AK8963N Datasheet, PDF (24/38 Pages) Asahi Kasei Microsystems – 3-axis Electronic Compass

[AK8963]
7.2.2. WRITE Instruction
When the R/W bit is set to "0", AK8963 performs write operation.
In write operation, AK8963 generates an acknowledge after receiving a start condition and the first byte (slave
address) then receives the second byte. The second byte is used to specify the address of an internal control
register and is based on the MSB-first configuration.
MSB
A7
A6
A5
A4
A3
A2
Figure 7.7 Register Address
LSB
A1
A0
After receiving the second byte (register address), AK8963 generates an acknowledge then receives the third
byte.
The third and the following bytes represent control data. Control data consists of 8 bits and is based on the
MSB-first configuration. AK8963 generates an acknowledge after every byte is received. Data transfer always
stops with a stop condition generated by the master.
MSB
D7 D6
D5 D4 D3 D2
Figure 7.8 Control Data
LSB
D1 D0
AK8963 can write multiple bytes of data at a time.
After reception of the third byte (control data), AK8963 generates an acknowledge then receives the next data.
If additional data is received instead of a stop condition after receiving one byte of data, the address counter
inside the LSI chip is automatically incremented and the data is written at the next address.
The address is incremented from 00H to 0CH or from 10H to12H. When the address is in 00H~0CH, the
address goes back to 00H after 0CH. When the address is in 10H~12H, the address goes back to 10H after 12H.
Actual data is written only to Read/Write registers (refer to 8.2).
SDA
S
T
A
R/W="0"
R
T
S
Slave
Address
Register
Address(n)
Data(n)
Data(n+1)
A
A
A
A
C
C
C
C
K
K
K
K
Figure 7.9 WRITE Instruction
S
T
O
P
Data(n+x)
P
A
A
C
C
K
K
MS1356-E-02
- 24 -
2013/10