This page serves as documentation for the Aecho.

The Aecho is a standalone MP3 decoder subsystem - simply feed it some MP3 data through SPI and the audio will stream out through the onboard 3.5mm stereo jack.
You can also grab the unamplified "line-level" audio output from the included "GND-L-R" breakout.

It makes use of the STA013 MP3 decoder, CS4334 D/A converter and LM4811 headphone amplifier to provide a simple standalone solution for playing MP3 audio.

The decoder

The sta013 library is provided to control the MP3 decoder (STA013).

The D/A converter

The CS4334 from Cirrus converts the digital audio from the STA013 decoder to a stereo analog signal.
Its output is routed to the "GND-L-R" breakout pins, as well as the LM4811 headphone amplifier.

The headphone amplifier

The lm4811 library is provided to control the headphone amplifier (LM4811).