Converting RGB to VGA using FPGA

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Enlighted (6033)

NYYRIKKI's picture

26-10-2014, 12:19

Ok, it seems that you have now implemented the adapter pretty much same way as I've used to see it implemented on modern TV's. -> Either there is huge cutting problem or then the scaling causes this kind of bad looking characters on screen. What I like in your design is that you can actually select the behavior with DIP-switches!

Thank you for all this explanation. I have learned a lot about the nature of the problem. Before I thought that the problem was digitizing the picture with correct resolution, but now I see that the actual problem is how to output the digitized buffer to screen.

Because output of MSX screen without scaling would require resolution more close to 680px instead of 640px there is always scaling needed even if higher resolution is used. In theory we would need to go up to 1368x768 to get rid of the problem completely. (Did I get it right?)


Enlighted (6933)

ARTRAG's picture

26-10-2014, 14:11

Just a silly idea: how would the picture look like resorting to some sort of time interpolation?
Could you arrange to drop or not a couple of pixels on time basis?
On odd frames you drop a given couple of pixels, on odd frames you do not drop it.
In this way you could blur the edges of the missing columns using time interpolation.

By retrocanada76

Hero (542)

retrocanada76's picture

26-10-2014, 16:14

SymbOS doesn't work on me. When I click on an icon is says it could not find the drive. And my IDE was supposed to be sunrise compatible but it turns out it might have compatibility issues.

Regarding the video I'm having trouble doing more stuff. Things just stop working or have a bad oscillation due to the timing issues. I had to experiment several places where to add the shrinking algorithm that would not cause problem.

Last time i tried ouputting 800x600 I wasn't able to do it. Seems the throughput is already on the limit. Increasing the resolution puts higher pressure on the buffer.

By edoz

Prophet (2478)

edoz's picture

26-10-2014, 16:36

To bad that symbos didn't work I was eager to see it with your display adapter.. however maybe your working path is not correctly set ? After booting SymbOS could you go to START -> RUN -> BROWSE ? (And see the disk ?) If so than your IDE works correctly! start appcp.exe to set the correct system path. >>Sytem icon and then General TAB.. Set the system path where all the EXE files are!
For example (C:\APPS\ or C:\SYMBOS\) If you cannot browse your drive which partition did you choose during ? And was the IDE automatically detected ?

See also : Link

By retrocanada76

Hero (542)

retrocanada76's picture

04-11-2014, 18:47

I finished the desing of the board:

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