ASAHI KASEI
[AK8817/18]
Device Control Interface
The AK8817/18 is controlled via I2C Bus Control Interface.
[ I2C SLAVE Address ]
2C Slave Address is 0x40
[ I2C Control Sequence ]
(1) Write Sequence
When the Slave Address of the AK8817/18 Write mode is received at the first byte, Sub Address at the second byte and
Data at the third and succeeding bytes are received.
There are 2 operations in Write Sequence - a sequence to write at every single byte, and a sequential write operation to
write multiple bytes successively.
(a) 1 Byte Write Sequence
Slave
Address
8-bits
Sub
Address
8-bits
S
w
A
A
Data
A
Stp
1bit
1bit
8-bits
1bit
(b) Multiple Bytes ( m-bytes ) Write Sequence ( Sequential Write Operation )
Sub
Address
(n)
Slave
Address
Data(n+
1)
S
w
A
A
Data(n)
8-bits
A
A
Data(n+m)
8-bits
A
stp
….
8-bits
1bit
8-bits
1bit
1bit
8-bits
1bit
1bit
(2) Read Sequence
When the Slave Address of the AK8817/18 Read mode is received, Data at the second and succeeding bytes are
transmitted.
Sub
Slave
Slave
Address
S
w
A
Address
(n)
A
1
rS
R
A
1
Data1
8-bits
A
1
Data2
8-bits
A
1
Data3
8-bits
A
1
…
Data n
8-bits
Ā
stp
Address
8-bits
1
8-bits
8-bits
1
Abbreviated terms listed above mean :
S, rS : Start Condition
A
: Acknowledge ( SDA Low )
A-
stp
R/W
: Not Acknowledge ( SDA High )
: Stop Condition
1 : Read
0 : Write
:
:
to be controlled by the Master Device. Micro-computer interface is output normally .
to be controlled by the Slave Device. To be output by the AK8817/18.
Rev.001E
18
2009 / 12
AKM [ ASAHI KASEI MICROSYSTEMS ]
