Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series0/EZR32LG/EZR32LG330F128R69/USB/DIEP0TXFSTS#0x0
Device IN Endpoint 0 Transmit FIFO Status Register
TxFIFO Space Available
https://github.com/cmsis-svd/cmsis-svd-data