VS1053B Datasheet, PDF (74/79 Pages) List of Unclassifed Manufacturers – Ogg Vorbis/MP3/AAC/WMA/MIDI AUDIO CODEC

VLSI
Solution ^y
VS1053b preliminary
VS1053B
10. VS1053B REGISTERS
10.12 VS1053b Audio Path
MICN
MICP
LINE1
LINE2
MIC AMP
MUX
Stereo ADC
Audio
FIFO
Sample-Rate
Converter
SRC
Volume
Control
+
Sigma-Delta
Modulator
SDM
ADC
Analog
Drivers
LEFT
RIGHT
CBUF
I2S
Figure 16: VS1053b ADC and DAC data paths
In IMA ADPCM encoding mode the data from Analog-to-Digital conversion is first processed in 48 kHz
or 24 kHz samplerate. The firmware performs DC offset removal and gain control (automatic or fixed),
then redirects the data to the audio FIFO. From there the data goes to the samplerate converter with a
delay of only a couple of samples. The samplerate converter upsamples the data to XTALI/2 (6.144 MHz
with the default clock), from where it is resampled to either 1×, 2×, or 3× the requested samplerate.
The additional decimation is performed in software to get the final data at the right frequency for IMA
ADPCM encoding or for PCM samples.
Version 0.5, 2007-12-03
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