Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Renesas Electronics/R7FA6M3AH/IIC1/SARU2#0x0
FS=0
Slave Address Register U2
7-Bit/10-Bit Address Format Selection
0 (0): The 7-bit address format is selected.
1 (1): The 10-bit address format is selected.
10-Bit Address(bit8)
10-Bit Address(bit9)
https://github.com/cmsis-svd/cmsis-svd-data