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Forum: FPGA, VHDL & Verilog text mode vga


von Sizeofrawdata S. (sizeofrawdata)


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Hello, I have a VGA device with which I draw any character from the ROM 
(but only one) on the screen, but I would like to write several 
characters on the screen and for this I need to connect the RAM. But I 
do not know how to connect in the code ...
Please look at my code and say what needs to be fixed / added to it.

von Sizeofrawdata S. (sizeofrawdata)


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file ROM

von FPGA zum Spass (Guest)


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You do not describe what you REALLY want to do.
But in any case:

assign char_addr = 7'h41;//symbol A

This is a fixed assignment -> make is variable, controlled by whatever 
you like.

assign text_bit_on = (pixel_x[10:3] == 1 && pixel_y[10:4] == 4) ? 
font_bit : 1'b0;

This is the position you are drawing.



Why not start with something like this:

char_addr = pixel_x[10:3];
text_bit_on = 1'b0;

It should draw all the chars 0..255 until your x position goes beyond 
screen.

von And in the beginning, ther was the character 'a' (Guest)


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There are at least 2 projects featured on this site with "FPGA displays 
characters on a VGA screen. IT's VHDL and German, but the principle is 
clearly visible:
https://www.mikrocontroller.net/articles/Retrocomputing_auf_FPGA#Textausgabe
https://www.mikrocontroller.net/articles/Durchblicker#Zeichendarstellung

von Sizeofrawdata S. (sizeofrawdata)


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FPGA zum Spass wrote:
> It should draw all the chars 0..255 until your x position goes beyond
> screen.

Thanks for the answer, I want to write a string of characters from the 
wart or keyboard (or when you click on the button), for this you need to 
transfer the characters in RAM and from there draw them on the screen 
(probably) I don’t know how to do this ...

von Sizeofrawdata S. (sizeofrawdata)


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And in the beginning, ther was the character 'a' wrote:
> IT's VHDL

thank you but i don't understand VHDL(

von Sizeofrawdata S. (sizeofrawdata)


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FPGA zum Spass wrote:
> You do not describe what you REALLY want to do.

I want to add 6 buttons (for the character code) and write the word 
“hello” horizontally, how can I do this?
example:
input [6:0]keys
......
assign char_addr = keys;

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