DLP4500: Cannot continuously display 2 pattern sequence patterns in single 24bit video stream data in the pattern sequence mode

Pang,

It sounds like you are saying you have every other frame of your video feed shows empty data, is that correct? Are you using a constant video stream, or are you starting and stopping the data? Are you sending VSYNCs with no data attached?

Regards,

Philippe Dollo

Dear Philippe Dollo,

I am using constant video streaming so the video data is not empty. Besides, the video data is always send together with the VSYNC.

Previously I am using the 7bit for the pattern sequence settings. Now I tried to set the pattern settings to 4bit shown below. The projection signal looks ok.

Blue signal is VSYNC and pink signal is TRIG_OUT_1 from DLP4500EVM. I am using same streaming program do to the test.

Best regrads,

Pang

But I need to use 7bit pattern sequence settings. What cause the 7bit pattern sequence settings cannot work as 4bit pattern sequence settings?

Weng Yeon Pang, 

I am not sure if you have already tried the following check - please use the validate sequence feature of the GUI to re-check that the sequence you want to want to display is supported by the system or not.

Let us know your findings. 

Regards,

Mayank 

Dear Mayank,

Thanks for your reply.

Everytime I change the pattern sequence settings, I will use the validate sequence button of the GUI to validate the sequence settings and the results are passed.

I have try the below video data settings but the behavior still the same. Delay of 1 frame everytime then only the EVM starts the pattern sequence.

Pixel Clock = 146 MHz

Horizontal:

Resolution = 912

Front Porch = 56

Sync Pulse = 64

Back Porch = 10

Vertical:

Resolution = 1140

Front Porch = 17

Sync Pulse = 10

Back porch = 3

Horizonal Sync Frequency = 140.12 kHz

Vertical Sync Frequency = 119.76 Hz

Horizontal Period = 1042 Pixels

Vertical Period = 1170 Lines

Can you share the settings or setup that you able to function the EVM to display two 7bit pattern sequences continuously in pattern sequence mode with parallel RGB interface as pattern source?

Thank you.

Best regrads,

Weng Yeong

Weng Yeong,

Thanks for the feedback. The team needs some time before getting a response back to you. Expect something within the next week.

Best Regards,

Philippe

Dear Philippe,

Looking forward to your feedback. Thanks a lot.

Best regards,

Weng Yeong

Weng Yeong,

No problem. Thanks ahead for your patience. Will keep you posted.

Regards,

Philippe

Dear Philippe,

Any findings from your team? Thank you.

Best regards,

Weng Yeong

Weng Yeong,

Unfortunately, we were not able to look into this query till now. We will try to look into it and update you with our findings in a couple of days. Kindly expect an update by 4/15/21. 

Regards,

Mayank

Dear Mayank,

Any findings at your side? Thank you.

Best regards,

Weng Yeong

Hello Weng, 

The team is still working on this, we will get back to you soon.

Regards,

Mayank

Dear Mayank,

Looking forward to your team reply soon. Thank you.

Best regards,

Weng Yeong

Weng Yeong,

Thanks for your patience. 

Regards,

Philippe

Dear Philippe & Mayank,

Got any any finding on this issue? Thank you.

Best regards,

Weng Yeong

Weng Yeong,

There may be a problem with your 120Hz timings. Did you compare your timings to those in the DLPC350 datasheet? They need to match exactly for 120Hz mode to work.

https://www.ti.com/lit/ds/symlink/dlpc350.pdf

Best Regards,

Philippe

Dear Philippe,

I have followed the input blanking timing that stated in the datasheet. 

Besides, I want the DMD to project two 7bit pattern sequence in one frame transfer which showed in the diagram below. So i am not using 120Hz for the Vsync frame rate.

In my test, I am using 59.81Hz for Vsync frame rate. Clock frequency (P1A_CLK) is around 73Mhz. So from the results, you can see that there is alaways a delay one frame when project two 7bit pattern sequence in one frame. But when project two 4bit pattern sequence in one frame, it does not have this issue. 

Results in two 7bit pattern sequence in one frame:

Results in two 4bit pattern sequence in one frame:

I am using the same settings and setup to run the test. I just changing the pattern sequence settings in DLP4500GUI from two 7bit pattern in one frame to two 4bit pattern in one frame. I want to project two 7bit pattern in one frame continuously. What settings I need to use?

Thank you.

Best regards,

Weng Yeong

Weng Yeong,

The timings you showed in the first screenshot are actually for 120Hz. If you are configuring the system for 60Hz, then there may be a problem with your setup.

Can you explain what you mean by the above in a bit more detail?

- Philippe

Dear Philippe,

Ok. I will check my source input blanking timing for low frequency. Thank you.

Best regards,

Weng Yeong

Hello Weng Yeong,

You are welcome to the support. Please let us know what you find for the source blanking timing at lower frequencies when convenient.

Regards,

Austin

Dear Philippe,

I am using the same source blanking timing as the 120Hz, but I reduce the pixel clock frequency (P1A_CLK) to achieve 60Hz. Is this the correct way to do it?

Thank you.

Best regards,

Weng Yeong

Dear Mayank,

At the video signal information in the Light crafter GUI, the start position for the first active pixel and first active line is start with 0 or 1?

For example, the sync pulse is 10 and back porch is 10, the active position is 19 or 20?

Thank you.

Best regards,

Weng Yeong

Dear Philippe,

Thanks for your reply.

With the 120Hz blanking timing showed in the diagram below.

The position of the first active pixel would be at 73 (HSYNC high + HBP) ?

The position of the first active line would be at 12 (VSYNC high + VBP) ? 

Best regards,

Weng Yeong