acronyms and abbreviations from stm doc UM1734

CDC Communication Device Class
DFU Device Firmware Upgrade
FS Full Speed (12 Mbps)
HID Human Interface Device
Mbps Megabit per second
MSC Mass Storage Class
OTG On-The-Go: An OTG peripheral can switch HOST/DEVICE role on the fly
PID USB Product Identifier
SCSI Small Computer System Interface
SOF Start Of Frame
VID USB Vendor Identifier
USB Universal Serial Bus