Hi,
I2S is a standard for digital audio, originally made by Philips and Sony back when they put together the CD format. It's pretty straightforward. A word clock starts out 0 for the left sample, then goes to 1 for the right sample. Digital data is transferred MSB-first on the edges of the bit clock. The number of bits may be almost arbitrary, since a DAC stops latching after it has received its share of bits for its resolution. The tricky bit about I2S is that it's synchronous with music, and more importantly that a "dead tick" occurs after a word clock edge, before the MSB of the next sample. To make things more complicated, if all bit clock ticks are needed to convey audio samples (what I call "bumper-to-bumper" I2S), the LSB of the previous sample is transmitted during the "dead tick".
What this boils down to is that I2S is straightforward between audio equipment which has it enabled, and a major hassle for MCU designers who try to fit it into existing serial port hardware.
I expect built and tested hardware in about two weeks, crossing my fingers that everything works out.
Cheers,
Børge
I2S is a standard for digital audio, originally made by Philips and Sony back when they put together the CD format. It's pretty straightforward. A word clock starts out 0 for the left sample, then goes to 1 for the right sample. Digital data is transferred MSB-first on the edges of the bit clock. The number of bits may be almost arbitrary, since a DAC stops latching after it has received its share of bits for its resolution. The tricky bit about I2S is that it's synchronous with music, and more importantly that a "dead tick" occurs after a word clock edge, before the MSB of the next sample. To make things more complicated, if all bit clock ticks are needed to convey audio samples (what I call "bumper-to-bumper" I2S), the LSB of the previous sample is transmitted during the "dead tick".
What this boils down to is that I2S is straightforward between audio equipment which has it enabled, and a major hassle for MCU designers who try to fit it into existing serial port hardware.
I expect built and tested hardware in about two weeks, crossing my fingers that everything works out.
Cheers,
Børge
