SGTL5000XNAA3 Datasheet, PDF (40/84 Pages) Freescale Semiconductor, Inc – Low Power Stereo Codec with Headphone Amp

SGTL5000
DATASHEET
Please refer to section 6.3.2 for a programming example that shows how load the fil-
ter coefficients when the end-user changes the preset.
PEQ can be disabled (pass-through mode) by writing 0 to DAP_AUDIO_EQ->EN
bits.
5.9.4.2. 5-Band Graphic EQ
The 5-band graphic equalizer is implemented using 5 parallel second order IIR fil-
ters. All filters are implemented using biquad filters whose coefficients are pro-
grammed to set the bands at specific frequency. The GEQ bands are fixed at
115Hz, 330Hz, 990Hz, 3000Hz, and 9900Hz. The volume on each band is indepen-
dently adjustable in the range of +12dB to -11.75 dB in 0.25dB steps.
Please refer to section 6.3.3 for a programming example that shows how to change
the GEQ volume
5.9.4.3. Tone Control
Tone control comprises treble and bass controls. The tone control is implemented
as one 2nd order low pass filter (bass) and one 2nd order high pass filter (treble).
Please refer to section section 6.3.4 for a programming example that shows how to
change Bass and Treble values.
5.9.5.
Automatic Volume Control (AVC)
An Automatic Volume Control (AVC) block is provided to reduce loud signals and
amplify low level signals for easier listening. The AVC is designed to compress
audio when the measured level is above the programmed threshold or to expand
the audio to the programmed threshold when the measured audio is below the
threshold. The threshold level is programmable with allowed range of 0dB to -96 dB.
Figure 18 shows the AVC block diagram and controls.
Input from
Dual Input Mixer
DAP_AVC_THRESHOLD
Threshold
Level
Compare
If < Threshold
Decay (0.05dB/s to ~200dB/s)
DAP_AVC_DECAY
DAP_AVC_THRESHOLD -> MAX_GAIN
Volume
Control
Output To
SGTL Surround
If > Threshold
Attack (0.8dB/s to ~3200dB/s)
DAP_AVC_ATTACK
Figure 18. DAP AVC Block Diagram
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SGTL5000 EA2 DS-0-3