Access to the features can be restricted. A feature can be declared as secure so that only secure peripherals can access it.
The security attribute of a feature is configured by using corresponding SPU's feature register. When the secure attribute is set for a feature, only secure peripherals and code will be able to access that feature. For example, register FEATURE.GRTC.CC[n] is used to configure security for the capture-and-compare functionality of the GRTC peripheral. When the secure attribute is set, only secure code can access and use the corresponding capture-and-compare registers, tasks, and events.
See the SPU configuration to find the features supported by each SPU instance.