TUSB2046B: TUSB2046 Clock halted after ~7mS, resumes 100mS later "Device Not Recognized"

tony tumminaro

Part Number: TUSB2046B

Hello,

Having an issue with the TUSB2046B. I've tried multiple reset circuit combinations, and I can't seem to get windows to recognize the chip when plugged in (It always says"Device Not Recognized"). I have one downstream device connected, all open downstream devices currently have a 15K pulldown.

No matter what reset RC combo I use, the clock starts and runs for 6mS. At that time the clock stops for 100mS, resumes for another 650mS, and then stops again.

My timing circuit is currently a 15K and 100nF, which produce the output shown below.

Is there something obvious I'm missing? Any help or advice would be appreciated as I've burned quite a few hours toying with the reset and I'm always getting the same results.

Thank you in advance.

over 6 years ago

0 JMMN over 6 years ago

TI__Guru 60870 points

Hi Tony,

I don't see the 1.5K pullup on the upstream port DP line. Did I miss it in the schematic? Also, all the downstream ports will need 15K pulldowns.\

Regards,
JMMN

0 tony tumminaro over 6 years ago in reply to JMMN

Prodigy 110 points

R127 is the 1.5K pullup on DP line. 15K pulldowns are also on the schematic on all downstream ports, with the exception of R106 and R107 which are listed on the schematic as DNP. I have 15K pulldowns in those locations currently.

Apologies for the snippets of the schematic, there are items I must redact.

0 David (ASIC) Liu over 6 years ago in reply to tony tumminaro

TI__Guru**** 157496 points

Hi Tony

Do you have the TUSB2046B powered up first, and then plugged into the host? Or plugged into the host, and then power up the TUSB2046B? Would you please send me a capture of VBUS, 3.3V, DP, and DM when you plugged TUSB2046B into the host?

Have you also tried to plug in TUSB46B without any downstream devices connected?

Thanks
David

0 JMMN over 6 years ago in reply to David (ASIC) Liu

TI__Guru 60870 points

In addition to the data David requested, can you check if the SUSPEND pin is going high?

0 tony tumminaro over 6 years ago in reply to David (ASIC) Liu

Prodigy 110 points

I appreciate the responses, but I seem to have corrected the issue. I had a bad 22 ohm resistor on DM0. I was seeing data on it, but the shape must have been sloppy. Replacing the resistor has the hub up and working.

Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

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TUSB2046B: TUSB2046 Clock halted after ~7mS, resumes 100mS later "Device Not Recognized"