor should wait for the ENUM_OK interrupt. The external processor can perform other tasks while waiting for enumeration to complete. After it gets the ENUM_OK interrupt, the external processor should write all of the SX2 configuration registers values it needs to set up the SX2 for its application. After enumeration, it's a good idea for the external processor to check and see whether the SX2 enumerated at high or full speed and adjust the EPxPKTLENH/L register so that the SX2 knows when to automatically send packets to the host. The last initialization task is for the external master to flush all of the SX2 FIFOs.