Question about Texas Instruments C6711 mic input

Started by loonloon January 3, 2006
Hi everyone! I am quite new to the TI C6711 DSK. Can someone please let me
know if the microphone input on the C6711 DSK is mono or stereo? Any
advice is gladly appreciated.



loonloon wrote:
> Hi everyone! I am quite new to the TI C6711 DSK. Can someone please let me > know if the microphone input on the C6711 DSK is mono or stereo? Any > advice is gladly appreciated.
Look at the connector. How many distinct terminals does it have? Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
"Jerry Avins" <jya@ieee.org> wrote in message
news:Ydydnap-c7i4CSfeRVn-jg@rcn.net...
> loonloon wrote: > > Hi everyone! I am quite new to the TI C6711 DSK. Can someone please let
me
> > know if the microphone input on the C6711 DSK is mono or stereo? Any > > advice is gladly appreciated. > > Look at the connector. How many distinct terminals does it have?
The 6711 DSK schematics show it as a mono connector, AC coupled with no bias. However, unlike line in, line out and speaker out, the number of connections isn't necessarily an indication of mono or stereo for mics: although the mic connector often has a screen, a ring and a tip, the screen is earth, the ring is dc bias via a ~2.2k resistor to 5V for an electret condenser mic, and the tip is the signal. So often mic connectors are mono despite looking stereo. To confuse matters, the TMS320C6713 DSK (16 Mb version) docs show the tip and ring are swapped from the above 'industry standard', but in fact the tip and ring are connected together with a DC bias to 2.5V. These connections on the '6713 DSK are not shown in the schematics for some reason. Cheers, Howard
Howard Long wrote:
> "Jerry Avins" <jya@ieee.org> wrote in message > news:Ydydnap-c7i4CSfeRVn-jg@rcn.net... > >>loonloon wrote: >> >>>Hi everyone! I am quite new to the TI C6711 DSK. Can someone please let > > me > >>>know if the microphone input on the C6711 DSK is mono or stereo? Any >>>advice is gladly appreciated. >> >>Look at the connector. How many distinct terminals does it have? > > > The 6711 DSK schematics show it as a mono connector, AC coupled with no > bias. > > However, unlike line in, line out and speaker out, the number of connections > isn't necessarily an indication of mono or stereo for mics: although the mic > connector often has a screen, a ring and a tip, the screen is earth, the > ring is dc bias via a ~2.2k resistor to 5V for an electret condenser mic, > and the tip is the signal. So often mic connectors are mono despite looking > stereo.
That's as may be, but given a mono connector, stereo seems unlikely.
> To confuse matters, the TMS320C6713 DSK (16 Mb version) docs show the tip > and ring are swapped from the above 'industry standard', but in fact the tip > and ring are connected together with a DC bias to 2.5V. These connections on > the '6713 DSK are not shown in the schematics for some reason.
The OP can also check the number of channels the codec has, even if he has to look it up via the type number. Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;
Hi Jerry

"Jerry Avins" <jya@ieee.org> wrote in message
news:0a6dndlkWaH9aSfenZ2dnUVZ_tSdnZ2d@rcn.net...

> >>Look at the connector. How many distinct terminals does it have?
> > However, unlike line in, line out and speaker out, the number of
connections
> > isn't necessarily an indication of mono or stereo for mics: although the
mic
> > connector often has a screen, a ring and a tip, the screen is earth, the > > ring is dc bias via a ~2.2k resistor to 5V for an electret condenser
mic,
> > and the tip is the signal. So often mic connectors are mono despite
looking
> > stereo. > > That's as may be, but given a mono connector, stereo seems unlikely.
I was just trying to explain that your suggestion of counting the number of distinct terminals is potentially misleading in that even if it did have three conductors it is usually not stereo in the mic department. Cheers, Howard