Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/NXP Semiconductors/NeoM3/ETHERNET/POWERDOWN#0x0
Power-down register.
Unused
PowerDownMACAHB. If true, all AHB accesses will return a read/write error, except accesses to the Power-Down register.
https://github.com/cmsis-svd/cmsis-svd-data