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What is the I2S bus

Inter-IC Sound (I2S) is a digital communication protocol designed specifically to transmit audio between electronic devices. Unlike other buses like I2C, which are used to transmit general data between chips, I2S is optimized to send audio data of high quality in real time.

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How does I2S work?

The I2S bus uses several lines to transmit the information:
  • Serial Data (SD): Where the audio data travels.
  • Serial Clock (SCK): Marks the rhythm at which the bits are sent.
  • Word Select (WS): Indicates if the data corresponds to the left or right channel (in stereo audio).
The SCK and WS lines are common to all devices that are connected to the I2S bus. However, both the speaker and the microphone have their own SD lines. This structure allows the audio to be transmitted in a synchronized and lossless manner, ideal for applications where sound quality is important.

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Why use I2S for digital audio?

  • Quality: Allows digital audio transmission without interference or typical noise of analog signals.
  • Synchronization: Ensures that the data arrives at the right time, avoiding phase shifts or distortions.
  • Compatibility: It is the standard in most modern audio chips, facilitating the integration of microphones and digital speakers.
In the Kode Dot, both the microphone and the speaker are connected via I2S, which allows recording and reproducing sound with great fidelity and efficiency.