DS90UB926Q-Q1: Blue screen

Hi Peter,

Are you using color bars? Furthermore, please update us with the results of the 926 pattern. It will help with narrowing down where the issue is. 

Thanks,

Esther

Hi Esther,

Their display module is DLP module which cannot tolerate large PCLK mismatch.

926 pattern could only output 33.3MHz PCLK and DLP needs 31.5MHz, so DLP output nothing when in 926 pattern mode.

Could you ask your colleagues which has experience on FPD-link pairing DLP system?

Regards,

Peter

Hi Peter,

I have several questions:

1) Which type of RGB format are you using?

2) Can you provide a picture of a "blue" display? 

There are several options that you can try:

1) Use an external oscillator on Pin 5 of the 926 rated at 31.5 MHz and try 926 PATGEN with internal timings/external clock. 

2) Swap out the display with one that can accept the 33.3 MHz PCLK and try 926 PATGEN again. 

3) Run the 949 PATGEN with a different display with no other changes. 

Let us know the results of any of these options.

Thanks,

Esther

Hi Esther,

Esther Chang said:

1) Which type of RGB format are you using?

RGB888.

Esther Chang said:

2) Can you provide a picture of a "blue" display? 

I will upload a video later.

Esther Chang said:

1) Use an external oscillator on Pin 5 of the 926 rated at 31.5 MHz and try 926 PATGEN with internal timings/external clock. 

This is not possible because they did not reserve oscillator on their board.

Esther Chang said:

2) Swap out the display with one that can accept the 33.3 MHz PCLK and try 926 PATGEN again. 

Customer also said it is not possible because their board is specialized made for DLP module. 

Esther Chang said:

3) Run the 949 PATGEN with a different display with no other changes. 

Not possible, the same reason as 2).

We are trying to output a red/green pattern and capture the signal on blue lane. What should the blue signal lane(pin19, B0) be when 926 outputs a red/green pattern?

Regards,

Peter

Hi Esther,

Please check the video below.

Regards,

Peter

Hi Peter,

Esther Chang said:

Are you using color bars?

Can you please try using color bars for 949 PATGEN and send a video of the result? It will give us a better idea on the behavior we're seeing, as opposed to using a solid color pattern.

BR,

Esther

Hi Esther,

Please check their display.

They can see abnormal blue lines in the display.

Regards,

Peter

Hi Peter,

Thank you for the pictures. To help narrow down the cause of this distortion, what PCLK are you using when you do 949 PATGEN? It could be an issue with the PCLK tolerance of the DLP display, similar to the 926 case. 

BR,

Esther