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Altera_Forum
Honored Contributor I
882 Views

NEEK Cyc.III - TPG to Touch LCD flackert - bitte um Hilfe

Hallo zusammen, 

 

ich arbeite mit dem Nios II Embedded Evaluation Kit in der CycloneIII Edition mit terasiC Erweiterungsboard. Als Arbeitsprojekt habe ich aus dem NIOS_Evaluation_Kit_v8.0 das Example video verwendet. 

 

Aus dem video Example habe ich erstmal fast alles rausgeworfen. Mein Ziel ist es einen Test Pattern Generator mit dem Touch LCD zu verbinden. Das habe ich dann auch direkt probiert, mit DataFormat Adpater und Timing Adapter dazwischen bekomme ich auch eine Ausgabe. 

 

Ich verstehe nur nicht, warum mein Bild stark flackert. Kann mir jemand weiterhelfen? Muss ich bei dem NEEK Board zwingend über den DDR Memory arbeiten und die ganze Video Pipeline implementieren? 

 

Das SOPC-Design habe ich als Bild angehängt. 

 

Danke vorab!
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7 Replies
Altera_Forum
Honored Contributor I
121 Views

Forgot to add some english text. I am working on a Nios II Embedded Evaluation Kit CycloneIII Edition with terasiC Expansionboard. 

 

From the NIOS_Evaluation_Kit_v8.0 video example I have tried to build a very small test Pattern Generator to Touch LCD example. So iI have got some output an the LCD, but it is flickering very much. 

 

Why doesn't it work to connect the TPG directly to the LCD? Have I got to implement the hole video pipeline and feed the LCD from DDR memory everytime? 

 

I have attached my small SOPC design to the first thread. 

 

Thanks for your help.
Altera_Forum
Honored Contributor I
121 Views

Thanks to all readers of this thread. It is solved. If you have got the same problem, you might want to look into the attached code here: http://www.alteraforum.com/forum/showthread.php?t=6118 

 

Yours, Peter.
Altera_Forum
Honored Contributor I
121 Views

Hey Peet, 

 

I must say I have exactly the same problem as you have, I'm trying to image a test pattern on the LCD of the NEEK LCD (cyclone III edition) but it flickers and the colors are poor. 

I experimented a lot with the PLL settings, because it looks like some clocking problem to me: 

  1. -slower clock values: richer colors and slower flicker 

  2. -faster clock values: poor colors and fast flicker (so the flicker always remains)
 

In the second post you put a link to the VGA example, but I wasn't able to open it in the SOPC builder (the .sof file worked perfectly on the VGA port) so I couldn't look at the pipeline you created. 

 

Would you mind to give me some help, I'v been strugling with this problem for a few days now... My complete project is in the attchment if you want to have a closer look at some newbies mess :p  

 

Thanks for your time, 

Best regards 

 

Hans
Altera_Forum
Honored Contributor I
121 Views

Hello, 

 

I guess the problem here is not a clock issue.  

If you use the logic analyzer you will see, that after a correctly displayed image there is some not desired data on the data bus. This data is interpreted as black by the video sync generator, resulting in a black video frame(s?). Imo the reason is, that the avalon video streaming protocol is package based and the video sync generator does not filter the packages out of the data stream correctly. (i guess sync generator is not package based). 

 

Use the clocked video output IP instead. Another advantage of that IP is, that you dont need the adapters. 

 

regards 

 

Andreas 

 

PS: Don´t shoot me if I am wrong, I am also a beginner. ;)
Altera_Forum
Honored Contributor I
121 Views

Hey Andreas, 

 

It is as you said, the video clocked output of the VIP suite works just fine. Untill now I was using the material from the Picture viewer as a guide to create my own system. 

 

So if I get this right, I can use the SGDMA-scatter module (like used in the picture viewer example) in combination with the video sync generator. 

But if I want to use the alpha blender, test pattern generator,... (VIP elements) I need to use the video clocked output and perhaps the frame reader instead of the SGDMA-scatterer? 

 

In a short way, there are two options a guess: 

 

-VIP SOPC elements only combined with VIP elements (in this case I can use the test pattern generator, alpha blender, videoclocked output,... all the VIP blocks). 

-The video sync generator combined with the SGDMA-scatterer (based on the standard Avalon ST-packaged based interface) system without any further options. 

 

This really makes sense when it comes down to the package-transmission you mentioned... 

 

You've been a great help! 

Thanks again, 

 

Best  

 

Hans
Altera_Forum
Honored Contributor I
121 Views

Nice explanation, Thanks!

Altera_Forum
Honored Contributor I
121 Views

 

--- Quote Start ---  

 

So if I get this right, I can use the SGDMA-scatter module (like used in the picture viewer example) in combination with the video sync generator. 

But if I want to use the alpha blender, test pattern generator,... (VIP elements) I need to use the video clocked output and perhaps the frame reader instead of the SGDMA-scatterer? 

 

--- Quote End ---  

 

That´s how I think it is. The cores from the VIP Suite use the "Avalon-ST Video protocol", therefore streams following other protocols have to be properly converted, e.g. by the use of the Frame Reader instead of the SGDMA.
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