TUSB4041I: 24MHZ clock output is abnormal

Hi,

The crystal will stop when the hub is suspended or not connected to a host.

If a host is connected to the hub, but there are no downstream devices connected the host will often suspend the hub.

Are the hub / downstream device enumerating correctly or not?

Can you send a clock waveform? Does the waveform improve if you replace the 33ohm resistor with 0ohm and change the crystal loading capacitor.

Thanks

David

Hi David,

Today we did a few tests:

1. At present, we will fly the uplink USB2.0 interface out, and the mouse connection is OK.

2, clock 24MHZ is the drawing of FB14 welding, and then output.

3. 1pcs EEPROM is externally connected on the drawing, the model is at24c04bn-sh. Does this EEPROM need burning program?

4. The power supply has been adjusted according to the chip data, 3.3V>>1.1V

5. At present, some IO status errors are suspected, please help to check the schematic diagram

Thank you very much!

Hi,

Is SMBUSz being pulled high or low? if the TUSB4041 has SDA/SCL pulled high and a blank EEPROM attached, it will automatically enter programming mode and stay there until the EEPROM is programmed.  While in programming mode, the hub will not function as a hub.

You can leave SMBUSz as NC if external interface is not required. 

Looking at the schematic, you do not need the common mode choke on the hub upstream port.

Thanks

David

Hi David,

I try to leave SMBUSz as NC, but the HUB is also not work. Now the EEPROM is a blank EEPROM.

Does the hub chip need firmware when it works?Can you send a firmware? Let's burn it to EEPROM to try.

the common mode choke on the hub upstream port, I don't think it will cause this hub to not work，So I didn't delete it.

Thanks.

Hi,

The EEPROM is optional, the hub will work without the EEPROM.

In your earlier message, you said the mouse connection is ok, so it looks like the hub is correctly being enumerated, is this correct?

Can you please send a picture of the clock waveform and have you tried to change the 33ohm to 0ohm on the crystal input and output?

Thanks

David

Hi David,

1. I'm sorry, maybe I didn't make it clear. Currently, I can't connect the mouse either. I've been synchronising the test and the waveform will be sent out.At the moment it has a waveform at 33 ohm.

2. Whether EEPROM needs driver, as I have seen doing this related post, https://e2e.ti.com/support/interface-group/interface/f/interface-forum/622318/tusb4041papevm-were-can-i-get-the-microsoft-windows-based-eeprom-utility-and-windows-drivers-for-the-tusb4041-eeprom-programming-interface-with-vid-0451-and-pid-80ff 

3. Is there any documentation about TUSB4041 design and debugging steps?

Many thanks!

Hi David,

The problem of this event has been found and solved. Thank you very much. I will close this event.

Wish a happy Mid-Autumn Festival in advance!

Hi,

Awesome. Thanks for the update and I am glad you are able to solve the issue. Any chance you can share the root cause of the issue?

Wish you a Happy Mid-Autumn Festive as well!

David

Hi,

Thanks for the detailed explanation. Again, I am glad you are able to solve your issue.

David