• Resolved

TS3A227E: TS3A227E switch from 3-pole to Standard (CTIA) mode

Part Number: TS3A227E

Hi,

I have a headset which is not properly working with the TS3A227E. Tip-to-Sleeve resistance is 1.46 kOhm and Tip-to-Ring2 is 18 Ohm. According to this post it should be a standard (CTIA) headset:

However, its only detected as 3-pole. I also managed to setup some resistors on a 4-pole plug for simulating a headset and I have similar problems. Although this setup will be most of the times be recognized as a standard (CTIA) headset, sometimes the TS3A227E states it is only a 3-pole.

What could be the problem?

Best regards, Thorben

  • Thorben,

    The post you referenced shows how the detection scheme works and that resistance between tip and Ring2/sleeve is what the audio jack IC uses to determine 3-pole or 4-pole. Since you measured a difference impedance between the tip and ring2/sleeve it should be detected as a 4 pole.

    Do you have the model of the headset that is being detected incorrectly?

    Which resistor values are being detected incorrectly?

    Can you quantify how many times you mean sometimes?

    How are you monitoring the TS3A227E to know if 3-pole or 4-pole is recognized by the part?

    Adam
  • In reply to Adam Torma:

    Dear Adam,
    thank you for your answer.

    Adam Torma

    Do you have the model of the headset that is being detected incorrectly?


    It's an "ISY IIE 1101 be" headset.

    Adam Torma

    Which resistor values are being detected incorrectly?


    I used 22 Ohms on the right and 22 Ohms on the left speaker channel. For the Mic I used 680 Ohms.

    Adam Torma

    Can you quantify how many times you mean sometimes?


    It's about 1 out of 10 times.

    Adam Torma

    How are you monitoring the TS3A227E to know if 3-pole or 4-pole is recognized by the part?


    I'm reading register 0x0B and returns 0x09 for 3-pole and should return 0x0C wich it does most of the time but not always.
    Register 0x4 is set to 0x27 (de-bounce time = 2 seconds).

    Regards, Thorben

  • In reply to Thorben Vornholz:

    Thorben,

    My first thought is that internal ADC resolution might be at the edge of detecting the difference in the impedance. I have confirmed that 1.46 kOhm and Tip-to-Ring2 is 18 Ohm are well within the ADC resolution and should not be an issue. The 680 and 22 ohms is closer to the limit of the ADC capability but should not be an issue either.

    The next thought is that there is timing issue with the detection sequence and that it is finishing before the headset in fully inserted but 2 second debounce should take care of that.
    How are you initiating the detection sequence in your testing? Are you using the automatic detection and pluging in and out the headset multiple times? Are you using the I2C commands to initiate the detection algorithm?

    The third thought is that the connection of the headset to the jack is not great. If there is high impedance >~1.5k on both tip to sleeve and tip to ring2 the TS3A227E would detect as a 3-pole because the ADC would max out and the device will declare the impedance equal to each other.

    Do you have a picture of your board or set up?

    Thank you,
    Adam
  • In reply to Adam Torma:

    Adam Torma

    How are you initiating the detection sequence in your testing?



    I primarly tried auto detection for all my test by pluging in and out but I also tried the procedure on page 22 (sequence 2) for manual triggering.

    Adam Torma

    The third thought is that the connection of the headset to the jack is not great.


    I think, I can figure that out within one or two days.

    Adam Torma

    Do you have a picture of your board or set up?


    Please find the schematic in the image attached to this post. It also includes another IC which caused some problems. See this post for details:

    e2e.ti.com/.../663072

    Regards,
    Thorben

  • In reply to Thorben Vornholz:

    Thorben,

    In the attached schematic I see you are properly using the SJ-435107RS isolating switch on pins 5 and 6 of X1502.  When a headset is inserted into X1502, the pull down resistor on pin 6 will connect and pull down the TS3A227E det_trigger pin to initiate the detection sequence.  Using the 2 second debounce setting should account for any issues with slow plugging an audio jack.

    With the 4-pole headset permanently plugged into the audio jack and you manual trigger the detection sequence does this always detect as a 4-pole headset? 

    How many times does this incorrectly detect as a 3-pole? 

    When it incorrectly detects as a 3-pole, without doing another manual detection, does reading 0x0B again fix the issue or does register 0x0B always return 3-pole once it incorrectly detects?  I'm trying to see if maybe you are reading the register before the detection is complete and the 0x0B register is updated.

    Thank you,

    Adam

     

      

  • In reply to Adam Torma:

    Dear Adam,

    good to hear that the hardware looks fine.

    I tried a lot of different things to track it down a bit further. It somehow seams to be a problem with the 4-pole plug of the headset. Plugging the headset in an short selfmade extension cable and connecting this to my device doesn't cause any problems. Besides that I also tried your approach of manually triggering the detection sequence. See the attached scripts for details.

    man_trigger.sh is basically sequence 2 on page 22 of the manual and I used it as well as it is intended by having nothing plugged in at first and pluggin in the headset after event 2. I also used it while leaving the headset attached and ran the script several times.

    I've done the same for the re_trigger.sh script and it looks like that, once one type is detected, it does not change by triggering the detection again. Only unplugging and plugging it back again changes the type.

    Adam Torma

    How many times does this incorrectly detect as a 3-pole?


    Like I said, once it's plugged in, none of the scripts can change the 0x0B status to something else.

    Regards, Thorben

    man_trigger.txt

    re_trigger.txt

  • In reply to Thorben Vornholz:

    Thorben,

    Do I understand you correctly that you think the headset is causing your issue and that the TS3A225E is behaving as expected?

    You confirmed this by creating your own extension that you don't have any issue?

    I have gotten in samples of this device and put it on a board and can try and recreate the problem if you are still having issues with the IC.

    Thank you,
    Adam
  • In reply to Adam Torma:

    Dear Adam,

    it looked like the headset is causing trouble. Today, I had my setup disassembled in between, I saw 3-4 false detections even with the extension cable. It's strange, because it doesn't add that much of extra impedance to the setup. So I wouldn't blame the headset for the issue since I've now seen the issue with the extension cable as well and also some customers complaining about that issue with their smartphone headsets.

    In previous test I noticed some significant crosstalk during simultaneous playback and recording with this headset. By adding the extension cable, the crosstalk increases by ~13 dB because the wires are not bundled. Is it possible that this somehow improves the detection mechanism?

    Please try to reproduce the error on your side.

    Regards, Thorben

  • In reply to Adam Torma:

    Dear Adam,

    have you been able to reproduce the error?

    Regards, Thorben

  • In reply to Adam Torma:

    Hi Adam,

    if you're unable to reproduce it, could you please tell me, how I can change the detection state of TS3A227E via software/register settings? Refering to SCDA014 it should be possible to change the state from 3-pole to 4-pole or from OMTP to CTIA but I don't know how. Please tell me the exact register settings I have to set because all of my previous attempts failed.

    Regards, Thorben