15hz CRT support through CGA/EGA card simulation?

Matsu
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Re: 15hz CRT support through CGA/EGA card simulation?

Unread post by Matsu »

I found these settings on a reddit post from a month ago, it works almost perfect on my PVM monitors. Though you have to enable underscan to display the whole picture.

1ejZkwH.jpeg
1ejZkwH.jpeg (408.56 KiB) Viewed 84 times

Add the following lines to the end of your MiSTer.ini

[ao486]
video_mode=640,6,56,66,224,14,8,18,12000
vga_scaler=1

Update: It's actually better to use vscale_mode=1

[ao486]
video_mode=640,6,56,66,224,14,8,18,12000
vscale_mode=1
akeley
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Re: 15hz CRT support through CGA/EGA card simulation?

Unread post by akeley »

Matsu wrote: Wed Apr 07, 2021 1:11 pm [ao486]
video_mode=640,6,56,66,224,14,8,18,12000
vga_scaler=1
I tried this on my 15khz Trinitron via Direct Video, but there was no change from my usual vertically-squished display.

Are there perhaps any other settings I should try changing? (I only have composite sync & direct video set to 1 in the ini, rest is default)
FoxbatStargazer
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Re: 15hz CRT support through CGA/EGA card simulation?

Unread post by FoxbatStargazer »

Direct video ignores video modes and uses its own default. You should set it to 0 when trying to output your own video mode.
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darksakul
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Re: 15hz CRT support through CGA/EGA card simulation?

Unread post by darksakul »

I prefer HDMI out, there are less guess work for me.
Especially there so many different games with different output standards
It is my great regret that we live in an age that is proud of machines that think and suspicious of people who try to.
akeley
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Re: 15hz CRT support through CGA/EGA card simulation?

Unread post by akeley »

FoxbatStargazer wrote: Fri Apr 09, 2021 6:36 pm Direct video ignores video modes and uses its own default. You should set it to 0 when trying to output your own video mode.
I added "direct video=0" to Matsu's setting but the image started rolling heavily.
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Re: 15hz CRT support through CGA/EGA card simulation?

Unread post by FoxbatStargazer »

That means the video mode isn't tuned for your display. I don't know what is wrong, but I do know that direct video off is the only possible way you can even use a video mode line in the ini. With direct video on you just have to live with whatever resolution the core gives you.

It sounds like you have a consumer grade TV (if a decent one) so it might be more restrictive about what it can handle than a PVM. 224 tall/60hz is a bit short for example, you might need 240 or 244 for something stable (but then you are back to squished picture...)
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Re: 15hz CRT support through CGA/EGA card simulation?

Unread post by akeley »

Ok, thanks, I just tried it on the off-hand chance it might work, but didn't hope for much. Perhaps it has something to do with Direct Video itself.
I was surprised to see this core actually displays something at all on my TV, before it was strictly 31Khz. So, maybe one day...

For now I'm super happy that the VGA output has improved substantially anyway.
Matsu
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Re: 15hz CRT support through CGA/EGA card simulation?

Unread post by Matsu »

Instead of vga_scaler=1, you can also try vscale_mode=1

vga_scaler=1 gave me big black lines on most resolutions.
with vscale_mode=1 all resolutions seem fine.
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