STM32F4 DISCOVERY WAVE PLAYING ABD RECORDING

[sami]

Posted on January 21, 2013 at 15:10

Hello ;

I have project where I have to record and play wav files  simultaneously , but it is not clear in the datasheet of cs43L22 if that possibe or not  ; Could anyone confirm that please if possible or not ? Regards

[Tesla DeLorean]

Posted on January 21, 2013 at 16:05

I have project where I have to record and play wav files  simultaneously , but it is not clear in the datasheet of cs43L22 if that possibe or not.

It's pretty clear from the CS43L22 data sheet it's an OUTPUT only device, so recorded data is never going to come from this device. You need to be looking at the audio SOURCES. You need to look at how those sources are configured, if they share pins or resources, etc.

[sami]

Posted on January 22, 2013 at 08:47 Thank you clive ; In the sTM32f4 discovery board the output of the micriphone PCM is connected to analog input of CS43L22 and the record is being transfered to the microcontroller then to the USB flash ; so my question stm32f4 discovery can play and record wav but can we do that  simultaneously ? Thank you again Clive Regards

[Tesla DeLorean]

Posted on January 22, 2013 at 09:21

It's going to a mixer which you don't have to select, you'd sample via PC3 (ADC1_IN13), the play and record operate independently, there will be a lag if you try to loop back the sample. You can also use the STM32's DAC.

[sami]

Posted on January 23, 2013 at 13:11

If you look to the shematic of the discovery board ; the PDM_out is fed to Cs43l22 ; so why is it fed there ? infact that mixed me ...

In other case ; i think it is possible to play wave using CS43L22 and recording the wave at the same time using SPI2 and PDM.. Am I wrong ? thank you

[Tesla DeLorean]

Posted on January 23, 2013 at 15:36

As I said before, the play and record operate independently, that is they can work separately, or together, and at different rates.

The analogue audio input to the CS43L22's mixer provides for what we call in the telephony business a ''side tone'', where some signal from the microphone is pushed into the speaker of the headphone/handset to provide feedback to the user and allow them to control the loudness of their speaking.

http://pocketnow.com/2012/09/21/sidetone-the-best-calling-feature-you-never-heard-of

[sami]

Posted on January 24, 2013 at 08:46 What is the goal of using 3v as power instead of 3.3v in the discovery board ?

[Tesla DeLorean]

Posted on January 24, 2013 at 13:25

What is the goal of using 3v as power instead of 3.3v in the discovery board ?

Reducing power consumption, we run our boards below 3V? Also depends on what your interfacing too. The core runs down at 1.2-1.25 V, reducing the drop on the regulator is probably desirable too.