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Altera_Forum's avatar
Altera_Forum
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17 years ago

DE2 board VGA Dispaly

Hello All,

I am trying to use the board's SRAM to store an image and dispaly it on the screen.

I designed a project using QuartusII and was able to manage the

VGA dispaly timing. I used a reference design from John Loomis Webpage.

http://www.johnloomis.org/digitallab/vgalab/vgalab3/vgalab3.html which

is very helpful and nice. However, I am having a problem in dowloading the

raw image file to the SRAM. My question is:

How can I get a typical 640 X 480 bitmap image to be stored in the SRAM?

I tried to use Terasic ImgConv, but it doesn't work :(

I appricate your help.

Thanks

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  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    Im sorry, im a total beginner and using the DE2-70 board trying to simply get a camera input to the board where it processes RAW to RGB and output to a LCD screen. can you post a video on youtube on how to do what you are saying? that would clear things up so much and im sure other ppl would love it as well! thanks! :D

  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    I wasn't able to run it, as my VGA port would only ouput seven colours.

    And yeah, the video would be great!:D
  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    Oh sorry´.

    That code was made for DE2 board it has VGA DAC chip with 9 bits inputs for RGB each.

    What can I show in the video ?? I post the code :confused:

    Regards.

    Alberto.
  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    maybe just the procedure on how to compile it in quartus? also im sorry i dont speak spanish. i dont really understand the comments in your code :(

  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    Hi.

    Nothing special to compile it in Quartus, just Menu - Processing - Start Compilation. and no special preferences in Quartus selected, just by default values.

    Regarding the comments in Spanish, I will upload a translate table with the meaning of each comment...sorry, I forget about that comments.

    I've not too much time free now for realize a video, but I will, when I'll get some time free.

    Regards.

    Alberto.
  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    that would be great :). i was just wondering if you wrote the entire code yourself? or did you use the sopc builder or nios? or altera monitor program? thanks :)

  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    Hi.

    What are you talking about ayhoung ??

    Did you download my code from the# 6 post of this thread ?

    I didn't use NIOS II for this, & Altera monitor program is usefull to check some NIOS II coding.... seems to be that you're misunderstanding what I did.

    Mi final target was to get 640 x 480 24 bit RGB picture on the VGA out, maybe I continue with this some day, if I'll have some free time.
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Hello everyone,

    Can anyone explain to me how to generate the R, G, B signals (used in DE2 board) from a gray image?

    let me explain. I have an array of pixels (representing a gray image) stored in the DE2 SRAM. How do I generate the 10-bit VGA_R,VGA_G, VGA_B needed from each pixel? How do I generate VGA_R, VGA_G, and VGA_B from a gray pixel that ranges from 0- 255?

    Please help
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Sorry Monish If I understood correct your question, you have a gray scale image in the SRAM.

    So, you couldn't generate a color image, but, you can get each pixel of the SRAM and then, assign VGA_R = image_pixel, assign VGA_G = image_pixel, assign VGA_B = image_pixel.

    You'll have only eight bits, but if first you shift the data two times left, you'll have a variable of 10 bits to assign to the VGA R,G,B wires.

    Your data will look like this: 10'b 1111111100 for a maximun pixel bright, so 256 differents levels, for this 10 bit D/A DE2 vga chip.
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    I tried it and the image appeared dark (not bright).

    But please explain to me why shifting by 2?!!!

    Shifting by 2 is equivalent to multiplying by 4 which makes the range now from 0 --> 1023 (10 bits for VGA_R, VGA_G, VGA_B). Would the image still look the same after the shift?

    Many Thanks