CM6571 Datasheet, PDF (45/63 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
Commands
9.3.2 scenario II
Mode_Sel pins control for demand to download firmware codes with power saving
When default DSP algorithm ROM codes could NOT satisfy your needs, CM6571 ENC chip allows baseband to download a
whole new version of codes into the RAM program through I2C interface. In this situation, we suggest you still use
Mode_Sel 0/1 pins to simply control chip operation mode for better power saving. However, to avoid downloading time
(1.16sec for 32Kbytes FW @ I2C fast mode) every time getting start from Power Down mode, it might be necessary to
use Suspend mode (Mode_Sel0=low, Mode_Sel1=high) for Phone Standby or Sleep status, which will keep the RAM
program/data alive. When phone is active during a call, switch to active ENC ON mode by baseband’s phone active
signal pin or a GPIO pin to pull-high Mode_Sel0 pin, and Mode_Sel1 pin must be pull low at the same time. Reverse back
to suspend when ending a call to Standby/Sleep status. The same as Scenario I, drive both Mode_Sel 0/1 pins to high at
the same time to enter By-Pass mode when you want to turn off ENC in a call. The phone status should match the
following operation modes:
Phone Status
Operation Mode
Mode_Sel0/1
Control
Power-Off/
Deep Sleep
Power Down (or
No power
supply)
Mode_Sel 0=0
Mode_Sel 1=0
Stand-By/Sleep Active (Effect On)
Suspend
Mode_Sel 0=0
Mode_Sel 1=1
Active
(ENC ON, or AEC or NR
by I2C command)
Mode_Sel 0=1
Mode_Sel 1=0
Active (Effect Off)
By-Pass
Mode_Sel 0=1
Mode_Sel 1=1
Revised: Nov. 2012
Page 45 / 63
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