CM6571 Datasheet, PDF (46/63 Pages) C-Media Electronics – USB 2.0 full speed-compliant

CM6571
USB Audio Sound Chip
Baseband or
Application
Processor
GPIO0 / Active High Mode_Sel 0
GPIO1
Mode_Sel 1
CM6571
ENC Processor
I2C Master_CLK
I2C Slave_CLK
I2C Master_DAT
I2C Slave_DAT
Downloading FW
9.3.3 scenario III
I2C control only for convenience
CM6571 ENC chip also allows baseband to switch the operation modes via I2C programming hardware registers if
customers do not want to use additional GPIO control. This way only uses I2C for all control over ENC chip but will need
higher power levels to keep I2C slave interface and digital core alive in Standby status. In this situation, we suggest to
keep Power Down (00) or Suspend (10) mode for Phone Standby status (in this I2C control scenario, two modes are
actually the same operation), which will keep the RAM program/data and I2C alive. Therefore, baseband does not need
to program or download codes every time when phone is going to Active status for calling. Set registers [1:0] to 01 for
ENC ON operation in active normal handset calling. Reverse back to Power Down/Suspend mode when ending a call to
Standby/Sleep status. The same with Scenario I and II, set register [1:0] as 11 to enter By-Pass mode when the user (or
design) would like to turn off ENC in a call or other applications. The phone status should match the following
operation modes via I2C interface writing from the baseband:
Phone Status
Operation Mode
Mode_Sel0/1
Control
Power-Off
Power Down (No
power supply)
Mode_Sel 0=0
Mode_Sel 1=0
Stand-By/Sleep/
Deep Sleep
Active (Effect On)
Power Down or
Suspend
Active
(ENC ON, or AEC or NR
by I2C command)
Mode_Sel 0=0
Mode_Sel 0=1
Mode_Sel 1=0 or 1
Mode_Sel 1=0
Active (Effect Off)
By-Pass
Mode_Sel 0=1
Mode_Sel 1=1
Baseband or
Application
Processor
I2C Master_CLK
I2C Slave_CLK
CM6571
ENC Processor
I2C Master_DAT
I2C Slave_DAT
Mode Selection
/Commands
/Downloading FW
Revised: Nov. 2012
Page 46 / 63
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