Use the MPU Control Register to enable and disable the MPU, and to control whether the default memory map is enabled as a background region for privileged accesses, and whether the MPU is enabled for HardFaults and NMIs.
| ENABLE | Enables the MPU. If the MPU is disabled, privileged and unprivileged accesses use the default memory map. 0 = MPU disabled. 1 = MPU enabled. |
| HFNMIENA | Controls the use of the MPU for HardFaults and NMIs. Setting this bit when ENABLE is clear results in UNPREDICTABLE behaviour. When the MPU is enabled: 0 = MPU is disabled during HardFault and NMI handlers, regardless of the value of the ENABLE bit. 1 = the MPU is enabled during HardFault and NMI handlers. |
| PRIVDEFENA | Controls whether the default memory map is enabled as a background region for privileged accesses. This bit is ignored when ENABLE is clear. 0 = If the MPU is enabled, disables use of the default memory map. Any memory access to a location not covered by any enabled region causes a fault. 1 = If the MPU is enabled, enables use of the default memory map as a background region for privileged software accesses. When enabled, the background region acts as if it is region number -1. Any region that is defined and enabled has priority over this default map. |