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PCM2912A - XP does not retain microphone level setting after USB unplugged

Terence Brennan
Prodigy 30 points
Other Parts Discussed in Thread: PCM2912A

We need to have the PCM2912A microphone level setting retained after it is unplugged/replugged.  The Set-Up Guide (SBAU141, pg 26)  for the demo board says:

"Microphone Volume Windows for Record Volume Setting (Windows XP)  Set the microphone volume and the recording mute level from –12 dB to +30 dB, as shown in Figure 3-11. The initial volume setting upon installation is approximately +8 dB. After this process is complete, the system volume setting for each component is maintained even if EVM is plugged in/out."

This does not happen on our XP computer.  Yet the same computer does permanently retain the microphone settings for other similar audio converters.  Testing the PCM2912A, the setting almost always resets back to a default setting of about 7% of full scale.   This PC has saved the setting a few times -- but most often goes back to the default.

However the PCM2912A settings are retained on a different PC with Win7.   And another XP machine seems to retain the settings (but time will tell).

We are designing a device which will require an initial calibrated setting to be reliably retained.  

Any suggestions or help concerning this would be greatly appreciated.   

-Terence-

  • 0
    TI__Genius 16270 points

    Terence,

    I am able to lock the volume setting using a WinXP computer as well.  Can you provide any more info about the computer that is having trouble?  This functionality should work for XP or Win7.

  • 0 in reply to Patrick Galvin
    Prodigy 30 points

    Patrick,

    I understand you can get a manual microphone setting to lock on your XP computer, and that is the way it is supposed to work.  We can do that too, on one XP computer -  but not on two others.     

    We observe this problem on two different IBM laptops.  One is running XP(SP2) and the other is XP(SP3).  Both of these computers exhibit the same behavior, although they have different builds of the Windows Audio Mixer.  

    When the PCM2912A is initially plugged in to any Windows computer, it apparently sets the microphone level to 7% of full scale.   So we plug it in.  Then, for example, we adjust the slider 50%.  We unplug the device.  When we plug it back in we find the setting is reset to 7%, as though the device was being plugged in for the first time.

    On the other hand, we have an desktop XP(SP3) computer (which incidentally has the same version of the Windows Audio as the SP3 laptop above).  But this XP computer always retains our manual setting of the microphone control.  It has never reset back to the 7% level.  And that same desktop computer, when it is running Win7 with a different hard drive, also retains our manual settings.

    Here are the Volume Control versions for each XP computer:

    XP(SP2) laptop:  Volume Control Version 5.1(Build 2600.xpsp_sp_gdr.070227-2254:Service Pack 2)

    XP(SP3) laptop:  Volume Control Version 5.1(Build 2600.xpsp.080413-2111:Service Pack 3)

    XP(SP3) desktop: Master Volume Version 5.1(Build 2600.xpsp.080413-2111:Service Pack 3) 

    So our problem is this:

    (1) If the behavior was consistent we could probably work around it by using an external adjustment, a potentiometer.  

    (2) If the setting were reliably retained in the PC, then we could trust that for our calibrated adjustment.  

    (3) But if the PC setting is sometimes set by the device, but not always, then we have no way to rely upon any setting, internal or external.  

    -Terence-

      

  • 0 in reply to Terence Brennan
    Expert 1520 points

    Dear Terence Brennan

    My customer is considering to use the PCM2912A for USB Audio Earset.

    I would like to ask you to clear the supporting OS and USB Class in PCM2912A.

    1. Is this device support these OS? Window 2000, Window Xp, Window VISTA, Window 7, Window 8, Window NT.

    2. Is this device support Backward compatibility for USB 1.x ~USB2.0?

     

    Thanks and Best Regards

  • 0 in reply to Jin Kyung Han
    TI__Genius 16270 points

    Jin,

    1)  This device is plug-and-play for any OS that supports USB Audio Class.  Furthermore compliance testing has been done for most Microsoft OS, except for Win8 thus far.  Although there should be no changes between Win8 and Win7 from an audio standpoint.

    2)  For Win8/USB 2.0 applications that have a jack, there are detection requirements from a system standpoint that the device cannot support just by itself.  So if the application has a jack some detection circuitry will also be needed to report status such as "plugged, unplugged" etc.  This device is able to support 1.1 speed transfers ore 2.0 speed transfers, so that should be no problem.

  • 0 in reply to Patrick Galvin
    Expert 1520 points

    Dear Patrick

    Thank you for giving me the answer for questions.

    Regards