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I bought the Terasic DE10 Standard and am having issues trying to run the demos related to audio.

I am trying to run the two demos, DE10_Standard_Audio, and DE10_Standard_i2sound, while connecting apple headphones to line out, and 3.5 lavalier microphone to mic in, but I am not able to record anything and play it back for the 1st demo, and I don't hear anything when I speak into the microphone for the second demo either. The microphone and headphones work fine on my laptop.

DE10 Standard user manual: https://www.intel.com/content/dam/altera-www/global/en_US/portal/dsn/42/doc-us-dsnbk-42-5505271707235-de10-standard-user-manual-sm.pdf

I am using a lavalier mic (https://www.amazon.com/Professional-Microphone-Omnidirectional-Recording-Conference/dp/B01AG56HYQ) and connecting it to the mic-in, and then using apple earphones to line-out.

The 2 demos are Audio Recording and Playing, and Karaoke Machine as listed in the manual. I did check that some of the other demos indeed do work.

Can anyone offer any advice at all? It really seems like the demos should work? I don't know what I'm doing wrong :(

I know this may be too general of a question, but I can provide any other information needed.

Thanks!!

EDIT: I have tried a TS, TRS, and a TRRS type jack for the microphone input, and neither of these work unfortunately

EDIT: I forgot to mention that I can hear when I directly breathe into the microphone, but nothing else. Unsure if this is relevant or not though.

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  • \$\begingroup\$ What have you done to determine that the appropriate bitstream is loaded, and operational? \$\endgroup\$
    – Chris Stratton
    Commented Sep 15, 2020 at 18:04
  • \$\begingroup\$ The professional mics I know generally use 48V phantom power so this isn't. But it'll require the usual electret supply voltage of up to 5V via about 5 kilohms source impedance. Does the DE10 board provide that? Check the board schematic and the Wolfson WM8731 datasheet. \$\endgroup\$
    – user16324
    Commented Sep 15, 2020 at 18:08
  • \$\begingroup\$ @ChrisStratton The bit stream is loaded and I can tell it's operational as there is some SSD stuff that works fine. \$\endgroup\$
    – Lokwill
    Commented Sep 15, 2020 at 19:49
  • \$\begingroup\$ @BrianDrummond I'm taking a look at the WM8731 datasheet, and I can't quite tell, I'm really sorry. I see there is a 10k resistor connected to the micin and it goes to an opamp which seems to give it a gain of 5. I don't see anything about a supply voltage or a source impedance, but I don't know if I'm interpreting the datasheet correctly. Could you please take a look? (statics.cirrus.com/pubs/proDatasheet/WM8731_v4.9.pdf) \$\endgroup\$
    – Lokwill
    Commented Sep 15, 2020 at 20:01
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    \$\begingroup\$ There are many different types of MICs , electrodynamic, electret,... not all connections, even if they all use 3.5mm jack, are equal. You have to read both manuals and then compare if those devices are compatible. \$\endgroup\$
    – Marko Buršič
    Commented Sep 15, 2020 at 20:52

2 Answers 2

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From the schematic in the other answer:

The phone jacks J2 (LINE IN) and J3 (LINE OUT) with L,R,NCL,NCR,and GND is a THREE ring jack (L,R,GND) and has two switch connections which probably connect to L,R with no socket present.

The Mic In jack J1 is another three ring jack with the Mic connected to L, GND (and nothing on R). It DOES connect to the MBIAS pin on the WM8371 so it is all set to power an electret mic, assuming MBIAS is correctly enabled in the chip.

The most likely problem is inserting a 4 ring jack (T R1 R2 S) with the mic connected to R2 and S, into a 3 ring T R S socket with the mic connections on T and S.

The mic is designed to work with newer jack connections (both headphone channels and mic on the same plug, as used in smartphones) while the board was designed back in the era of multimedia PCs with three jacks : phone/line out, mic in, line in.

You'll need to find or make an adapter, or source an older style mic.

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  • \$\begingroup\$ So, the mic actually comes with an adapter that converts the 3 ring adapter to a 2 ring adapter. Also the person above said the WM8731 is expecting a 5 contact jack which translates to a 4 ring jack, so I'm a bit confused? \$\endgroup\$
    – Lokwill
    Commented Sep 15, 2020 at 22:20
  • \$\begingroup\$ So you have an adapter already. Hope it's the right one. \$\endgroup\$
    – user16324
    Commented Sep 15, 2020 at 22:21
  • \$\begingroup\$ I've actually been always using it, and demos still don't work. It's a 4 to 3-PIN adapter. \$\endgroup\$
    – Lokwill
    Commented Sep 15, 2020 at 22:23
  • \$\begingroup\$ And where does it connect the microphone? Should only take seconds to buzz it out. Ring 2 to ... ? Sleeve to ... ? \$\endgroup\$
    – user16324
    Commented Sep 15, 2020 at 22:57
  • \$\begingroup\$ I'm not too sure what you're asking? I connect the mic to the adapter (the adapter is female TRRS to male TRS) and the adapter connects to the audio jack. I don't know what Ring 2 and Sleeve are, sorry... I'm pretty inexperienced \$\endgroup\$
    – Lokwill
    Commented Sep 15, 2020 at 23:27
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The board seems to use 5 contact 3.5mm jack:

enter image description here

While the MIC pictures show only 4 contacts on their 3.5mm jack

enter image description here

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  • \$\begingroup\$ Do you know it the codec requires a 5 pole connector because it has L,R,NCL,NCR,and GND? Or is it something else? \$\endgroup\$
    – Lokwill
    Commented Sep 15, 2020 at 21:23
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    \$\begingroup\$ The two extra contacts are the presense switches in standard T-R-S jacks (3 contact). \$\endgroup\$
    – Tom Carpenter
    Commented Sep 15, 2020 at 22:19
  • \$\begingroup\$ I currently have a TRS jack and the demos still don't seem to play. \$\endgroup\$
    – Lokwill
    Commented Sep 15, 2020 at 22:29

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