TUSB2077A: Device Not Recognized / Crystal Not Oscillating

burak sakaci

Part Number: TUSB2077A

Hi All,

I have designed the usb hub schematic using TUSB2077A chip (As a reference I used the scheme of the development board.) 0841.USB_HUB.pdf

When i attached device to pc it shows as device not recognized and in windows device manager it shows as unknown device. And fail led is active.

Additionally reset pin is ok. ( I measured 3V3 at pin6 - reset pin) And I use scope for crystal pin. Crystal not oscillating. I tried all possible methods for MODE, EXTMEM,BUSPWR and EEDATA pins.

I searched on the forum all possible method tried almost every thing but did not work. Before making PCB i sent my schematic to Mr. Joel for review.

I am attaching my schematic here please check if something is wrong there that i can not figure out. Waiting your help.

ps: The pcb is small so my usb traces is short and i use usb layout guideline for my design.

Burak SAKACI

Thanks

over 8 years ago

0 Joel Jimenez0 over 8 years ago

TI__Mastermind 18655 points

Hello Burak,

Could you please swap the unit to see if the failure follows the device?

Would it be possible for you to share a protocol analyzer capture when connecting the failing device?

The schematics show multiple 3-pin headers, could you please give details on the current pin position?

Also, please send your pcb layout via email.

Regards

0 burak sakaci over 8 years ago in reply to Joel Jimenez0

Prodigy 25 points

Hi Joel;

-I tried swap. But results is same.

-3 Pin Headers;

Default;

MODE= GND

EXTMEM= 3V3

EEDATA= GND

EECLK= FLOAT

BUSPWR=3V3

But I tried all possible selection for these pins.

- I will send layout your email.

Thanks.

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TUSB2077A: Device Not Recognized / Crystal Not Oscillating