AM3352: AM3352 USB Eye Diagram Pattern

Daniel Cheng1

Part Number: AM3352

Tool/software:

Hi Expert,

The customer uses AM3352BZCZ80, and the USB interface in the figure below is set to USB Device directly connected to the external connector.

A customer wants to test the eye diagram of a port, but after running the command, they find that the interface cannot receive the USB 2.0 pattern printed by the USB Association command. What firmware settings should be made to test the USB eye diagram?

Thanks

Daniel

10 months ago

0 Stanislav Stilyanov 10 months ago

TI__Mastermind 25080 points

Hi Daniel,

First thing I can see is that USB1_VBUS sense needs to get attached to USB VBUS voltage via resistive divider. This pin senses VBUS voltage presense.

Thanks,

Stan

0 Daniel Cheng1 10 months ago in reply to Stanislav Stilyanov

Mastermind 8195 points

Hi Stan

The tab symbol next to USB_VBUS actually indicates a connection to the USB connector VBUS. USB functionality is present. Currently, I'm using the USB Association's tool, XHSETT version 1.3.6.7, on a PC.

I've given the AM3352 a command, but it's not generating a TestSet pattern to test the USB eye diagram.

Thanks

Daniel

0 Stanislav Stilyanov 10 months ago in reply to Daniel Cheng1

TI__Mastermind 25080 points

Hi Daniel,

Did you try also with this tool :USBHSETT also from usb.org?

Regards,

Stan

0 Luis Parga 9 months ago in reply to Stanislav Stilyanov

TI__Intellectual 1320 points

Hi Daniel,

For device mode, USB_ID pin needs to be left floating. The above schematic capture does not reflect this. Please confirm USB_ID state in your system.

Once this is done and assuming you are using Linux, the 'modprobe g_zero' commands needs to be used. Are you able to see the below after entering this command?

Please advise.

Best regards,

Luis Parga

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AM3352: AM3352 USB Eye Diagram Pattern