CPUC controls elements of the Arm®
Cortex®-M33
processor such as enabling floating-point exceptions. It is
also able to lock certain features of the CPU and prevent them from being modified.
CPUC can generate events and CPU interupts for exceptions in the floating point unit (FPU), as shown in the
following block diagram. Examples of such exceptions are divide-by-zero or floating-point
overflow.
Figure 1. Block diagram
CPUC holds a CPU identifier CPUID, used in the system to
uniquely identify the processing unit of a core.
In addition, CPUC holds a LOCK register, which is used to lock
certain CPU features and prevent them from being modified. One example is the
LOCK.LOCKSAU field. When set to Locked,
this prevents further modifications to the SAU registers.