Datasheet

239
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
12.11.2.2 MPU Control Register
Name: MPU_CTRL
Access: Read/Write
Reset: 0x00000800
The MPU CTRL register enables the MPU, enables the default memory map background region, and enables the use of the MPU
when in the hard fault, Non-maskable Interrupt (NMI), and FAULTMASK escalated handlers.
• PRIVDEFENA: Privileged Default Memory Map Enable
Enables privileged software access to the default memory map:
0: If the MPU is enabled, disables the 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 the use of the default memory map as a background region for privileged software accesses.
When enabled, the background region acts as a region number -1. Any region that is defined and enabled has priority over this
default map.
If the MPU is disabled, the processor ignores this bit.
• HFNMIENA: Hard Fault and NMI Enable
Enables the operation of MPU during hard fault, NMI, and FAULTMASK handlers.
When the MPU is enabled:
0: MPU is disabled during hard fault, NMI, and FAULTMASK handlers, regardless of the value of the ENABLE bit.
1: The MPU is enabled during hard fault, NMI, and FAULTMASK handlers.
When the MPU is disabled, if this bit is set to 1, the behavior is unpredictable.
• ENABLE: MPU Enable
Enables the MPU:
0: MPU disabled.
1: MPU enabled.
31 30 29 28 27 26 25 24
–
23 22 21 20 19 18 17 16
–
15 14 13 12 11 10 9 8
–
76543210
– PRIVDEFENA HFNMIENA ENABLE