wm8988 Wolfson Microelectronics plc, wm8988 Datasheet - Page 54

• Manufacturer Part Number: wm8988
• Description: Stereo Codec For Portable Audio Applications
• Manufacturer: Wolfson Microelectronics plc

WM8988
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OPERATION MODE
Stereo Headphone Playback
Stereo Line-in Record
Stereo Microphone Record
Mono Microphone Record
Stereo Line-in to Headphone Out
MINIMISING POP NOISE AT THE ANALOGUE OUTPUTS
POWER MANAGEMENT EXAMPLES
Table 45 Register Settings for Power Management
To minimize any pop or click noise when the system is powered up or down, the following procedures
are recommended.
POWER UP
•
•
•
•
•
POWER DOWN
•
•
•
Switch on power supplies. By default the WM8988 is in Standby Mode, the DAC is digitally
muted and the Audio Interface, Line outputs and Headphone outputs are all OFF (DACMU
= 1 Power Management registers 1 and 2 are all zeros).
Enable Vmid and VREF.
Enable DACs as required
Enable line and / or headphone output buffers as required.
Set DACMU = 0 to soft-un-mute the audio DACs.
Set DACMU = 1 to soft-mute the audio DACs.
Disable all output buffers.
Switch off the power supplies.
1
1
1
1
1
POWER MANAGEMENT (1)
0
1
1
1
1
PGL PGR ADL ADR
0
1
1
1
0
PGAs
0
1
1
0
0
0
1
1
1
0
ADCs
0
1
1
0
0
MBI
0
0
1
1
0
DAL DAR LO1
1
0
0
0
0
DACs
POWER MANAGEMENT (2)
1
0
0
0
0
1
0
0
0
1
Output Buffers
RO1
PD, Rev 4.0, October 2008
1
0
0
0
1
LO2
0
0
0
0
0
Production Data
RO2
0
0
0
0
0
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