Datasheet

SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
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Interrupt handler
A program that control of the processor is passed to when an interrupt occurs.
Interrupt vector
One of a number of fixed addresses in low memory, or in high memory if high vectors are configured, that contains
the first instruction of the corresponding interrupt handler.
Little-endian (LE)
Byte ordering scheme in which bytes of increasing significance in a data word are stored at increasing addresses
in memory.
See also “Little-endian memory” , “Endianness”
Little-endian memory
Memory in which:
a byte or halfword at a word-aligned address is the least significant byte or halfword within the word at that address
a byte at a halfword-aligned address is the least significant byte within the halfword at that address.
Load/store architecture
A processor architecture where data-processing operations only operate on register contents, not directly on
memory contents.
Memory Protection Unit (MPU)
Hardware that controls access permissions to blocks of memory. An MPU does not perform any address
translation.
Prefetching
In pipelined processors, the process of fetching instructions from memory to fill up the pipeline before the
preceding instructions have finished executing. Prefetching an instruction does not mean that the instruction has to
be executed.
Read
Reads are defined as memory operations that have the semantics of a load. Reads include the Thumb instructions
LDM, LDR, LDRSH, LDRH, LDRSB, LDRB, and POP.
Region
A partition of memory space.
Reserved
A field in a control register or instruction format is reserved if the field is to be defined by the implementation, or
produces Unpredictable results if the contents of the field are not zero. These fields are reserved for use in future
extensions of the architecture or are implementation-specific. All reserved bits not used by the implementation
must be written as 0 and read as 0.
Should Be One (SBO)
Write as 1, or all 1s for bit fields, by software. Writing as 0 produces Unpredictable results.
Should Be Zero (SBZ)
Write as 0, or all 0s for bit fields, by software. Writing as 1 produces Unpredictable results.
Should Be Zero or Preserved (SBZP)
Write as 0, or all 0s for bit fields, by software, or preserved by writing the same value back that has been previously
read from the same field on the same processor.