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TUSB320LAI: How to set up the TUSB320LAI to charge the iPAD.

Pakho
Prodigy 95 points
Part Number: TUSB320LAI
Other Parts Discussed in Thread: TUSB320

Tool/software:

Hi TI team,

I've set TUSB320LAI to I2C mode. Enable 3A current output. It can now charge the phone, but not the 3A, and it doesn't charge the iPad.

  • 0
    Prodigy 95 points

    Design as below.

  • 0 in reply to Pakho
    TI__Prodigy 420 points

    Hi Pakho, 

    For TUSB320 device to advertise 3A, TUSB320 Vdd has to be 3.5V or greater. Assuming all steps to configure the CSR registers using the I2C mode is correct, it is likely that the device is not given the correct Vdd to advertise 3A based on the design you provided. 

    Thanks,

    J

  • 0 in reply to J
    Prodigy 95 points

    Hi J,

    I tried increasing the VDD to 4.7v. It still doesn't work.

    Here's my setup. Any questions? When DFP mode is connected, I set the current mode to high.

  • 0 in reply to Pakho
    TI__Prodigy 420 points

    Hi Pakho,

    Based on the design you sent, I am wondering if SCL and SDA are powered with 3.3v and pull-up resistor.

    On the software side, is set_current_mode() doing the similar operation of i2c_read, modify, and write in the setup_tusb320lai()?

    If so, I wonder if your code is doing i2c RMW operation too fast. Would you be able to probe INT_N pin to see if it is pulled low when you run your code?

    Best,
    J

  • 0 in reply to J
    Prodigy 95 points

    Hi J,

    The answers are as follows:

    Based on the design you sent, I am wondering if SCL and SDA are powered with 3.3v and pull-up resistor.

    -> Yes, SCL and SDA are powered with 3.3v. And current pull-up resistor is 1.8K.

    On the software side, is set_current_mode() doing the similar operation of i2c_read, modify, and write in the setup_tusb320lai()?

    -> Yes. Details as below.



    If so, I wonder if your code is doing i2c RMW operation too fast. Would you be able to probe INT_N pin to see if it is pulled low when you run your code?

    -> I will try add 1ms delay after every I2C operation.

    -> What you mean is that all I2C operations require INT_N pin to be kept low?

    Thanks,

    Pakho

  • 0 in reply to Pakho
    TI__Prodigy 420 points

    Hi Pakho,

    -> What you mean is that all I2C operations require INT_N pin to be kept low?

    I meant that INT_N is an active low interrupt signal so it is supposed to go low when there are changes being made in the I2C registers. Therefore, probing this pin while you are running your code will give an indication if the code is making any changes to the I2C registers. 

    Best, 
    J

  • 0 in reply to J
    Prodigy 95 points

    Okay, currently all I2C operations are after receiving the INT_N triggered. 

    What is the different between "Debug accessory when the TUSB320 device is connected as a DFP." and "DFP "?

  • 0 in reply to Pakho
    TI__Prodigy 420 points

    Hi Pakho,

    DFP is the regular downstream facing port state that TUSB320LAI can configure when used as a source according to the Type-C specifications. 

    "Debug accessory when the TUSB320 device is connected as a DFP" is the debug state. This state is an additional debug state for testing. More information about the debug can be found in Section 7.3.3.2, or below.

    ]

    Best,
    J