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Hi, I am using STM32F413ZHT6 micro-controller for one of my application. I need reference design for I2S interface. Datasheet has not explained much about the pins functionality.

kumar singh
Associate II
 
1 ACCEPTED SOLUTION

Accepted Solutions

> I2S2_SD and I2S2ext_SD direction

It depends on how you set the SPIx_I2SCFGR.I2SCFG field in the respective modules (SPI2/I2S2 and I2S2Ext): if to transmit, the respective pin is output, if to receive, the pin is input. See the I2S subchapter of SPI chapter in RM.

This allows you flexibility in routing the PCB.

JW

View solution in original post

5 REPLIES 5

Manufacturers of I2S-compatible devices notoriously label the signals in various ways.

The standard says:

3.0 THE I 2 S BUS

As shown in Figure 1, the bus has three lines:

• continuous serial clock (SCK);

• word select (WS);

• serial data (SD);

and the device generating SCK and WS is the master.

ST follows this nomenclature relatively well.

standard                   ST         various manufacturers
SCK (Serial Clock)         I2Sx_CK    SCLK, BICK (Bit Clock)
WS  (Word Select)          I2Sx_WS    LRCK (Left-Right Clock)
SD  (Serial Data)          I2Sx_SD    SDIN/SDOUT, SDTI/SDTO, RXDAT/TXDAT, DACDAT/ADCDAT

There is an additional nonstandard but often used signal I2Sx_MCK/MCLK.

The SPI/I2S module in STM32 is simplex but the data direction is settable (Rx/Tx) that's why it's not marked at the pin, and it's marked as I2Sx_SD.

There are auxiliary stripped-down I2S-slave-only modules, I2SxExt - as they are slave-only and their WS and SCK clocks are connected internally to their respective "master" module, they have only a single pin brought out, I2SxExt_SD.

Refer to the F4 Disco boards (e.g. https://www.st.com/en/evaluation-tools/stm32f4discovery.html ) for reference, they have an I2S DAC on board. Maybe the EVAL boards have I2S device on board, too.

JW

kumar singh
Associate II

Hi waclawek.jan,

Thanks for your reference. I wanted to know about I2S2_SD and I2S2ext_SD direction I will have a look at it in the discovery board. I hope it should help

Narendra

> I2S2_SD and I2S2ext_SD direction

It depends on how you set the SPIx_I2SCFGR.I2SCFG field in the respective modules (SPI2/I2S2 and I2S2Ext): if to transmit, the respective pin is output, if to receive, the pin is input. See the I2S subchapter of SPI chapter in RM.

This allows you flexibility in routing the PCB.

JW

kumar singh
Associate II

Thanks for your clarification.

Piranha
Chief II

SAI peripheral is much better for I2S and other audio protocols. It should be the first choice.