STM32F407IEH6 - I2S2_MCK and I2S3_MCK

[goranferenc]

Posted on September 15, 2014 at 17:21

Hi everybody!

We are currently working on some audio related project. We are using TI's ADC (PCM4201) and DAC (PCM1748) on our board and we will communicate with them using I2S. Now, we have to select appropriate microcontroller and one of the possibilities is STM32F407IEH6. 

So, the idea is to use one I2S for ADC and the second one for DAC. 

Can I2S2_MCK and I2S3_MCK be generated separately (two different frequencies) or these two pins output the same clock signal? We will need two different MCKs, because both ADC and DAC will work in slave mode and they will require different sampling rates at the same time.

Best regards,

Goran

[waclawek.jan]

Posted on September 16, 2014 at 09:52

The MCLKs are generated from a common source (see ''I2S clocks'' in the clock tree picture in RCC section of RM0090, fig.21) through dividing in the I2S/SPI module. It means, that the two MCLKs can be different, but they originate from the same source, i.e. ratio of their frequencies is a rational number.

JW

[goranferenc]

Posted on September 16, 2014 at 10:50

OK, thank you very much Jan.

Goran