CHAPTER 4 BUS CONTROL FUNCTION
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User’s Manual U14492EJ3V0UD
4.5.4 Bus width
The V850E/IA1 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 V850E/IA1 mPD703116
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