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osxAcousticEC Implementation on STM32F4-DISCOVERY

Question asked by Nikil Rao on May 18, 2017
Latest reply on Feb 19, 2018 by Mojtaba Hajiabadi

Hey everyone,

 

I'm trying to implement the osxAcousticEC library on a STM32F4-DISCOVERY. The first problem was that I wasn't able to compile the library as it is and had to change this in system_stm32f4xx.c - 

 

-    __I uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};

 

+   const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+   const uint8_t APBPrescTable[8] = {0, 0, 0, 0, 1, 2, 3, 4};

 

I was able to compile after making the above changes. However, when I connect the board to the PC and observe the audio output on Audacity, I just see a large amount of noise on the first channel (Channel with echo cancellation) and lesser noise on the second channel. I tried commenting the call to the function "Send_Audio_to_USB" so that there's no audio sent to the USB at all. The second channel is now empty but there's still the same noise in the first channel. I've tried different boards and by connecting an external microphone instead of the on-board microphone but still have the same error. Can somebody help me out?

 

Thanks a lot in advance!

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