ASAHI KASEI
[AK2572]
9.3 Read / Write Operation
9.3.1 Byte Write
Byte Write operation is shown in Figure 9-2. Select address and then input the data to be written.
Figure 9-2 Byte Write
1 0 1 0
0 0
0
0
SDA
S
T
A
R
T
S
T
O
P
Device
Device
A
C
K
Address
A
C
K
Data
A
C
K
R/
W
Address-1
Address-2
(MSB First)
(MSB First)
9.3.2 Page Write
Page Write operation is shown in Figure 9-3. Up to 16 bytes of data can be written at one time. In Page Write
operation, the lower 4 bits of the 8 bits address are effective and the upper 4 bits data does not change.
Therefore after writing data at “xxxx 1111”, next address to be written is “xxxx 0000”.
Figure 9-3 Page Write
. . . .
1 0 1 0
0 0
0
0
0
0
0
SDA
Device Device
Address-1
Address
(MSB First)
A
C
K
S
T
A
R
T
R/ A
W C
K
Data (Address)
A
C
K
Data (Address + 1)
A
C
K
A
C
K
A S
C T
K O
P
Data (Address + n)
Address
-2
9.3.3 Current Address Read
Current Address Read operation is shown in Figure 9-4. Address location where data is to be read out is “most
recently accessed address + 1”.
Figure 9-4 Current Address Read
SDA
1 0 1 0
1 0
1
S
T
O
P
S
T
A
R
T
N
O
A
C
K
Device
Device
A
C
K
Data
R/
W
Address-1
Address-2
(MSB First)
9.3.4 Random Read
Random Read operation is shown in Figure 9-5. When to execute Random Read operation, assign an address
to be read out by Dummy Write operation, and issue a Read instruction.
Figure 9-5 Random Read
SDA
1 0 1 0
0 0
0
1 0 1 0
1 0
1
*
A
C
K
A
C
K
A
C
K
R/
W
S
T
O
P
S
T
A
R
T
Device
Address-1 Address-2
Device R/
Address
(MSB First)
S
T
A
R
T
Device
Address-1 Address-2
Device
Data
(MSB First)
N
O
A
C
K
W
*: Don't care when Write Protect "ON"
Dummy Write
-36-
< MS0290-E-01>
2004/8
AKM [ ASAHI KASEI MICROSYSTEMS ]
