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TUSB320LAI for Audio Accessary Mode

Lina Lian
Intellectual 1570 points
Other Parts Discussed in Thread: TUSB320LAI, TUSB320

All,

When connect 1.2KOhm to GND on both CC pin, TUSB320Lai should detect it as audio accessary. How about TUSB320LAI next action? Will it take ID pin low, and supply 500mA over VBUS? Based on our spec as below, it seems that should support passive audio adaptor or charger audio adaptor, what’s the difference? Customer hope when TUSB320LAI detect audio accessary, will not provide VBUS.

Thanks a lot. 

BR,

Lina

  • 0
    TI__Guru* 76130 points
    Hello,
    we have assigned a support engineer to work on this.
    Regards
  • 0
    TI__Mastermind 36085 points
    Hello,

    The customer can use the audio accessory attach state in the status registers or the OUT3 during GPIO mode to activate VBUS, our device also supports to charge thru accessory (which happens when the TUSB320 detects the accessory and VBUS). But for audio accessory the TUSB320LAI won't drive ID pin to LOW.

    Regards,
    Diego.
  • 0 in reply to Diego Cortes
    TI__Intellectual 1570 points

    Diego,

    Thanks a lot for your kindly help. According to TUSB320LAI datasheet, it seems that it can support 2 kinds of audio accessory, one is Passive Audio Adapter, and the other is Charge Through Audio Adapter. What's the difference for this two type while TUSB320LAI for recognition? 

    Based on your explanation, my understanding is:

    1. For Passive Audio Adapter, the TUSB320 device must detect a resistance < Ra on both of the CC pins, but no power supply over VBUS. Then can read register 0x08, bit3-1 is 100, we can know that it's in Passive Audio Adapter. In this mode, ID pin will not drive LOW, and VBUS will also not provide power supply to external.  Right?

    Diego Cortes said:
    activate VBUS

    What' your meaning of "activate VBUS" ? in this mode, customer can also have VBUS provide power supply to external? How to activate VBUS? 

    2. How about Charge Through Audio Adapter? TUSB320 device must detect a resistance < Ra on both of the CC pins, while also have power supply over VBUS? Then can read register 0x08, bit3-1 is 101? 

    Would you please give a hand to description it more clearly? Thanks a lot.

    BR,

    Lina

     

  • 0 in reply to Lina Lian
    TI__Mastermind 36085 points

    Hello Lina,

        You are correct, the VBUS presence determines whether the audio accessory is active or passive. As I mentioned before, the TUSB320LAI notifies when an audio accessory has been connected by means of the status registers or OUT3, but please disregard my comment regarding to activate VBUS since it should be needed for passive audio accessories.


        Regarding your question about charge through audio adapter, your understanding is correct, the device must detect a resistance < Ra on both of the CC pins, while also have power supply over VBUS.

    Regards,

    Diego.


       

  • 0 in reply to Diego Cortes
    TI__Intellectual 1570 points
    Diego,
    Thanks a lot for your kindly help. I really appreciate it. :)

    BR,
    Lina
  • 0 in reply to Diego Cortes
    Prodigy 10 points

    Hello Diego，

              I have a question on this.

              Is the VBUS  provided by TUSB320  or  detected by TUSB320 ?

              I have a TUSB320 EVM , I reperesent  the resistance < Ra on  both of the CC pins, then provide the VBUS for TUSB320 , but the register doesn't work rightly.

              Could you help me ?

    Regards,

    Haibin.

  • 0 in reply to Gang Liu23
    TI__Mastermind 36085 points

    Hello Haibin,


         The TUSB320 has two roles; when in DFP (or RDP acting as a source) mode, the TUSB320 detects valid UFP terminations and asserts the ID pin to LOW and updates its internal registers, both actions can be used as a trigger to activate the VBUS power switch. On the other hand, when the device is in UFP (or DRP acting as a sink), the TUSB320 detects the DFP terminations and VBUS, afterward both detections, the deivce updates its internal registers or GPIOS to advertise the connection state.

    According to your issue description, the problem is with the audio accessory detection. For this specific case both Ra terminations must be connected at the same time, for manual testing I recomend to use two resistors connected together to a common switch or jumper to GND,in this way tou can connect first the resistors to the CC pins and then connect the GND terminal. If the device is in UFP mode, then you must provide VBUS after connecting both Ra terminations.

    Regards,

    Diego.