CM6206 Datasheet, PDF (21/35 Pages) C-Media Electronics – High Integrated USB Audio I/O Controller

CM6206
High Integrated USB Audio I/O Controller
Figure 6-3. IIC transaction example
The figure below shows typical transactions between MCU and CM6206. After a START, MCU should send
7-bit slave address (7’b0111000) first, and then the 8^th bit denotes a read transfer when it’s high; or a
write transfer when it’s low.
MCU write:
S
8’h70
MCU read:
S
8’h70
S
8’h71
0
8’h01
0
Byte[1]
0
Byte[2]
1P
0
8’h00
1
0
Byte[0]
0
Byte[1]
0
Byte[2]
0
Byte[3]
1P
From CM6206 to MCU
From MCU to CM6206
S
START condition
P
STOP condition
0
Positive acknowledge
1
Negative acknowledge
Byte
One byte data
In a write transfer, MCU keeps acting as the transmitter. CM6206 regards the first DATA byte as start
register address. The second and third DATA bytes are the content that MCU writes to the register
addresses.
In a read transfer, two transactions are necessary. MCU resets start register address by the first
transaction. Then MCU changes to be the receiver during the second transaction to get four bytes of data.
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