Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Renesas Electronics/R7FA6M3AH/SCI0/SISR#0x0
IICACKR=0
I2C Status Register
ACK Reception Data Flag
0 (0): ACK received
1 (1): NACK received
https://github.com/cmsis-svd/cmsis-svd-data