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Chapter 7
Bus and Memory Control (BCU, MEMC)
Preliminary User’s Manual U17566EE1V2UM00
7.8.2
Access to 16-bit data busses
This section shows how byte, half word and word accesses are performed for a
16 bit data bus.
Access all data in order starting from the lower order side.
(1)
Byte access (8 bits)
(a) Little endian
Figure 7-33
Left: Access to even address (2n)
Right: Access odd address (2n + 1)
(b) Big endian
Figure 7-34
Left: Access to even address (2n)
Right: 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
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
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