DS90UB941AS-Q1: panel jitter

Hi, Sir,

This is panel info:
uVisWidth = '1920'
uHsyncFrontPorch = '100'
uHsyncWidth = '12'
uHsyncBackPorch = '20'
uVisHeight = '532'
uVsyncFrontPorch = '8'
uVsyncWidth = '2'
uVsyncBackPorch = '6'
uPixelFreqInHz = '67469760'
bDEPolarity = '0'

Hi,

How was this issue isolated to a jitter issue on the 941? 
How many failures do you have and what is the fall-out rate?
Have you tried ABA swap? Putting the suspect IC on a known good system and visa versa, does issue go away?

user6526159 said:

it is hard to measure the signal with an oscilloscope。

What signal are you trying to capture? Please provide block diagram of your system.

Regards,
Fadi A.

Hi, Sir,

1)

First When panel jitter, the lock pin of 948 is low. however the mipi clk form SOC looks ok. please refer the picture.

Except the mipi clk jitter, what other reasons may 941 lock loss?

2)

First, we have made some improvements from the host side. Now we hope to get some help from Ti.

The failure rate is very high. Some machines do not reappear all the time, and some machines reappear all the time, such as video. 

3) ABA Swap? we can try it.

4) The block diagram 

Thanks!

Hi,

For the DS90UB941AS-Q1 or DS90UH941AS-Q1 serializer devices, the measurement methodology for DSI or REFCLK input jitter are provided in the link below:

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1050269/faq-ds90ub941as-q1-dsi-or-refclk-jitter-measurement?tisearch=e2e-sitesearch&keymatch=ds90u%2A

Please take a look and make sure to follow the steps provided in this link.

Regards,
Fadi A.

Hi ,Sir,

I know that clock jitter is one of the reasons for losing locks. we had improved the quality of mipi signal. but sometime panel still jitter.

And I want to know whether there are other reasons for losing locks.