[wdmaudiodev] Re: Discovery of Analog Audio Device

  • From: "David Roach" <david.roach@xxxxxxxxxxxxxxxx>
  • To: <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Wed, 7 Nov 2007 08:09:05 -0600

Hello all,

Most HD Audio codecs now on the market support some type of impedance
sensing in hardware, in addition to simple detection of whether a jack is
physically plugged in. Almost all HD Audio codecs also feature some form of
multi-tasking support, to allow the analog I/O ports to change functions on
the fly.

The paper that Hakon provided a link to was the catalyst for various chip
companies to implement the impedance sensing functionality.

Appendix D of my book, High Definition Audio for the Digital Home, goes into
this subject much more deeply, and was written after many hard lessons were
learned.
http://optimalsound.net/hdaudiobook.html

I led the HW and SW teams for the first chip company to implement impedance
sensing, so the information in the appendix is very real, and not
theoretical.

Best,

David Roach
david.roach@xxxxxxxxxxxxxxxx
www.optimalsound.net

------------------------------

> Subject: [wdmaudiodev] Re: Discovery of Analog Audio Device
> Date: Tue, 6 Nov 2007 11:53:43 -0800
> From: Hakon Strande <hakons@xxxxxxxxxxxxxxxxxxxxx>
>
> I found it
>
> http://www.microsoft.com/whdc/device/audio/analog_impedance.mspx 
>
> Sincerely,
>
> Hakon Strande | Windows Sound Team PM | (p) 425.705.0637
>


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