The SoftDevice requires certain hardware peripherals to function correctly.
When the SoftDevice is disabled, all hardware peripherals are available to the application. The hardware peripherals that must not be accessed directly by the application when the SoftDevice is enabled are defined in SoftDevice Controller integration notes and Multiprotocol Service Layer integration notes.
When the SoftDevice is enabled, those hardware peripherals shall be accessed only through the SoftDevice API. Through this API, the application has limited access. The S145 SoftDevice does not prevent the application from accessing the peripherals directly. Doing so leads to undefined behavior.