Macro

Video inversion for Invaders

6 posts in this topic

I was hoping to clean this up a bit, but not had a chance yet, so here in case anyone wants to play ...

you need to lose dblscan.vhd from the project (the original scan doubler) and add the following source, VGA_Invert.vhd - this uses the same interface (was one of the limitations I set myself), but you will also need to generate a memory core to go with it - this needs to be called u_invert and have the following characteristics

simple dual port ram

write width 2

write depth 65536

ram A

write first

use ENA pin

ram B

write first

always enabled

with that added, then it should synthesise OK and work for you.

there are 2 'magic numbers' in the source that I used to centre the screen on my monitor - the original doubler has the picture way off to the left - your monitor may be different and need these changing.

  --

  -- Output Screen Positioning

  --

  constant Horizontal : natural := 140;

  constant Vertical : natural := 268;

the vertical one counts backwards, so needs to be > 244 (the number of vertical pixels)

VGA_Invert.zip

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This is great, how hard would it be to modify this to rotate the video 90 degrees so the monitor doesn't have to be turned sideways?

Jack.

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ok, quick alteration to swop X/Y over and invaders the 'normal' way up to save you tilting the screen.

VGA_Invert.zip

Edited by Jack Gassett
Fixed bad attachment

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Thank for than change. I was looking for something like that. But i see that the first zip is corrupt. Can you repost it wiith the memory core for a standard xlinx? Im new in this of fpga...

Thanx in advance. 

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