{"id":8923,"date":"2022-05-22T09:40:15","date_gmt":"2022-05-22T13:40:15","guid":{"rendered":"https:\/\/dronebotworkshop.com\/?p=8923"},"modified":"2023-04-11T14:23:07","modified_gmt":"2023-04-11T18:23:07","slug":"esp32-i2s","status":"publish","type":"post","link":"https:\/\/dronebotworkshop.com\/esp32-i2s\/","title":{"rendered":"Sound with ESP32 – I2S Protocol"},"content":{"rendered":"\n

\"Download<\/a> \"Parts<\/a> \"View<\/a> \"Download<\/a><\/p>\n

Audio meets ESP32 today, as we examine the I2S protocol for digital audio.<\/span><\/p>\n

<\/div>\n

 <\/p>\n

Introduction<\/span><\/h2>\n

If you are browsing through the specification sheet for an ESP32 device, you might run across the term \u201cI2S\u201d. At a glance, you may just think that it\u2019s another form of I2C, and the \u201cI2\u201d does indeed stand for the same thing, \u201cInter-Integrated Circuit\u201d. But that\u2019s where the similarity ends.<\/span><\/p>\n

I2S is a protocol for transferring digital audio. The audio quality can range from telephone-grade to ultra-high fidelity, and you can have one or two channels.<\/span><\/p>\n

\"\"<\/a>
Image credited to Tshirt Superstar – Music<\/figcaption><\/figure>\n

Today we will be exploring the use of I2S with the ESP32, and we\u2019ll build a few projects that use the I2S protocol.<\/span><\/p>\n

Let\u2019s get going!<\/span><\/p>\n

I2S & Digital Audio<\/span><\/h2>\n

The <\/span>Inter-Integrated Circuit Sound Protocol, or I2S<\/span><\/a>, was developed by Phillips Semiconductors in 1986. As you might recall, Phillips also developed the I2C protocol, and both protocols were built to serve a similar need.<\/span><\/p>\n

Both I2C and I2S addressed the need for compatibility between integrated circuits that handled data and sound information. Standardized protocols for transferring data and sound would allow designs using ICs from different manufacturers, which is a good thing for everybody.<\/span><\/p>\n

In order to understand I2S, it\u2019s a good idea to also understand how digital audio works. Here\u2019s a quick refresher in case you aren\u2019t familiar with the concept, if you are then feel free to skip it!<\/span><\/p>\n

Digital Audio<\/span><\/h3>\n

Sound by its own nature is analog, and, prior to the development of digital sound, audio equipment was also analog. The vibrations of sound on a transducer like a microphone can be amplified and then sent to a speaker, whose cone reproduces those vibrations.<\/span><\/p>\n

Getting the sound from the microphone to the speaker, especially if you wanted to record it and play it back on the speaker later, involved a lot of analog electronics. Even the best analog electronics will induce electrical noise and distortion in the signal, although modern designs are impressively clean.\u00a0\u00a0<\/span><\/p>\n

\"\"<\/p>\n

Digital audio was touted as a way to eliminate those distortions of the sound. With digital audio, the sound is sent to an analog to digital converter (ADC) to create a digital representation of it. This can then be stored or transmitted without any degradation. On the other end, the digital signal goes through an equivalent digital to analog converter (DAC), which recreates the analog input and is then amplified to drive a speaker.<\/span><\/p>\n

\"\"<\/p>\n

A digital audio signal is not, of course, a perfect representation of the original signal. The quality of the signal is dependent upon two parameters that apply to both the ADC and DAC:<\/span><\/p>\n