Fujitsu F2MC-16LX Hardware Manual page 299

[bit 0] CONF: Configuration detection bit
It displays the fact that the USB Function has been configured. The CONF bit is set when a SetConfig,
a USB command, has been successfully received. The CONF bit is an interrupt factor and writing "1" is
ignored. Please clear by writing "0". "1" is read at the read modification write.
CONF
0 SetConfig undetection and interruption clear factor
1 SetConfig is detected.
CHAPTER 13 USB FUNCTION
Operating mode
283