2.2.3.4 USB_DEVICE_SOF_EVENT_ENABLE Macro
C
#define USB_DEVICE_SOF_EVENT_ENABLE
Summary
USB Device Layer SOF Event Enable
Specifying this configuration macro will cause the USB Device Layer to generate the USB_DEVICE_EVENT_SOF event. On Full Speed USB Devices, this event will be generated every 1 millisecond. On High Speed USB devices, this event will be generated every 125 microsecond.