TUSB2046I: TUSB2046 Device Descriptor Failed

Tyler Williams

Part Number: TUSB2046I

TUSB2046I is not being enumerated by the PC. I have changed the connection to RESET to a PWRGOOD connection on the LDO with a 10K pullup. I have moded the board with 10k pullups to 3.3V as well. The DP line to the upstream part now has a 15K pullup resistor but the PC is still giving a device descriptor failed message. All downstream ports are not powered I assume because the TUSB2046 has not successfully connected to the PC. Does anyone have any suggestions as to why the PC would not recognize the hub device?

over 1 year ago

0 Brian Zhou over 1 year ago

TI__Guru*** 144915 points

Hi Tyler:

Pull up on DP0 should be 1.5k, not 15k.

Regards

Brian

0 Tyler Williams over 1 year ago

Prodigy 10 points

Brian,

That was a typo, I have a 1.5k pullup on DP0.

0 Brian Zhou over 1 year ago in reply to Tyler Williams

TI__Guru*** 144915 points

Can you send PDF file, I can't see schematic clearly.

Regards

Brian

0 Brian Zhou over 1 year ago in reply to Brian Zhou

TI__Guru*** 144915 points

Can you take waveform for VCC,RESET and Crystal output?

Regards

Brian

0 Tyler Williams over 1 year ago in reply to Brian Zhou

Prodigy 10 points

Here is a picture of VCC and Reset. When I probe the crystal I am not seeing anything, could this be because the probe is causing issues? I have also attached a PDF of the schematic

0385.USB Hub Schematic.pdf

0 Brian Zhou over 1 year ago in reply to Tyler Williams

TI__Guru*** 144915 points

it could be the issue if crystal is not oscillating. I will review the schematic.

Regards

brian

0 Tyler Williams over 1 year ago in reply to Brian Zhou

Prodigy 10 points

Brian,

I have not had any luck with the crystal, but I did take a look at the device descriptor report in Windows. The device is not sending any data to the PC in the descriptor section. Please see below:

0 Brian Zhou over 1 year ago in reply to Tyler Williams

TI__Guru*** 144915 points

Can you try with R10 with 1.5k ohm?

Regards

brian

0 Tyler Williams over 1 year ago in reply to Brian Zhou

Prodigy 10 points

Brian, I gave that a try this morning with no luck. I have ordered an MEMS oscillator to try in place of the crystal next week. I suspect the crystal is not working correctly.

0 Brian Zhou over 1 year ago in reply to Tyler Williams

TI__Guru*** 144915 points

ok, let's wait for your new crystal.

Regards

brian

0 Brian Zhou over 1 year ago in reply to Brian Zhou

TI__Guru*** 144915 points

any update?

0 Tyler Williams over 1 year ago in reply to Brian Zhou

Prodigy 10 points

Hi Brian,

I was finally able to deadbug a MEMS oscillator onto the board and it worked great (along with the other mods). I think the routing for the xtal was not optimal and that caused the issue.

Thanks for reviewing this.

Interface

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TUSB2046I: TUSB2046 Device Descriptor Failed