Please, read the below short note on I2S interface and provide your comments
I2S also known as Inter-IC Sound is a 3-wire serial interface used to connect digital audio interfaces to micro controllers or processors. In practical applications, hen a speaker or a microphone is to be interfaced to a micro controller, I2S is the interface of choice. The micro controller interfaces with audio codec using the I2S interface.
Why actually an I2S is required?
We know that audio signals are analog. So, we want to process these signals we need to convert to digital. I2S is the protocol which is specifically designed for communicating audio signals between ICs. This interface is intended to be used on the PCB and between the chips. Codecs mostly use this interface.
Signal connectivity
If we look at the Audio codec or the micro controller datasheet, I2S has the following interface signals.
SD - Serial data line
WS or LRCLK - Word Clock line
SCK or BCLK - Clock Line
Word clock line helps to select the channel type, whether it is left or right. when you see a stereo set up, you have left and right channels, so, to select ehe channel, LRCLK is used. Left audio is transmitted on the low cycle of the word select clock and the right channel is transmitted on the high cycle of the word select clock.
SCK is the master clock that drives the other signals. This is called the BIT Clock line.
Serial data line is used to transmit and receive the data.
The device generating Word select and SCK is the Master device
Synchronization
In some cases, to keep the micro controller and the audio CODEC interfaced to it in synch, Clock (MCLK or Master Clock) is input to the CODEC directly from the micro controller.
Other specifications:
I2S Uses standard TTL levels for communication. so, no need of level translator when microcontroller has to communicate with codec.
Standard clock rates of I2S include frequencies of 32KHz, 44.1KHz, or 48KHz. This is called the basic sample rate. From this frequency, based on the number of bits per channel and number of channels, the bit clock rate is calculated
Operates at a maximum frequency of 3.125MHz.
Data is transmitted in singed, two's complement format
Data word-lengths of 8, 10, 12, 14, 16, 18, 20, 24, or 32 bits are supported.
Why actually an I2S is required?
We know that audio signals are analog. So, we want to process these signals we need to convert to digital. I2S is the protocol which is specifically designed for communicating audio signals between ICs. This interface is intended to be used on the PCB and between the chips. Codecs mostly use this interface.
Signal connectivity
If we look at the Audio codec or the micro controller datasheet, I2S has the following interface signals.
SD - Serial data line
WS or LRCLK - Word Clock line
SCK or BCLK - Clock Line
Word clock line helps to select the channel type, whether it is left or right. when you see a stereo set up, you have left and right channels, so, to select ehe channel, LRCLK is used. Left audio is transmitted on the low cycle of the word select clock and the right channel is transmitted on the high cycle of the word select clock.
SCK is the master clock that drives the other signals. This is called the BIT Clock line.
Serial data line is used to transmit and receive the data.
The device generating Word select and SCK is the Master device
Synchronization
In some cases, to keep the micro controller and the audio CODEC interfaced to it in synch, Clock (MCLK or Master Clock) is input to the CODEC directly from the micro controller.
Other specifications:
I2S Uses standard TTL levels for communication. so, no need of level translator when microcontroller has to communicate with codec.
Standard clock rates of I2S include frequencies of 32KHz, 44.1KHz, or 48KHz. This is called the basic sample rate. From this frequency, based on the number of bits per channel and number of channels, the bit clock rate is calculated
Operates at a maximum frequency of 3.125MHz.
Data is transmitted in singed, two's complement format
Data word-lengths of 8, 10, 12, 14, 16, 18, 20, 24, or 32 bits are supported.
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