CM6571 Datasheet, PDF (33/63 Pages) C-Media Electronics – USB 2.0 full speed-compliant

8.5 I2C interface
8.5.1 I2C master mode
8.5.1.1 I2C protocol timing
Write Transaction
CM6571
USB Audio Sound Chip
Slave Address 0 A
Map Address
A
Data0
A
Data1
A
Read Transaction
Slave Address 0 A
Map Address
A
Slave Address 1 A
Data0
A
From Master to Slave
From Slave to Master
SCL
1. N Byte Write Transaction
SDA
Slave Address 0 A
MAP
2. N Byte Read Transaction
SDA
Slave Address 1 A
Data 1
A
Data 1
A Data
Data ^A
Stop
A
Data
Data A
Stop
SCL
3. Auto Read Transaction (= Write- MAP- Only + N Byte Read Transaction)
SDA
Slave Address 0 A
MAP
A
Slave Address 1 A Data Data
Start
Stop Start
A
Stop
from master to slave
from slave to master
A  acknowledge ( SDA Low)
A  not acknowledge ( SDA High)
MAP: Memory Address Pointer
(the target register address
in slave device )
Revised: Nov. 2012
Page 33 / 63
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