Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series1/EFR32MG1B/EFR32MG1B232F256IM48/I2C0/TXDOUBLE#0x0
Transmit Buffer Double Data Register
TX Data
https://github.com/cmsis-svd/cmsis-svd-data