[QUERY] [AUDIO][OMAP3 EVM] arecord not working on OMAP3 EVM

[QUERY] [AUDIO][OMAP3 EVM] arecord not working on OMAP3 EVM

[Koyamangalath, Abhilash]

Hi all
While testing audio capture (using arecord e,g.),I'm getting only noise in the (zeroed out) output buffers on the OMAP3 EVM.
I have enabled AUXL and AUXR mic inputs through alsamixer, which according to the schematics are connected to the "Audio In"
connector on the board, even though the TWL4030 reg list does not allow me any ways ( or so I think) to specify mic-bias for 
these aux inputs.
With AUXL and AUXR muted - I get only silence, which seems to make sense.
Is there any basic startup setting I'm missing, maybe specific to OMAP3 EVM?
Has anyone seen anything like this before, and could provide pointers?

I'm running a kernel based on 2.6.37-rc7 and audio playback is working fine for me.




Thanks in advance
Abhilash

Re: [QUERY] [AUDIO][OMAP3 EVM] arecord not working on OMAP3 EVM

[Peter Ujfalusi]

On 01/20/11 17:26, ext Koyamangalath, Abhilash wrote:
> Hi all
> While testing audio capture (using arecord e,g.),I'm getting only noise in the (zeroed out) output buffers on the OMAP3 EVM.
> I have enabled AUXL and AUXR mic inputs through alsamixer, which according to the schematics are connected to the "Audio In"
> connector on the board, even though the TWL4030 reg list does not allow me any ways ( or so I think) to specify mic-bias for 
> these aux inputs.

Well, it is auxiliary input (line in). You do not need bias for it.
I do not have access to OMAP3 EVM documentation, but Beagle also have
AUXL/R as input.
I guess you need to use correct cable, and correct source for the input
(stereo jack I suppose).

> With AUXL and AUXR muted - I get only silence, which seems to make sense.
> Is there any basic startup setting I'm missing, maybe specific to OMAP3 EVM?

Beagle?

> Has anyone seen anything like this before, and could provide pointers?

My bet goes for the wrong cable/accessory pair.

-- 
Péter
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RE: [QUERY] [AUDIO][OMAP3 EVM] arecord not working on OMAP3 EVM

[Koyamangalath, Abhilash]

Thanks Peter, 
Your comment helped.

> -----Original Message-----
> From: Peter Ujfalusi [mailto:peter.ujfalusi@nokia.com]
> Sent: Friday, January 21, 2011 1:27 PM
> To: Koyamangalath, Abhilash
> Cc: linux-omap@vger.kernel.org; alsa-devel@vger.kernel.org
> Subject: Re: [QUERY] [AUDIO][OMAP3 EVM] arecord not working on OMAP3 EVM
> 
> On 01/20/11 17:26, ext Koyamangalath, Abhilash wrote:
> > Hi all
> > While testing audio capture (using arecord e,g.),I'm getting only noise
> in the (zeroed out) output buffers on the OMAP3 EVM.
> > I have enabled AUXL and AUXR mic inputs through alsamixer, which
> according to the schematics are connected to the "Audio In"
> > connector on the board, even though the TWL4030 reg list does not allow
> me any ways ( or so I think) to specify mic-bias for
> > these aux inputs.
> 
> Well, it is auxiliary input (line in). You do not need bias for it.
> I do not have access to OMAP3 EVM documentation, but Beagle also have
> AUXL/R as input.
> I guess you need to use correct cable, and correct source for the input
> (stereo jack I suppose).
No need of bias precludes using a MIC, so I tried by connecting a Line-in/out audio cable (a cable with a 3.5 mm audio jack on each end) fed from the PC and it worked, thanks. Originally, I had connected a head-phone mic directly to the audio-in port, which it seems, rather expects a dc-biased and/or a pre-amplified signal.

> 
> > With AUXL and AUXR muted - I get only silence, which seems to make
> sense.
> > Is there any basic startup setting I'm missing, maybe specific to OMAP3
> EVM?
> 
> Beagle?
> 
> > Has anyone seen anything like this before, and could provide pointers?
> 
> My bet goes for the wrong cable/accessory pair.
Bang On.
> 
> --
> Péter
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