CHAPTER 4 BUS CONTROL FUNCTION
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User’s Manual U15195EJ5V0UD
4.5.3 Bus width
The V850E/IA2 accesses on-chip peripheral I/O and external memory in 8-bit, 16-bit, or 32-bit units. The following
shows the operation for each type of access. Access all data in order starting from the lower side.
(1) Byte access (8 bits)
(a) When the data bus width is 16 bits (little endian)
<1> Access to even address (2n)
<2> Access to odd address (2n + 1)
7
0
7
0
Byte data
15
8
External
data bus
2n
Address
7
0
7
0
Byte data
15
8
External
data bus
2n + 1
Address
(b) When the data bus width is 8 bits (little endian)
<1> Access to even address (2n)
<2> Access to odd address (2n + 1)
7
0
7
0
Byte data
External
data bus
2n
Address
7
0
7
0
Byte data
External
data bus
2n + 1
Address
Содержание PD703114
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