Audio Interface I²S
What is I²S?
I²S (Inter-IC Sound) is an electronic serial bus interface standard used for connecting digital audio devices together, this standard was first introduced by Philips Semiconductor in 1986. It is used to transfer PCM audio data between integrated circuits in electronic devices.
The I²S Hardware Interface:
1. Bit clock line
Formally called "Continuous Serial Clock (SCK)". Usually written as "bit clock (BCLK)".
That is, each bit of data corresponding to digital audio, SCLK has a pulse.
The frequency of SCLK = 2 × sampling frequency × number of sampling bits.
2. Word clock line
Formally known as "word selection (WS)". [Commonly referred to as "LRCLK" or "Frame Sync (FS)".
0 = left channel, 1 = right channel
3. At least one multiplexed data line
Formally called "Serial Data (SD)", but can be called SDATA, SDIN, SDOUT, DACDAT, ADCDAT, etc.
Timing diagram of I²S