MiSTer with I/O Board VGA Output

Nickola
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MiSTer with I/O Board VGA Output

Unread post by Nickola »

Hello,

I have this setup :

- DE10-Nano
- 128Mb SDRam Module
- I/O Board v6.1

I've put a 128GB Samsung SD Card set up as detailed in the tutorial, connected to my TV through HDMI.
I proceeded with Downloader / Updater scripts.
I've not yet put games.

So far, the mister is running well. I tried the "input test" with no issue.

Now, from the beginning I intended to use an old VGA 19" TFT screen that displays in 1280x1024@60Hz
To do so I'd like to use the IO Board's VGA Output.

I've set the options in Mister.ini to display the right resolution, but when hooking it to the screen, it immediately displays a warning message stating

Code: Select all

cannot display this video mode, change computer (:)) display input to 1280x1024@60hz
Can you please help ?

Have I missed something ? (more than likely)

Thank you

Nickola
Nickola
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Re: MiSTer with I/O Board VGA Output

Unread post by Nickola »

Hello again,

After some more reading, and further investigating, I had not activated the "Forced_ScanDoubler=1", so I now have a correct display on my VGA LCD Screen.

What's now keeping me from being completely happy with my setup is the actual resolution displayed...
FoxbatStargazer
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Re: MiSTer with I/O Board VGA Output

Unread post by FoxbatStargazer »

set forced_scandoubler=0 and vga_scaler=1. By default Mister is going to output the system's original resolution over the VGA port, you need vga_scaler to instead use the same resolution as HDMI.

Although if possible, usually you get better results with DVI into old flat panels, as the signal stays digital the whole way through. HDMI->DVI adapters are common, and just set dvi_mode=1 in mister.ini.
Nickola
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Re: MiSTer with I/O Board VGA Output

Unread post by Nickola »

Thanks , I'll try this.
By the way, this Flatscreen is that old that it does not have a DVI.

[Edit]
@FoxbatStargazer : It's definitely better with the options you stated.
[/Edit]
Nickola
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Re: MiSTer with I/O Board VGA Output

Unread post by Nickola »

Hi,
Now that the MiSTer is able to display a proper résolution on the VGA Screen, I have a new question :
Is there a way to prevent the use of multiple "video profiles" between the Cores ?

I mean (maybe I'm not using the right words) :
- If I start the Genesis Core, with an US/JP Game, the output will be in "NTSC" 60Hz, and displayed properly on my screen (centered, almost all display surface covered)
- If I now switch to an Euro Game (PAL) on the same Core, the image will go all over the place, not centered, not even fully displayed (once I hit the Auto config on the screen to have it autocalibrate the display timings etc)
- It seems clear the switch between NTSC and PAL is the issue as there's a difference in frame rate 60Hz vs 50Hz.

So, is PAL 60hz available ? Is there something to do in order to have the display profile consistent throughout Cores ?

Thanks
FoxbatStargazer
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Re: MiSTer with I/O Board VGA Output

Unread post by FoxbatStargazer »

Now that we are using the scaler, you can force refresh rates, yes. Use the refresh_min variable in Mister.ini. If the core tries to output something below the refresh, it will instead use your video_mode timings as if it was vsync_adjust=0, which is probably 60 hz. Note this means that 50 hz content will have to be interpolated to 60 hz before it is output. This means smooth scrolling on Amiga or C64 will become jerky.

Another approach is to use the video_mode_ntsc and video_mode_pal lines. That lets you create a separate set of timings that might get 50hz content to display properly. You will have to come up with timings for a custom video mode though for 1280x1024 @ 50hz.
Nickola
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Re: MiSTer with I/O Board VGA Output

Unread post by Nickola »

FoxbatStargazer wrote:[...]Use the refresh_min variable in Mister.ini. If the core tries to output something below the refresh, it will instead use your video_mode timings as if it was vsync_adjust=0, which is probably 60 hz. Note this means that 50 hz content will have to be interpolated to 60 hz before it is output. This means smooth scrolling on Amiga or C64 will become jerky.
I understand the mechanism, but would it be possible for the core to execute @60Hz (and so no interpolation) whatever the region. Being mostly interested in Consoles (and Arcades), it would be more beneficial. As old consoles usually ran 20% slower to accommodate to 50Hz output.

I'll have a go with the options to see If I can get to something ^^
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Re: MiSTer with I/O Board VGA Output

Unread post by Nickola »

@FoxbatStargazer : it worked. I stated the option for refresh_min/max to 60Hz ... Et Voilà ... ;)
Display is always set up to 60Hz whatever the Console/Rom region I start.
And I've not noticed any strange display behaviour.

I think this topic has come to its end regarding the original subject.
Thanks a lot for your help.

Nickola
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Re: MiSTer with I/O Board VGA Output

Unread post by FoxbatStargazer »

Again I should note the scaler is interpolating up to 60 frames, the underlying game still runs at whatever speed the Mister is told to. So PAL stuff probably still runs at 50 underneath, even though your display is receiving 60.

For example in the MegaAGS compilation for Amiga, in the options there is a "force 60hz" which will make 50hz games run at a real 60hz. Some work mostly fine with maybe an oddity here and there, others crash completely.

For the Atari ST, you can choose a US or UK (EU?) bios to control the default refresh rate. Many apps will respect that, working well enough in either mode. Others will break, still others will override the default and insist on 50/60hz themselves. There's also programs to run in TOS that can flip between 50 and 60 but again, that relies on whatever executable you run next to respect the current mode and not override it.

Don't have any experience with C64 but there is probably some mechanism to force games to run at 60hz, with similar caveats about results.
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Re: MiSTer with I/O Board VGA Output

Unread post by Nickola »

One last question...

Can i specify one resolution for HDMI, and another for I/O Board's VGA output ?
Like 1920x1080 for HDMI, and 1280x1024 for the TFT I have on the VGA Port ?

Thanks
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Re: MiSTer with I/O Board VGA Output

Unread post by FoxbatStargazer »

You cannot, there's only one scaler that can do one pre-set resolution at a time. The VGA port can either do that (same as HDMI), or else does whatever direct resolution the core itself puts out. You would need some kind of external scaler to pull off what you want. (e.g. plug the analog side/original resolution into a Retrotink to handle one display, your HDMI out on Mister does another.)
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