TDA7786 datasheet(19/54 Pages) STMICROELECTRONICS

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TDA7786, TDA7786M

Function description

2.15

I2S - serial audio interface

The audio SAI serves as stereo input/output audio bus interface (e.g. to an external audio

processor, or from an external HD decoder) using the I2S protocol. The latter calls for a bit

clock line, a word select line and data lines; the SAI interface on the TDA7786x has one

input data line and one output data line.

The audio SAI lines are: SAI_AUDIO_CLK (pin 37, bit clock line), SAI_AUDIO_WCLK (pin

38, word select (frame) clock line), SAI_AUDIO_DO (pin 39, data output line),

SAI_AUDIO_DI (pin 40, data input line). In master mode SAI_AUDIO_BCLK and

SAI_AUDIO_WCLK are outputs, in slave mode these pins are inputs.

The input and output data lines are operated at the same sampling frequency.

The bit clock has one pulse for each discrete bit of data on the data lines. The bit clock

operates at a frequency which is a multiple of the sample rate, and is equal to the sampling

frequency times the number of bits per word times two.

Figure 7. I2S interface timing (receiver)

Note:

The polarity of the signals and the data bit-shift direction can be selected by configuration

bits.

Table 6. Audio I2S configuration overview

SAI

1x2 In

and

1x2 Out

16/32

16/24

I2S

M/S

32-48

12.288 MHz

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