ASAHI KASEI
[AK8817]
Device Control Interface
The AK8817 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 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
S
w
A
Address
8-bits
1bit
Sub
Address
8-bits
A
1bit
Data
8-bits
A
1bit
Stp
(b) Multiple Bytes ( m-bytes ) Write Sequence
( Sequential Write Operation )
Sub
Slave
Data(n+
S
w
A
Address
A
Data(n)
A
Address
1)
(n)
8-bits
1bit
8-bits
1bit
8-bits
1bit
8-bits
A
1bit
….
Data(n+m)
8-bits
A
1bit
stp
(2) Read Sequence
When the Slave Address of the AK8817 Read mode is received, Data at the second and succeeding bytes are
transmitted.
S
Slave
Address
w
A
Sub
Address
(n)
A
rS
Slave
Address
R
A
Data1
A
Data2
A
Data3
A
…
Data n
Ā
stp
8-bits
1
8-bits
1
8-bits
1
8-bits
1
8-bits
1
8-bits
1
8-bits
1
Abbreviated terms listed above mean :
S, rS
A
A-
stp
R/W
: Start Condition
: Acknowledge ( SDA Low )
: 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.
MS0413-E-03
13
2006 / 05
AKM [ ASAHI KASEI MICROSYSTEMS ]
