how to change microphone ports in usb-audio-mic-array-software? Topic is solved

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Bootucal
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how to change microphone ports in usb-audio-mic-array-software?

Post by Bootucal »

I have a xcore-array-microphone-board which is running the app_usb_aud_mic_array software. It is working so far. But I want to expand it with more PDM-Microphones via the expansion header.
As my first step I tried to change the pins of the already implementet 8 PDM-microphones to the pins of external PDM microphones. So I could see if that works. But I can´t find out how to do that.
In the module_usb_audio is a file called pcm_pdm_mic.xc in which I found the following code:

Code: Select all

/* Hardware resources */
in port p_pdm_clk                = PORT_PDM_CLK;
in buffered port:32 p_pdm_mics   = PORT_PDM_DATA;
in port p_mclk                   = PORT_PDM_MCLK;
clock pdmclk                     = on tile[PDM_TILE]: XS1_CLKBLK_3;
Can anybody tell me where PORT_PDM_DATA is defined? I guess it would be the right point to implement my changes...
Thanks for any help!!


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Luanvt4_fpt
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Joined: Wed Sep 12, 2018 9:13 am

Post by Luanvt4_fpt »

You can edit in your project file (for example: vfspk_base_*.xn).
<Port Location="XS1_PORT_8B" Name="PORT_PDM_DATA"/>
Please choose location has same size (8, 4, or 1)
Bootucal
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Post by Bootucal »

Thank you verry much!
Is there a possibility to group 4 one-Bit ports to one 4-bit port? I can adress all microphone-pins with XS1_PORT_8B but the pins of the expansion-header are only adressable like XS1_PORT_1G, XS1_PORT_1H, XS1_PORT_1I and so on...
But it would be nice if I could define a PORT_PDM_DATA_2 with all external microphones.
Hugo
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Joined: Fri Jan 04, 2019 4:51 pm

Post by Hugo »

i face an issue while defining my PORT_PDM_DATA. suggest some good solutions
Luanvt4_fpt
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Post by Luanvt4_fpt »

Is there a possibility to group 4 one-Bit ports to one 4-bit port?
I think it can.
The XS1_PORT_8B is also a collection of 8 different pin positions.
Chapter 4 in this document "XVF3000/XVF3100-TQ128 Datasheet". Hope can help you.
Bootucal
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Joined: Thu Jan 03, 2019 12:06 pm

Post by Bootucal »

As the support replied to my question, it is not possible to group ports up. So there is no way to get external microphones running at the Xmos XCore Array Microphone board, as the pdm_library expects a 8-bit port as input and the expansion-header of the microphone-array board is only adrassable with 1-bit ports. The product-brief is simply wrong with claiming that it would be possible to extend the board to up to 32 microphones.
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