TUSB211: Embedded Host eye diagram

Zach Solheim

Part Number: TUSB211
Other Parts Discussed in Thread: TUSB216I

Directly from our embedded host, we don't pass the signal quality test for HS data. Will this IC be able to correct it, or will we need a completely different solution? We've tested with the TUSB211 eval board and had no luck. Just curious if there isn't a solution with sole signal compensation for this application.

Here is the eye diagram currently:

Please let me know when you get the chance.

Thanks,

Zach

over 2 years ago

0 WIN Maung over 2 years ago

TI__Expert 3655 points

It is just a test issue. I have asked what test fixture are you using and what sequence are you using. the device is not activating during eye test because of sequencing issue.

Please compare CD/ EN_HS pins state when you are testing eye vs normal operation. the pins should be high when the redrive is active.

again it is important that you share the exact steps that you are doing to capture eye in embedded test host. are you following this method? https://www.testusb.com/shop.htm

0 Zach Solheim over 2 years ago in reply to WIN Maung

Prodigy 20 points

Hello,

We follow the sequence stated in SLA5993:

1. Power relay board and set it to the "init" position
2. Connect the "test" port of the relay board to the TUSB21XX's input
3. Connect oscilloscope to relay board
4. Connect head unit/embedded host to the TUSB21XX's output and power it on
5. Toggle RSTN (reset) on TUSB21XX
6. Connect VID/PID test host device to the "init" port of the relay board
7. Set relay board to "test" position

We are using the relay board from Allion pictured here:

Are there any steps in this process that could be improved upon? We are ensuring that we follow the correct sequence. The HS_EN does not go high after relay board gets set to Test. Only the CD stays high. Would this mean no test packets are being sent through vidpid?

Thanks,

Zach

0 WIN Maung over 2 years ago in reply to Zach Solheim

TI__Expert 3655 points

Is HS_EN high after step 6?

0 Zach Solheim over 2 years ago in reply to WIN Maung

Prodigy 20 points

Following the procedure, HS_EN is on after step 5, but as soon as PIDVID is connected, the CD goes high and the HS_EN goes low. If we run the procedure the same way, while leaving the relay board in "test" position the whole time; the green LED comes back on after step 6, but then shuts off again soon after.

Hopefully this helps resolve the issue.

Thanks,

Zach