VGA Question


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not sure but take a look at the source code

vga_r <= vga_ram_data(7 downto 5);

vga_g <= vga_ram_data(4 downto 2);

vga_b <= vga_ram_data(1 downto 0);

Maybe the Logicstart was tailored for the VGA driver.

BTW the Arcade Megawing has 12b colours (4 resitors for each colour)

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You are probably right...

iirc, most of the original arcade boards used 15Khz/60Hz...

from the manual :

Supported Display Resolution

•Computer formats

Resolution @ Refresh rate


640 x 480 @ 60Hz

800 x 600 @ 60Hz

1024 x 768 @ 60Hz

1280 x 1024 @ 60Hz

1360 x 768 @ 60Hz

1600 x 1200 @ 60Hz

1920 x 1080 @ 60Hz

I wonder if this is something that can be adjusted in the vhdl ?scan doubler? file

sadly, @ work atm so can't even peek there. of course, who knows what else that would break.

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As to why 2 bits for blue, but 3 for green and red... The eyes are more sensitive to red and green than blue, so an doubling the number of red and green levels vs blue gives best results.

I've had Pacman running on a older 40" Sony V series, So it can't be that far off... Maybe run iSim and check the hSync frequency.

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that makes total sense.

i decided that i am not going to worry bout running the arcade stuff on the big tv since its all sideways anyways, and the wife would kill me if i turned the flatscreen on its side :)

i will try with the A2601 stuff see if that shows up tho.

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