I2S interface hardware definition and electrical connection mode

I2s Interface Overview

I2S Full name Inter-ic sound, Integrated interchip Voice, or abbreviated IIS, is the digital audio transmission standard that Philips defined in 1986 (revised in 1996) for the transmission of digital audio data between devices within the system, Examples include codec codec, DSP, digital input/output interface, ADC, DAC, and digital filter. In addition to being defined by Philips, I2S and I²c have no relationship whatsoever. The I2S hardware interface defines a serial clock SCLK, also called a bit clock (BCLK), which corresponds to each bit of digital audio, SCLK has 1 pulses, SCLK frequency =2* Sampling frequency * Sample bit number. Frame clock Lrck, used to toggle the left and right channel data, 1 is the Ieft channel, 0 is the sound channel, and the Lrck frequency equals the sampling frequency. Serial data SD, which is the audio data expressed in twos complement. Sometimes in order for the system to be better synchronized, another signal mclk, called the Master Clock, also known as the system clock (SYS clock), is typically 256 times times or 384 times times the sampling frequency. Remember, MCLK is not a must. Optional, look at the design requirements. Electrical Connection

IIS is a relatively simple digital interface protocol with no address or device selection mechanism.
On the IIS bus, only one primary and sending device can exist at the same time .
The primary device can be a sending device, a receiving device, or a co-ordination of the sending device and other control devices that accept the device.
In the IIS system, the device that provides the clock is the primary device.

Case Analysis

This is the IIS interface for RDA5981, which is a special interface:
SD line is divided into in and out two root, when it is output audio data is used OUT_SD, when it is to accept audio data is used IN_SD
Lrck and BCLK are also divided into in and out two groups, when the RDA5981 as a master is used out of the set of clocks when it is used as slave devices when using the in group clock.