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STM32F7 discovery audio line-in

konrad2399
Associate II
Posted on October 06, 2015 at 21:10

Hi.

I've started to play with STM32F7 discovery. I got to DSP audio example from hands-on and I would like to use line-in instead of microphones. Unfortunately when I've changed

BSP_AUDIO_IN_OUT_Init(INPUT_DEVICE_DIGITAL_MICROPHONE_2, OUTPUT_DEVICE_HEADPHONE, 90, DEFAULT_AUDIO_IN_FREQ);

to

BSP_AUDIO_IN_OUT_Init(INPUT_DEVICE_INPUT_LINE_1, OUTPUT_DEVICE_HEADPHONE, 90, DEFAULT_AUDIO_IN_FREQ);

Only thing that's coming is noise. Could anyone help me to get line-in working? Best regards Konrad #https://github.com/laurent-lator #stm32f7-audio
24 REPLIES 24
konrad2399
Associate II
Posted on January 30, 2016 at 15:48

I can't believe it's that simple :)

Thank you.

hpeev1972
Associate II
Posted on February 18, 2016 at 23:25

Yes, volume < 70!

I made same experience.

And, if I remember correctly: the ADC/DAC chip is configured with an audio cross connect (inside the onboard ADC/DAC chip, this WM9... chip). I have modified slightly the config for this chip (done via very low level driver code, via I2C) and it works fine for me.

I think, this DAC chip has feedback or taken some audio from another channel/input and volume > 70 results in just distortions (noise) due to active audio cross/feedback.

misterstarshine
Associate III
Posted on October 07, 2016 at 17:50

Hi David.

I managed to build your program with System Workbench. Have you found out what causes the noise yet? The noise level is just totally ridiciolus. Totally useless in its current configuration.

Chirag Parmar
Associate

Hello Nickname8353,

Can you tell me from where can I finde DSP example code for STM32F7 Discovery? I am trying to generate audio signal from audio out. and also taking input from audio line in and same signal to audio out. It will be great helpfull.

Thank You.