Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Infineon/XMC4300/ECAT0_FMMU0/FMMU_P_START_BIT#0x0
Ph0sical Start bit FMMU y
Physical starting bit as target of logical start bit mapping
https://github.com/cmsis-svd/cmsis-svd-data