Datasheet
4D SYSTEMS SOMO-II
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SOMO-II Embedded Audio-Sound Module
1. Description
The SOMO-II (SOund Module 2) is a tiny Audio-
Sound module that can play MP3 audio files stored
on a micro-SD card (or USB 2.0 Flash drive with
extra components), such as voice and music.
The SOMO-II features an on board 16bit MCU,
specifically designed for hardware audio decoding.
The SOMO-II supports both FAT16 and FAT32
formatted micro-SD and USB Flash Drives up to
32Gb in size, and features a 24-bit DAC output
with support for all MP3 bit rates (11172-3 &
ISO13813-3 3 Layer Audio Decoding) with 8-Khz to
48Khz Sampling Rate.
Files can be stored in the root folder of the micro-
SD or USB Flash drive, else in folders. It supports
up to 99 folders and every folder can contain up to
255 songs.
Audio files can be easily loaded to the micro-SD
card or USB Flash drive using a PC/Laptop, and
inserted into the SOMO-II for playback. No
external software is required.
The compact 16pin drop-in-module takes up very
minimal board space and is ideal for any
application that requires embedded audio.
The SOMO-II features an on board mono Amplifier
capable of driving an 4ohm 3 Watt speaker directly
(see Section 4.4). It also features stereo DAC
output for connecting directly to headphones or
into an external amplifier.
The module offers two modes of operation,
SERIAL-MODE and the KEY-MODE.
The SERIAL-MODE provides a simple 2-wire Serial
UART interface to any micro-controller via its TX
and RX pins. Audio operations such as PLAY,
PAUSE, STOP, NEXT, PREVIOUS and VOLUME
control functions are all available to the host micro
via simple serial commands, along with many
more. SERIAL-MODE features a CRC check.
The KEY-MODE provides a stand-alone operation
where a host micro is not required. It is possible to
control the module with just 2 buttons, or an array
of buttons can be added via various resistor values
to get full control of the module without having to
use an external processor.
With only 2 push buttons, a 3.3V to 5V battery and
a speaker, an extremely compact and low
component count MP3-Player like system can be
implemented.
In short, the SOMO-II offers a very flexible,
compact and low cost embedded audio solution
for many applications.
2. Features
Low-cost module for all embedded Audio Sound
applications.
Supports all MP3 bit rates 11172-3 &
ISO1381303 with Samples rates from 8Khz to
48Khz
24-bit DAC output, dynamic range support
90dB, SNR supports 85dB
SERIAL MODE: Supports a 2-Wire 3.3V TTL
UART interface to any micro-controller.
KEY-MODE: Supports a simple stand-alone
operation without a host micro.
Mono amplified Speaker output, capable of
driving a 4ohm speaker at 3 Watts (5V supply).
DAC audio output to use with an external
amplifier or with headphones.
On-board micro-SD memory card adaptor for
storing of audio, voice and music files
Supports up to 32GB micro-SD memory cards,
and both FAT16 and FAT32 file formats.
Supports up to 32GB USB 2.0 Flash Drive, when
used in conjunction with an USB socket (not on
board), supporting both FAT16 and FAT32 file
formats.
Compact size measuring only 21.0mm Long x
20.5mm Wide x 11.3mm High.
Weight ~2g.
3.3V to 5.0V DC voltage range (single supply).
RoHS and CE Compliant.