CM6571 Datasheet, PDF (41/63 Pages) C-Media Electronics – USB 2.0 full speed-compliant

CM6571
USB Audio Sound Chip
9 DSP function description
9.1 Operation modes
It basically supports four operation modes with different power management levels for easy operating control: Power
Down/ENC ON/By-Pass/Suspend. It could be controlled by 2 HW mode_selector input pins (MSEL_0,MSEL_1) under
default setting, or by I2C command control set from the host controller/baseband. When I2C is chosen to switch these
modes, the DSP receives the mode switch command from Baseband chip through I2C interface and writes the result to
the two-bit mode_sel registers to handle the mode/power control. If baseband chip choose I2C interface to control the
mode selection, then some function blocks will be kept alive at Suspend and Power Down modes.
9.1.1 there are two bits for mode selection:
Mode_Sel Pins [1:0]
Register[1:0]
Mode
Description
00
Power Down (default)
Default state for power saving in phone’s Standby, Sleep,
Deep Sleep, or Power-off states
Chip and voice processor is turned on for phone active
01
Active (ENC/AEC/NR ON)
state (calling) (ENC is the default function, host CPU could
switch the function to AEC or NR for different applications
via I2C commands)
By-pass voice processor and redirect Mic-In signals to
11
By-Pass
Mic-Out directly (An option allowing users to turn off
ENC/AEC/NR functions during the call or other
applications)
Reserved alternative Suspend mode in phone’s Standby or
10
Suspend
Sleep states especially for keeping new downloaded F/W
codes in the internal RAM saving the reloading time for ENC
ON
Revised: Nov. 2012
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