Comments for John Roach

Comment on How to add images to DataGridView cell using C# and Windows Forms by Sneha

Sneha — Wed, 16 May 2012 13:38:49 +0000

Thank You So much

Comment on Getting VGA output using VHDL and a Spartan-3AN board by John Roach

John Roach — Wed, 09 May 2012 10:18:18 +0000

Sure thing just simply change the values for
red_out : out std_logic;
green_out : out std_logic;
blue_out : out std_logic;

Since all colors consist of red, green and blue you will be able to create couple of colors. However if you wish to create even more colors you will need to connect all connections of the VGA to your FPGA using the UCF file. Also you will need to re-type the red_out, green_out and blue_out to std_vector’s simply because now red_out will have not only the possible values of “0″ and “1″ but also “0010″ which is another shade of red. You can play around with the colors to find the exact color you wish.

Comment on Getting VGA output using VHDL and a Spartan-3AN board by Laro

Laro — Tue, 08 May 2012 18:05:44 +0000

Hi! I have a question if I succeedeed to draw those squares(from Simon says game) and if want to change the colors of the squares how would I do that? Can you give me the idea to do that?

Comment on Projects by John Roach

John Roach — Mon, 07 May 2012 07:02:46 +0000

That is actually the screen sizes. Check the screen size related graph at http://johnroach.info/2011/01/15/getting-vga-output-using-vga-and-a-spartan-3an-board/ There you will see that one vertical scan is actually in the size of 525 however I wanted a black border hence 519. And I wanted to scan the are horizontally from 39 to 144. As I said please check out the CRT screen scan graph. You will understand than…

Comment on Projects by Laro

Laro — Sun, 06 May 2012 14:21:57 +0000

I tried to understand your code, but why did you set the value for the horizontal counter to be >=144…and the same question for the vertical one?

37: if clk25′event and clk25 = ’1′ then

38: if (horizontal_counter >= “0010010000″ ) — 144

39: and (horizontal_counter = “0000100111″ ) — 39

41: and (vertical_counter < "1000000111" ) — 519

Comment on Projects by John Roach

John Roach — Sun, 06 May 2012 06:59:59 +0000

Unless you are using intense graphics you have no need of ram. You can simply use a switching mechanism. RAM is good when you have multiple dynamic data to be viewed. For example a snake game where the snake collects points and the length of the snake increases with each point.

Comment on Projects by Laro

Laro — Sat, 05 May 2012 20:48:05 +0000

Hi John! Me again:)). I have a question for you , if you can help me. As I told you, I have to display 4 images and the selections will be read from the board’s buttons. Should I use a RAM memory for the implementation, or I don’t need it? Are the 2 counters enough?

Comment on Projects by Laro

Laro — Thu, 03 May 2012 14:07:01 +0000

Thank you! I will try to. Have a nice day!:)

Comment on Projects by John Roach

John Roach — Thu, 03 May 2012 13:58:32 +0000

Well the thing is that you first must learn how to program in VHDL.
Please check
http://www.seas.upenn.edu/~ese171/vhdl/vhdl_primer.html

And the sample code for a snake :
https://github.com/freaktm/VHDL-Snake-Game/tree/master/vhdl

And also check out my code in the previous link… And try to understand it… Because the code in that posts simply colors the screen red…
Which will be a great “Hello World!” program for you. Also if you have any questions on my code please do ask!

**** PS : Remember to connect the FPGA to your Video! Basically you need to edit your UCF file.

Comment on Projects by Laro

Laro — Thu, 03 May 2012 12:50:57 +0000

Well, as I said in the first comment I’m new on VHDL. I’m trying to understand as much as I can, but I’m a little confused:). I read your post relating VGA and I’ll try to understand the code. But now I’m wondering what I should write in order to display only a dot on the screen. I think this is the easiest thing to do…but I wasn’t able to do it:-S