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TS3A227E: DET_TRIGGER Unused

JDJ
Expert 4486 points
Part Number: TS3A227E
Other Parts Discussed in Thread: TIDA-00565,

Hello, 

We are trying to detect periodically, do you have any recommendations? The system will be asleep so unable to send an I2C command. 

One option, we are thinking of using a timer and fet on the MICBIAS pin and utilizing the key press functionality to trigger a detect. 

Another option would be to use a digital pot and trying to change the value periodically. 

Have you seen either of these implemented? 

Since you need a falling edge for det_trigger, can we ground this if we are trying to periodically detect? 

Thanks!

  • 0
    TI__Mastermind 35638 points

    JDJ,


    What are you trying to detect exactly? My understanding here is that the entire system will be asleep and you want to check at some periodic interval whether there's a trigger event (mic present) while the device is in sleep mode and wake up the system when the even is triggered. However, the device will wake up from sleep mode whenever an accessory is inserted and doesn't need I2C communication to wake it up.
    Is this a 4-pole accessory? Unless i'm misunderstanding what's happening here, could you use the status of ~mic_present or ~INT to see when a detection has been made and wake the system up?

    If i've missed the mark here, could you share a diagram or schematic of some sort to better explain what you're attempting to do here? 

    Thanks,
    Rami

  • 0 in reply to Rami Mooti1
    TI__Expert 4486 points

    I found TIDA-00565, and from the user guide you can still automatically wake up and detect a microphone through the USB type C connector. Is this correct? 

    We are trying to implement something very similar to that reference design. 

  • 0 in reply to JDJ
    TI__Mastermind 35638 points

    JDJ,

    Looks like you'll need a GPIO to pull down the DET_TRIGGER pin to actually begin the detection sequence. Otherwise the TIP pin won't register and you won't actually get a detection. 

    Here's a good thread on this that may be of some help :

    Further more this blog may be of some interest as well:

    USB Type-C audio: Do I need to buy a new pair of headphones?
    For a recent trip to New Orleans, I invested in a quality pair of noise cancelling headphones to help me drown out the chatter. I am thrilled with my new purchase but I’m concerned I won’t be able to use…
    By in Technical articles > Analog

    Thanks,
    Rami

  • 0 in reply to Rami Mooti1
    TI__Expert 4486 points

    Why won't the TIP pin register and get a detection?

    In the reference design guide it says the TS3a227E will automatically detect but to clarify it still need a gpio or I2C signal to start the detect?

    "The TS3A227E is used specifically to automatically detect and orient the MIC and GND signals of the 3.5 mm jack to support the function described in the USB Type-C standard above"

    Could you connect a timer directly to DET_trigger to periodically detect? 

  • 0 in reply to JDJ
    TI__Mastermind 35638 points

    JDJ,

    My apologies, I missed the spot on this one. When thinking about the pin setup i was thinking about the direct connection from USB-C to the switch and bypassed the TIDA-00565.

    You'll be fine with the TS3A227E using the TIDA-00565 reference design. It will automatically detect. Does this remove your need for the DET_TRIGGER to be periodically detected as it will be automatically whenever inserted? 
    My feelings are that with the automatic detection you won't need periodic detection but in case, i'll still tackle the point. Using a timer to periodically detect may work depending on what you had in mind. The DET_TRIGGER pin simply initiates the detection sequence. When a headset is inserted into the jack the mechanical switch will close the connection from DET_TRIGGER to TIP which send the trigger from high to low to start the detection sequence to determine the audio jack type and complete the detection. By connecting a timer, if sounds like you're aiming to send high and low signals in periodically which will just be like starting a detection sequences continuously. All you would really be doing there is initializing fake detections.

    Hope this helps,
    Rami Mooti