CHAPTER 4 BUS CONTROL FUNCTION
89
User’s Manual U15195EJ5V0UD
(2) Halfword access (16 bits)
(a) When the bus width is 16 bits (little endian)
<1> Access to even address (2n)
<2> Access to odd address (2n + 1)
1st access
2nd access
7
0
7
0
Halfword
data
15
8
External
data bus
2n
Address
15
8
2n + 1
7
0
7
0
Halfword
data
15
8
15
8
External
data bus
2n + 1
Address
7
0
7
0
Halfword
data
15
8
15
8
External
data bus
2n + 2
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)
1st access
2nd access
1st access
2nd access
7
0
7
0
Halfword
data
15
8
External
data bus
Address
7
0
7
0
Halfword
data
15
8
External
data bus
2n + 1
Address
2n
7
0
7
0
Halfword
data
15
8
External
data bus
Address
7
0
7
0
Halfword
data
15
8
External
data bus
2n + 2
Address
2n + 1
Содержание PD703114
Страница 2: ...2 User s Manual U15195EJ5V0UD MEMO ...