WM8351 Datasheet, PDF (62/330 Pages) Wolfson Microelectronics plc – Wolfson AudioPlus™ Stereo CODEC with Power Management

WM8351
Production Data
13.3 ENABLING THE AUDIO CODEC
Before the audio CODEC can be used, it must be enabled by writing to the CODEC_ENA,
SYSCLK_ENA and BIAS_ENA register bits.
ADDRESS BIT
LABEL
R12 (0Ch) 12 CODEC_ENA
Power
Mgmt 5
DEFAULT
0
R11 (0Bh) 14 SYSCLK_ENA
0
Power
Mgmt 4
R8 (08h)
5 BIAS_ENA
0
Power
Mgmt 1
Table 19 Enabling the Audio CODEC
DESCRIPTION
Master codec enable bit. Until this bit is set, all
codec registers are held in reset.
0 = All codec registers held in reset
1 = Codec registers operate normally.
CODEC SYSCLK enable
0 = disabled
1 = enabled
Enables bias to analogue audio CODEC
circuitry
0 = disabled
1 = enabled
Each individual part of the audio CODEC (e.g. left/right ADC, left/right DAC, each analogue output
pin, mic bias etc.) also has its own enable bit, which must be set before that part of the CODEC can
be used. These enable bits are described in the sections that follow.
In order to minimize output pop and click noise, it is recommended that the WM8351 device is
powered up and down under control using the following sequences:
Power Up:
1. Ensure the CODEC power supplies are available before the CODEC is enabled
R12[CODEC_ENA]=1 . The order in which this is done should be DCVDD, DBVDD then
HPAVVD And/Or AVDD
2. Mute all outputs
3. Enable the anti-pop circuits by setting ANTI_POP. There are three Anti-pop setting options.
Recommended value is ANTI_POP = 01.
4. Ensure external capacitors are full discharged on all outputs that are used by delaying 250ms
5. Set the mixers and DAC volume to required settings
6. Enable VMID by setting VMID_ENA = 1. VMID should raise in a controlled fashion and charge
the output capacitors
7. Wait approx 500ms to allow VMID to charge.
8. Disable the anti-pop circuits by setting ANTI_POP = 00.
9. Un-mute all outputs
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PD, April 2012, Rev 4.5
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