AIC34 EVM Headset Detection.

HI Mushtaq,

I am not sure if the GUI will recognize changes in the headset detection status. The only way to determine the status is to manually read the status registers. You can use the GUI to go to the command line tab, then read the registers by typing at the command line. The result will be seen in the register list to the right. 

Hi:

What I am observing is that once a headset has been detected, the detection flag, bit 4 of register 14 remains set, irrespective of whether the headset is plugged in or not.

Shouldn't the flag get cleared when the headset is removed, and set when plugged in?

Looks like I am missing something.

Could you please help?

Thanks a lot!

Cheers,

Mushtaq

Hi:

What I further observed is that even if I clear the headset detection flag in register 14, on reading that register the bit remains set.

I don't know what I am missing. Is there some particular sequence in which this has to be done?

Thanks a lot!

Cheers,

Mushtaq

Yes, assuming everything is correct in the software and hardware, reading this bit should clear it.

There is a detailed app note on this feature here:

http://www.ti.com/lit/an/slaa454/slaa454.pdf

Sir:

Reading the bit is not clearing the flag!. Once set it remains set, irrespective of whether I read the register or write a zero to it. It gets cleared if I disable headset detection; however, if I enable the flag goes back to one, even though the headset if not plugged!

Do you have a script that works for you which I can try here?

Thanks a lot!

Cheers,

Mushtaq

You can't write a 0 since it is a read only register bit. If the hardware conditions shown in the app note are met, the flag should clear once read. there is no required script. You just need to enable the feature. Next is a hardware requirement that the voltages at mic det are met to insure that the correct reading are obtained. Be sure to check the voltage at the mic det pin.

Sir:

I have tried three different headsets, and headset detection fails on all three!

This is your EVM. I haven't made any changes to the hardware. It should work, but it doesn't.

Thanks a lot!

Cheers,

Mushtaq

Hi Mushtaq,

It all comes down to the voltage at the Mic Det Pin. You will see on the schematic for the AIC34 EVM, that it is not set up to do headset detection. It is only set up to detect a mic in the Mic Jack. The data sheet and the app note that I linked show how to set up many different types of jack depending on what will be detected. The EVM has one possible connection. Also, with the EVM it is necessary to have the on-board mics disconnected or it will always show the same status.

Sir:

I went through the applicatio note that you had sent. It is clear from those how headset detection works. One needs MICDET to do so.

I also looked at the schematic for the AIC34EVM. In the AIC34EVM MICDET is actually used for the external microphone (J6 -- MIC3R/L). It is not available for detecting a headset plugged into the headset jack  (J7). In other words, if one plugs a headset into the headset jack J7 of the AIC34EVM, it cannot be detected. However, plugging/unplugging an external microphone from jack J6 can be detected.

So using the AIC34 EVM one cannot verify the headset detection feature of the AIC34?

Thanks a lot!

Cheers,

Mushtaq