WM8904
Pre-Production
MICBIAS CURRENT DETECT ...................................................................................................................................... 43
MICBIAS CURRENT DETECT FILTERING .................................................................................................................. 44
MICROPHONE HOOK SWITCH DETECTION .............................................................................................................. 46
DIGITAL MICROPHONE INTERFACE .......................................................................... 47
ANALOGUE-TO-DIGITAL CONVERTER (ADC) ........................................................... 49
ADC DIGITAL VOLUME CONTROL .............................................................................................................................. 49
HIGH PASS FILTER ...................................................................................................................................................... 51
ADC OVERSAMPLING RATIO (OSR) .......................................................................................................................... 52
DYNAMIC RANGE CONTROL (DRC) ........................................................................... 53
COMPRESSION/LIMITING CAPABILITIES .................................................................................................................. 53
GAIN LIMITS .................................................................................................................................................................. 55
DYNAMIC CHARACTERISTICS ................................................................................................................................... 55
ANTI-CLIP CONTROL ................................................................................................................................................... 56
QUICK RELEASE CONTROL ....................................................................................................................................... 57
GAIN SMOOTHING ....................................................................................................................................................... 57
INITIALISATION ............................................................................................................................................................ 58
RETUNE
TM
MOBILE PARAMETRIC EQUALIZER (EQ) ................................................ 59
DEFAULT MODE (5-BAND PARAMETRIC EQ) ........................................................................................................... 59
TM
RETUNE MOBILE MODE........................................................................................................................................... 60
EQ FILTER CHARACTERISTICS ................................................................................................................................. 60
DIGITAL MIXING ........................................................................................................... 62
DIGITAL MIXING PATHS .............................................................................................................................................. 62
DAC INTERFACE VOLUME BOOST ............................................................................................................................ 64
DIGITAL SIDETONE ...................................................................................................................................................... 64
DIGITAL-TO-ANALOGUE CONVERTER (DAC) ........................................................... 66
DAC DIGITAL VOLUME CONTROL .............................................................................................................................. 66
DAC SOFT MUTE AND SOFT UN-MUTE ..................................................................................................................... 68
DAC MONO MIX ............................................................................................................................................................ 69
DAC DE-EMPHASIS...................................................................................................................................................... 69
DAC SLOPING STOPBAND FILTER ............................................................................................................................ 70
DAC OVERSAMPLING RATIO (OSR) .......................................................................................................................... 70
OUTPUT SIGNAL PATH ............................................................................................... 71
OUTPUT SIGNAL PATHS ENABLE .............................................................................................................................. 72
HEADPHONE / LINE OUTPUT SIGNAL PATHS ENABLE ........................................................................................... 72
OUTPUT MUX CONTROL ............................................................................................................................................. 76
OUTPUT VOLUME CONTROL...................................................................................................................................... 76
ANALOGUE OUTPUTS ................................................................................................. 79
HEADPHONE OUTPUTS – HPOUTL AND HPOUTR ................................................................................................... 79
LINE OUTPUTS – LINEOUTL AND LINEOUTR............................................................................................................ 79
EXTERNAL COMPONENTS FOR GROUND REFERENCED OUTPUTS .................................................................... 80
REFERENCE VOLTAGES AND MASTER BIAS........................................................... 81
ANALOGUE REFERENCE AND MASTER BIAS .......................................................................................................... 81
LOW POWER PLAYBACK MODE ................................................................................................................................ 82
POP SUPPRESSION CONTROL .................................................................................. 83
DISABLED INPUT CONTROL ....................................................................................................................................... 83
CHARGE PUMP ............................................................................................................ 84
DC SERVO .................................................................................................................... 85
DC SERVO ENABLE AND START-UP ......................................................................................................................... 85
DC SERVO ACTIVE MODES ........................................................................................................................................ 88
DC SERVO READBACK ............................................................................................................................................... 90
DIGITAL AUDIO INTERFACE ....................................................................................... 90
MASTER AND SLAVE MODE OPERATION ................................................................................................................. 91
OPERATION WITH TDM ............................................................................................................................................... 91
BCLK FREQUENCY ...................................................................................................................................................... 92
w
PP, Rev 3.3, September 2012
4
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
