DS90UB924-Q1: DS90UB924-Q1 link problems

Hi Dany.

Happy to provide support on this matter. Can you elaborate on your board layout and how you are connecting the 949 EVM to the 924 on your board? What is different between the connection between 949EVM --> 924 EVM and the connection between 949EVM --> 924 on board?

Best,

Nikolas

I'm trying to figure this out, but right now i can't find any important differences between the boards. One of the weird things, is that I can't see a CML OUT on my board, I assume that this would show that serdes is alive somehow. This feature is working on the EVM board perfectly. 

Just an update, I see a received signal on CMLOUTP/N, but can't get a lock. Looks like noise problem? 

Hi Dany,

Nico will get back to you by tomorrow.

Hi Danny,

Thank you for this update - is the received signal you are seeing on the CMLOUTP/N with your 924 EVM different than the received signal on your 924 board?

In any case, let's first work to establish stable lock between the 949 EVM and your 924 board. Do you have local USB access on your 924 board? If so, we have a MAP tool available on 92x and 94x deserializer profiles in Analog LaunchPAD (ALP) under the "Margin Analysis" tab.

You may refer to this user's guide for evaluating the results of the Link from the DES: FPD-Link Margin Analysis Program (MAP) user's guide.

Best,

Nikolas

Hi 

I used this application; I interfaced with the deserializer on my board using Ardvark. The program is not very stable for Aardvark, but I managed to use it. I get all cells in the graph red. In the EVM, using the same cable almost all cells are green. 

But it's very peculiar behavior, I use a 2m cable so signal is quite "strong". The supply voltage on the EVM is coming from the linear regulators, in my board from the switching regulator, but I don't think that supply voltage ripple is so big, will measure.

The circuit looks very similar to the EVM. I will keep testing.

Hi Danny,

Okay, thank you for the update. Let me know when you have results.

Regards,

Nikolas

Hi Nikolas

I don't know what to test next... I can't get lock on my board and margin analysis returns all reds, like there is no physical connection to the cable. Have you encountered anything like this?

I don't know what kind of diagnostics I can use on the chip.

The I2C working good but that's it.

Regards

Dany

Hi Danny,

Thank you for the update. Just to confirm - you mean the polarity of the incoming HSYNC/VSYNC signals, correct?

In any case, please feel free to let me know if you have any other questions.

Best,

Nikolas

Hi

I mean high speed serdes inputs Rin+, Rin-

Hi Dany,

Thanks for reaching out to us. Do you still need help? Are you able to get the video with your board? When you mentioned that you connected UB949 to your board, are you saying the same device UB924?

Let me know if you need help. Please attach your schematic if you can.

Aaron