Graphic glitches MiST Atari core

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BCH
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Graphic glitches MiST Atari core

Postby BCH » Sun May 07, 2017 11:45 pm

Hello everyone!

I've been playing around with my home-made MiST (bought a bare board and I assembled it myself). Everything is quite ok, all cores I've tried seems to work well.

When using the Atari core I've noticed some graphic glitches when loading some of the Automation disk images. These very same images work well with an emulator (Hatari) but when loaded on the MiST I get somehow a "shifted-colors" screen. Here is an example:

Here is the screenshot from the emulator:
Image
and this one is a picture of the MiST video output:
Image

I wonder if this is a normal MiST behavior or maybe my board is not 100% working?

I'll appreciate any insight

Cheers!
Last edited by BCH on Mon May 08, 2017 8:31 am, edited 1 time in total.

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Estrayk
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Re: Graphic glitches MiST Atari core

Postby Estrayk » Mon May 08, 2017 1:34 am

What Tos are you using?
・Falcon 030+FPU 14mb CosmosEX・Atari MegaSTE 4Mb CosmosEX・Atari STe 4Mb GotekHxC+Satan・Amiga A600 Vampire V2・Amiga A1200 030/50・MIST・

BCH
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Re: Graphic glitches MiST Atari core

Postby BCH » Mon May 08, 2017 8:24 am

In both cases (the MiST and the emulator) Im running it as Atari ST with blitter and TOS 1.02

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Re: Graphic glitches MiST Atari core

Postby ericgus » Mon May 08, 2017 3:37 pm

BCH wrote:In both cases (the MiST and the emulator) Im running it as Atari ST with blitter and TOS 1.02


NTSC or PAL TOS?

BCH
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Re: Graphic glitches MiST Atari core

Postby BCH » Mon May 08, 2017 3:49 pm

ericgus wrote:
BCH wrote:In both cases (the MiST and the emulator) Im running it as Atari ST with blitter and TOS 1.02


NTSC or PAL TOS?

I belive Im using the UK TOS so it should be PAL. I would have to recheck this.

Which of the two (NTSC or PAL) should be the best option?

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Re: Graphic glitches MiST Atari core

Postby Greenious » Mon May 08, 2017 5:07 pm

PAL usually is the better choice. PAL 50hz screen refreshrate give more time to do things than NTSC 60hz.
Updated my guides as of june 28th, 2016. Check'em out and feedback!
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Re: Graphic glitches MiST Atari core

Postby WoodlandSpirit » Mon May 08, 2017 7:14 pm

I'm new to the stuff with MIST developments although the way I'm seeing it I don't know how this could be the same problem but this issue hits me as the same sort of issue a number of Automation menus have/had with STE based hardware.

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Re: Graphic glitches MiST Atari core

Postby BCH » Mon May 08, 2017 10:26 pm

I just find a mention that might be some graphic glitches due the CPU core:

http://atari-forum.com/viewtopic.php?f= ... 25#p285916

The post is old so I dont know if the issue was fixed later on or not...

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Re: Graphic glitches MiST Atari core

Postby vebxenon » Tue May 09, 2017 7:00 am

This core must be updated...

BCH
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Re: Graphic glitches MiST Atari core

Postby BCH » Tue May 09, 2017 2:14 pm

vebxenon wrote:This core must be updated...


So you think these glitches on some Automation loading screens are due the 68000 implementation on the mist core?

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Re: Graphic glitches MiST Atari core

Postby SLiX » Tue May 09, 2017 3:44 pm

Hi BCH,

as you could read it somewhere on this forum, the Atari ST core does not achieve "exact timings" required to get some "tricky" Atari ST code to work correctly (lots of demo stuff are messed up).

Most emulators are able to get exact timings because they are "full software" implementations, and so it is possible to easily synchronize differents "virtual" components. This is more difficult in a FPGA, where some real clock signals are created and used, as there are some constraints on frequencies to get an exact one.

This is probably the reason of your graphic glitches. I regularly use the Atari ST core, and there are lots of them.

Hope this could helps,
SLiX.

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Re: Graphic glitches MiST Atari core

Postby BCH » Tue May 09, 2017 10:11 pm

SLiX wrote:Hi BCH,

as you could read it somewhere on this forum, the Atari ST core does not achieve "exact timings" required to get some "tricky" Atari ST code to work correctly (lots of demo stuff are messed up).

Most emulators are able to get exact timings because they are "full software" implementations, and so it is possible to easily synchronize differents "virtual" components. This is more difficult in a FPGA, where some real clock signals are created and used, as there are some constraints on frequencies to get an exact one.

This is probably the reason of your graphic glitches. I regularly use the Atari ST core, and there are lots of them.

Hope this could helps,
SLiX.


Thanks for the answer. I just wanted to make sure my home-made MiST was working as supposed.
I wasnt aware the core does not achive exact timings. Nevertheless, and besides these glitches, most software I've tried works well so hats off to the developers!

Cheers

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Re: Graphic glitches MiST Atari core

Postby vebxenon » Wed May 10, 2017 10:44 am

SLIX has done the answer :-)

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Re: Graphic glitches MiST Atari core

Postby vebxenon » Wed May 10, 2017 10:48 am

Last core update was done 11 months ago. core_160603.rbf

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Re: Graphic glitches MiST Atari core

Postby WoodlandSpirit » Wed May 10, 2017 12:25 pm

I tried a few things to see if I could get the same result in an emulator but alas this is not a problematic menu in particular, the timings thing would make sense as to why this menu is displaying the same sort of issue I've seen on other menus via STE systems.

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Re: Graphic glitches MiST Atari core

Postby WoodlandSpirit » Wed May 10, 2017 12:25 pm

EDIT: Double post

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Re: Graphic glitches MiST Atari core

Postby nightshadowpt » Thu Sep 07, 2017 3:32 am

Just one question. Is this problem a limitation of the MiST that cannot be overcome, or is it just a matter of updating the core to support exact timings?

Thanks


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