Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Infineon/XMC4300/ECAT0/MII_ECAT_ACS_STATE#0x0
EN_ACS_MII_BY_PDI=value1
MII ECAT ACS STATE
Access to MII management
0 (value1): ECAT enables PDI takeover of MII management control
1 (value2): ECAT claims exclusive access to MII management
https://github.com/cmsis-svd/cmsis-svd-data