CM6308 C-Media Electronics, Inc., CM6308 Datasheet - Page 20

• Manufacturer Part Number: CM6308
• Description: Cm6308 Usb Audio Chip Specification
• Manufacturer: C-Media Electronics, Inc.

Date: 09/04/2007
0x70 is the slave address of CM6308, and it also tells CM6308 that it’s receiving a write
command. CM6308 regards the first coming DATA byte as the register address. The second
DATA byte is the DATA content that MCU writes at the register address. CM6308 will
auto-increment the register address to the next register address for the following writes DATA.
The figure below shows an example of read transfer. The MCU read command can not set the
register address, so the MCU may use a write command to set the register address first and
then start the read command. Because the CM6308 auto-increments the register address, the
second DATA byte will be the register data on the next address.
MCU write:
MCU read:
S
S
S
0x70
0x70
0x71
Byte N
Byte n
S
S
0
0
0
0
0
From CM6308 to MCU
START condition
Positive acknowledge
One byte data
From CM6308 to MCU
START condition
Positive acknowledge
One byte data
Byte 0
addr
addr
0
0
0
Byte 0
Byte 1
0
0
-
Byte 1
20/42 -
…..
P
P
1
1
0
0
From MCU to CM6308
Negative acknowledge
From MCU to CM6308
Negative acknowledge
STOP condition
STOP condition
Byte N
….
Audio and Voice Applications
Single-Chip USB Solution for
0
1
Byte N
P
0
P
CM6308
Version: