DS90UB926Q-Q1: please help check UB926 eyediagram

sorry, the read marked time should be 110ps, i think.

trise and tfall is measured around 120ps, near uplimit of UB925 spec.

Hi Tao,

What specifically are you looking for?

Are you seeing an issue in the display or a loss of lock?

We recommend using the MAP tool thorough our ALP software to get the best link measurements. This is the user guide on how to use the tool.

Best Regards,

Gil Abarca

Dear Gil,

we received a NG sample from customer, issued white screen. but we cannot reproduce the NG. so we are checking all kinds of timing and circuit for some probille risk.

when we try to check eye diagram we have this problem if it may cause any risk of white screen? for example, DE,HS,VS signal transfer error

BTW, another question, is there a timing from vdd power on to I2C can work? customer inquire this for sw desgin. is it tPLD? and what is tSD.

Dear Gil, below is for f=15 to 45M, how about 85M.

Hi Tao,

I will get back to you by the end of the day 12/14.  

Best Regards,

Gil Abarca

Hi Tao,

What exactly do you mean by "white screen"? Can you provide an image? This would not be caused by any link margin issue which could be observed from the eye diagram.

Regards,

Ben

Dear Gil,

in very low change, the device will show white screen as below when igni on(car device display),  and keep. unplug and plug again Display unit cable, or restart by IGNI off and on can recover to normal display. 

we cannot reproduce the abnormal so this block us. in normal display we cannot find any abnormal timing with DE,HS,VS,RGB,SPI(LCD initial only).

we tried short D+,D-,DE,VS signal but it recover wen short removed. cable is also checked no issue.

what do you suggest.

Hi Tao,

What do you mean by low change? Can a 925 or 926 digital reset recover the video? Does the issue occur with PATGEN?

Best Regards,

Gil Abarca

Dear Gil,

sorry, my fault. that is very low chance. mean we cannot reproduce during about 1 month test. 

reset pin is hardware reset ,no gpio control. 

actually, now our biggest problem is cannnot reproduce it.

Hi Tao,

Did this only happen one time? It would be very difficult for us to help debug this issue if it cannot be replicated.

Regards,

Ben

Dear Ben,

we only reproduced 1 time in the beggining, then never reproduce during 1 month test. so this is really difficult. so we want to check any other probible cause.

could TI give any posiibility suggestions from fpdlink side?

BTW, customer ask the timing from power on to i2c can work, i found below discription in spec.

1.is tSD red marked position?

2.the table is f<45M, how about f=85Mhz?