Datasheet
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
68
Figure 10-2. Bit-band mapping
10.5.5.1 Directly accessing an alias region
Writing to a word in the alias region updates a single bit in the bit-band region.
Bit[0] of the value written to a word in the alias region determines the value written to the targeted bit in the bit-
band region. Writing a value with bit[0] set to 1 writes a 1 to the bit-band bit, and writing a value with bit[0] set to 0
writes a 0 to the bit-band bit.
Bits[31:1] of the alias word have no effect on the bit-band bit. Writing
0x01
has the same effect as writing
0xFF
.
Writing
0x00
has the same effect as writing
0x0E
.
Reading a word in the alias region:
0x00000000
indicates that the targeted bit in the bit-band region is set to zero
0x00000001
indicates that the targeted bit in the bit-band region is set to 1
10.5.5.2 Directly accessing a bit-band region
“Behavior of memory accesses” on page 64 describes the behavior of direct byte, halfword, or word accesses to
the bit-band regions.
10.5.6 Memory endianness
The processor views memory as a linear collection of bytes numbered in ascending order from zero. For example,
bytes 0-3 hold the first stored word, and bytes 4-7 hold the second stored word. or “Little-endian format” describes
how words of data are stored in memory.
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