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TUSB8042A: Asking for TUSB8042 design review

SHH
Mastermind 32196 points
Other Parts Discussed in Thread: TUSB8042

Hi Sir,

My customer would like design TUSB8042. please refer to design material here. 

password: "ti"
https://txn.box.com/s/9e2p95jcjbkrb43ffy578h01lorsjdqn

the currently PCB is back. however, the TUSB8042 is not recognized on the Windows.

Would you please review the schematic and let us know if any issue?

1. USB_VBUS is an input to the hub and should only be high when an active hub is connected. What is the pin 48 voltage?
     >>0.5V
2. Do you place the EERPOM on the board? If yes, please remove the EEPROM.
     No EEPROM on the board
3. Where the TUSB8042 upstream connect to? PCIE? How do you know this is hub failed?
     >>Connect to Nvidia Jetson Xavier NX USB interface, need to confirm that Hub connection and setting is correct.
4. Adding a pullup on the PWRCTL lines enables battery charging on that port. What is the pin 35 and pin 36 voltage?
     >>3.3V
5. The capacitor on GRSTz may need to increase to 2 uF if the power on ramp times are slow. What is GRST pin 50 voltage?
     >>3.195V

power and GRST pin waveform

is the setting here right?


BR,
SHH

  • 0
    TI__Guru 60870 points

    Hi SHH,

    It looks like the hub has SMBUS mode enabled.  Please remove R248.  If the hub is in SMBUS mode, it will not connect until a SMBUS host configures it.  If no EEPROM or SMBUS is used, SMBUSz should be high or left to float (internal pullup).

    Regards,

    JMMN

  • 0 in reply to JMMN
    TI__Mastermind 32196 points

    HI JMMN,

    Remove R248, hub can be recognized in Windows.

    Customer has another issue about PWRON_BATEN12 (Pin35/36).

    Customer would like to know any thing need to modify for these two pin.

    PWRON_BATEN12 (Pin35/36) always kept at low.

    Please kindly let me know your comment.

    BR,

    SHH

  • 0 in reply to SHH
    TI__Guru 60870 points

    Hi SHH,

    Can the customer confirm that: there is a pullup on PWRON_BATEN12 that enables battery charging, PWRCTL_POL is pulled up (power controls are active high) and that the OVERCUR12 pins are high (no overcurrent event)?  If battery charging is enabled the PWRON_BATEN12 line should be high when USB-VBUS is low and then toggle low when the host is connected and then go high again when the host enables downstream port power.

    Regards,

    JMMN