7.2. Memory types

The ARM architecture defines a set of memory types with characteristics that are suited to particular devices. There are three mutually exclusive memory type attributes:

MPU memory regions can each be assigned a memory type attribute. Table 7.2 shows a summary of the memory types.

Table 7.2. Memory attributes summary

Memory type attributeShared or Non-sharedDescription
Strongly Ordered-All memory accesses to Strongly Ordered memory occur in program order. All Strongly Ordered accesses are assumed to be shared.
DeviceSharedFor memory-mapped peripherals that several processors share.
 Non-sharedFor memory-mapped peripherals that only a single processor uses.
NormalSharedFor normal memory that is shared between several processors.
 Non-sharedFor normal memory that only a single processor uses.


The processor’s L1 cache does not cache shared normal regions.

For more information on memory attributes and types, memory barriers, and ordering requirements for memory accesses, see the ARM Architecture Reference Manual.

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