• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 33 subscribers
  • Views 411 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TUSB8041: Serial No. setting

Taketo Sato
Genius 10315 points
Part Number: TUSB8041
Other Parts Discussed in Thread: TUSB8040

Hello team,

TUSB8041 connects to USB device on downstream port and Windows PC on upstream port.

I faced an issue that COM port number assigned on Windows PC changes if I change a board to another. This phenomenon wasn’t observed when I used TUSB8040.

 

I suspect it may be because serial number of TUSB8041 changes when changing a board, then Windows misunderstands that other device is connected and assign different COM port number.

Looking at TUSB8040 datasheet and TUSB8041 datasheet, I found below differences regarding serial number setting.

TUSB8040: customSernum=1, SerNumStringLen=0

TUSB8041: customSernum=0, SerNumStringLen=24

SerNumStringLen is set to 0 as default on TUSB8040, so serial number is not supported. Therefore I guess COM port number didn’t change with TUSB8040 when changing boards.

 

 

I have questions as below.

Is above my guess correct? Or is there any other possible cause?

Can I think TUSB8041 become equivalent setting with TUSB8040 regarding serial number if we set customSernum=1 and SerNumStringLen=0 on TUSB8041?

Best regards,
Taketo Sato

  • 0
    TI__Guru 60870 points

    Hi Sato-san,

    Yes, you can disable the serial number reporting using an EEPROM  or SMBUS host with the TUSB8041 or later devices.  The original TUSB8040 silicon disabled serial number reporting.  We enabled it by default on the USB 2.0 portion of the later hubs since we found some drivers required it.

    Regards,

    JMMN