Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32n6/STM32N645/ETH/ETH_MACTSECNR#0x0
Timestamp Egress correction nanosecond register
Timestamp Egress Correction
https://github.com/modm-io/cmsis-svd-stm32