Texas Instruments Development Kit for TM4C129x,Tiva™ ARM® Cortex™ -M4 Microcontroller DK-TM4C129X DK-TM4C129X 데이터 시트
제품 코드
DK-TM4C129X
■ The alias word at 0x2200.0000 maps to bit 0 of the bit-band byte at 0x2000.0000:
0x2200.0000 = 0x2200.0000 + (0*32) + (0*4)
■ The alias word at 0x2200.001C maps to bit 7 of the bit-band byte at 0x2000.0000:
0x2200.001C = 0x2200.0000+ (0*32) + (7*4)
Figure 2-4. Bit-Band Mapping
0x23FF.FFE4
0x2200.0004
0x23FF.FFE0
0x23FF.FFE8
0x23FF.FFEC
0x23FF.FFF0
0x23FF.FFF4
0x23FF.FFF8
0x23FF.FFFC
0x2200.0000
0x2200.0014
0x2200.0018
0x2200.001C
0x2200.0008
0x2200.0010
0x2200.000C
32-MB Alias Region
0
7
0
0
7
0x2000.0000
0x2000.0001
0x2000.0002
0x2000.0003
6
5
4
3
2
1
0
7
6
5
4
3
2
1
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0x200F.FFFC
0x200F.FFFD
0x200F.FFFE
0x200F.FFFF
1-MB SRAM Bit-Band Region
2.4.5.1
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 writes a 1 to the bit-band bit, and writing a
value with bit 0 clear writes a 0 to the bit-band bit.
bit in the bit-band region. Writing a value with bit 0 set writes a 1 to the bit-band bit, and writing a
value with bit 0 clear 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.
writing 0xFF. Writing 0x00 has the same effect as writing 0x0E.
When reading a word in the alias region, 0x0000.0000 indicates that the targeted bit in the bit-band
region is clear and 0x0000.0001 indicates that the targeted bit in the bit-band region is set.
region is clear and 0x0000.0001 indicates that the targeted bit in the bit-band region is set.
2.4.5.2
Directly Accessing a Bit-Band Region
“Behavior of Memory Accesses” on page 116 describes the behavior of direct byte, halfword, or word
accesses to the bit-band regions.
accesses to the bit-band regions.
2.4.6
Data Storage
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. Data
is stored in little-endian format, with the least-significant byte (lsbyte) of a word stored at the
For example, bytes 0-3 hold the first stored word, and bytes 4-7 hold the second stored word. Data
is stored in little-endian format, with the least-significant byte (lsbyte) of a word stored at the
December 13, 2013
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Texas Instruments-Advance Information
The Cortex-M4F Processor