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TS3A227E: couldn't detect keys

user5328040
Prodigy 30 points
Part Number: TS3A227E

Hi,

We now use the TS3A227E as a Bluetooth receiver to read the register data through the IIC. There are several problems that  I hope you can help me.

1, there are some problems with the current polarity detection of headphones, 4-pole headphones will be identified as 3-pole headphones;

2, the keys of the headphones can not be identified, read the 0X02 register through IIC, the value of the register is still 0.

And i wanna konw that does TS3A227E need host to initialize it ?

Best Regards,
Frank

  • 0
    TI__Mastermind 22965 points
    Hi Frank,
    One of our applications engineers will get back to you shortly. -- Are the two issues you described intermittent or occur consistently?
  • 0 in reply to Ravi Singh
    Prodigy 30 points
    Hi Ravi,

    It's occur consistently!

    After power on and then plugging in the headphones, read the value of the register through the IIC, it is found that the polarity of the headphones is 3-poles and the headphones keys has no effect (the value of the 0X02 register is not changed).

    Plugging in the headphones before power on , and then read the value of the register through the IIC, can correctly detected the 4-poles headphones, but the keys of the headphones can not be identified.

    I have read the datasheet , it says that the polarity of headphones is automatically detected.

    Does software affect polarity detection and keys?

    Best Regards,
    Frank
  • 0 in reply to user5328040
    TI__Expert 6395 points

    Hello Frank,

    Can you measure the resistance of the headset you are using in your testing:

    • TIP pin to RING2
    • TIP pin to SLEEVE

    In addition can you provide waveforms of the key presses?  You should be able to monitor the microphone line and see the voltage drop when a key is pressed.

    Regards,

    Andrew

  • 0 in reply to Andrew_Mason
    Prodigy 30 points

    Hi Andrew,

    I tested the voltage between two pins in various situations.

    resistance(Ω) No power supply (no insert) have power supply(no insert) power off(have insert) power on(have insert) power on(remove and then insert)
    • TIP pin to RING2
    		 10K 144 24 10 111
    • TIP pin to SLEEVE
    		 10K 144 124 6.1K 111

    is this right ?

    Best Regards!

    Frank

  • 0 in reply to user5328040
    TI__Expert 6395 points

    Hello Frank,

    If I understand the above chart correctly, the resistance of the headset changes depending on the power of the headset and whether it is inserted. Is this correct?

    Based on the above chart the only time a 4-pole would be detected would by the power on (have insert) case.

    Regards,
    Andrew