VS1001K
VLSI
DATASHEET
y
Solution
7. FUNCTIONAL DESCRIPTION
7 Functional Description
7.1 Main Features
VS1001k is based on a proprietary digital signal processor, VS DSP. It contains all the code and data
memory needed for MPEG audio decoding, together with serial interfaces, a multirate stereo audio DAC
and analog output amplifiers and filters.
VS1001k can play all MPEG 1 and 2 layer 3 files, as well as so-called MPEG 2.5 layer 3 extension
files with all sample rates and bitrates. In addition, variable bitrate (VBR) is also supported. With
VBR, and depending on the song, near-cd quality can be achieved with approximately 100 kbits/s for
stereo music sampled at 44100 Hz, whereas old encoders required 128 kbits/s for the same task. As
both commercial and free (http://www.mp3dev.org/) high-quality VBR encoders are nowadays widely
available, MP3 format is getting better as it is maturing.
7.2 Data Flow of VS1001k
SM_BASS = 0
A1ADDR = 0
L
SDI
Bitstream
FIFO
MP1/2/3
decoding
Bass/treble
enhancer
User
application
Volume
control
Audio
FIFO
S.rate.conv.
and DAC
R
16384 bits
SM_BASS = 1
A1ADDR != 0
VOL
512 stereo
samples
Figure 10: Data Flow of VS1001k.
First, MP3 data is input through the SDI bus.
After decoding, data may be sent to the Bass/treble enhancer depending on SCI register MODE’s bit
SM BASS.
Then, if SCI register AIADDR is non-zero, application code is executed from the address pointed to by
AIADDR. For more details, see Chapters 7.5.10 and Application Notes for VS10XX.
After the optional user application, the signal is fed to the volume control unit, which also copies the
data to the Audio FIFO.
The Audio FIFO holds the data that is read by the Audio interrupt (Chapter 9.5.1) and fed to the sample
rate converter and DACs. The size of the audio FIFO is 512 stereo (2×16-bit) samples
The sample rate converter converts all different sample rates to CLKI/512 and feeds the data to the DAC,
which in order makes a stereo in-phase signal. This signal is then forwarded to the earphone amplifier.
Version 4.11, 2003-09-18
20
ETC [ ETC ]
