VS1033 is a single-chip MP3/AAC/WMA/MIDI
audio decoder and ADPCM encoder. It contains
a high-performance, proprietary low-power DSP
processor core VS DSP4, working data memory,
5 KiB instruction RAM and 0.5 KiB data RAM
for user applications, serial control and input data
interfaces, upto 8 general purpose I/O pins, an
UART, as well as a high-quality variable-samplerate
mono ADC and stereo DAC, followed by an
earphone amplifier and a common voltage buffer.
VS1033 receives its input bitstream through a serial
input bus, which it listens to as a system slave.
The input stream is decoded and passed through a
digital volume control to an 18-bit oversampling,
multi-bit, sigma-delta DAC. The decoding is controlled
via a serial control bus. In addition to the
basic decoding, it is possible to add application
specific features, like DSP effects, to the user RAM memory.