CM6308 C-Media Electronics, Inc., CM6308 Datasheet - Page 21

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

Date: 09/04/2007
The figure below gives a complete picture of a typical transaction between the MCU and
CM6308. After a START, the MCU should send a 7-bit slave address (7’b0111000) first, and
then the 8th bit denotes a read transfer when it’s high; or a write transfer when it’s low.
During a write transfer, the MCU continues acting as the transmitter. The CM6308 regards the
first DATA byte as the start register address. The following DATA bytes are the content of the
registers that the MCU requests. In a read transfer, two transactions are necessary. The MCU
resets the start register address by the first transaction, then direction changes to get N of
data..
MCU write:
MCU read:
S
S
S
0x70
0x70
0x71
Byte N
S
0
0
0
0
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
21/42 -
…..
P
1
0
0
From MCU to CM6308
Negative acknowledge
STOP condition
Byte N
…..
Audio and Voice Applications
Single-Chip USB Solution for
0
1
Byte N
P
0
P
CM6308
Version: