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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