PDM Filter problem

baiyongchen · ‎2014-01-22

Posted on January 22, 2014 at 10:08

Hi, can someone help me solve a problem on PDM Filter Init function:

PDM_Filter_Init() cannot return from it in second invoke.

How can we reset the function and call it again?

Thanks!

..........

RCC->AHB1ENR |= RCC_AHB1ENR_CRCEN;

Filter.LP_HZ = 8000;

Filter.HP_HZ = 10;

Filter.Fs = 16000;

Filter.Out_MicChannels = 1;

Filter.In_MicChannels = 1;

PDM_Filter_Init((PDMFilter_InitStruct *)&Filter);

...........

RCC->AHB1ENR |= RCC_AHB1ENR_CRCEN;

Filter.LP_HZ = 8000;

Filter.HP_HZ = 10;

Filter.Fs = 32000;

Filter.Out_MicChannels = 1;

Filter.In_MicChannels = 1;

PDM_Filter_Init((PDMFilter_InitStruct *)&Filter);//will dead loop here

.................

Tesla DeLorean · ‎2014-01-22

Posted on January 22, 2014 at 16:09

I don't see the value of enabling the CRC unit the second time around.

I'm not familiar with the code in question. So does the second invocation crash into a Hard Fault or something, or is it getting stuck in a loop internally.

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baiyongchen · ‎2014-01-23

Posted on January 23, 2014 at 10:08

It is getting stuck in a loop internally.

I found the solution:

Add reset CRC DR ,it work well.

..........

CRC->CR = CRC_CR_RESET;//Reset CRC DR

RCC->AHB1ENR |= RCC_AHB1ENR_CRCEN;

Filter.LP_HZ = 8000;

Filter.HP_HZ = 10;

Filter.Fs = 16000;

Filter.Out_MicChannels = 1;

Filter.In_MicChannels = 1;

PDM_Filter_Init((PDMFilter_InitStruct *)&Filter);

...........

CRC->CR = CRC_CR_RESET;//Reset CRC DR

RCC->AHB1ENR |= RCC_AHB1ENR_CRCEN;

Filter.LP_HZ = 8000;

Filter.HP_HZ = 10;

Filter.Fs = 32000;

Filter.Out_MicChannels = 1;

Filter.In_MicChannels = 1;

PDM_Filter_Init((PDMFilter_InitStruct *)&Filter);//will dead loop here

.................