Author Topic: Atari STE overscan?  (Read 6508 times)

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Offline Anemos

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Atari STE overscan?
« on: 09-03-2015, 16:45:12 »
Is it possible to remove the border from the STE and desktop/program/games displayed in overscan?

My system: Atari STE 4MB, OS: SuperTOS 2.06, HD: US/disk 4gb SDcard ,ppera v0.98 HD drivers, USB mouse adapter by me, PSX controller joy adapter by me,  full list of adaption,s games by Petari.
Second Atari machine: 1040 STF
Other: 2X Lilliput Atari 130 XE


Offline Petari

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Re: Atari STE overscan?
« Reply #1 on: 09-03-2015, 16:59:00 »
Overscan is possible, and is done already.  But you can not remove border completely.
I made overscan mod in ST - it is very simple - just one switch.   Should work with STE too, but I never tried.
SW overscan is possible too - may see in some games, demos, even in some my videos, but it may take some CPU time, or lot of CPU time.

Why that sudden interest now, decades later ?   :)

Offline Anemos

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Re: Atari STE overscan?
« Reply #2 on: 09-03-2015, 23:19:25 »
Its just a question of my team, :D ,if possible to show us your mod, then you got a time.
thanks.
My system: Atari STE 4MB, OS: SuperTOS 2.06, HD: US/disk 4gb SDcard ,ppera v0.98 HD drivers, USB mouse adapter by me, PSX controller joy adapter by me,  full list of adaption,s games by Petari.
Second Atari machine: 1040 STF
Other: 2X Lilliput Atari 130 XE

Offline Petari

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Re: Atari STE overscan?
« Reply #3 on: 10-03-2015, 08:38:38 »
HW overscan used in ST machines is unfortunatelz not usable in STE - because Glue and MMU are integrated in 1 chip.
Circuit for ST is:   

Offline ataricrypt

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Re: Atari STE overscan?
« Reply #4 on: 10-10-2015, 17:45:55 »
Hi guys, with regards to a software method of removing borders, I recently "discovered" two old utils that sit inside the AUTO folder and remove the bottom border (and also supporting interlace as well). One is surprisingly called 'NoBorder" by New Core and the other Remove15.prg by Christian Dahl. The latter is apparently his modification of another program, but I couldn't seem to find out any information about what...

Anyhow, both are tiny and fit into the AUTO folder of a bog-standard Atari STe for a bigger GEM desktop.
I did get REMOVE15.PRG working on my Mega STE, but it suffered a little flicker.. unless I was in 8mhz mode, but that defeats the point of me buying a 16Mhz STe - lol - Still, it was nice to see ST LOW/MEDIUM with more vertical resolution.

Especially interesting was the Interlace mode, but obviously flickery as hell. Go 60Hz for that!
I actually quite enjoyed writing in Everest yesterday using this enhanced ST Medium resolution ;-)

I couldn't find any downloads but I'll be happy to pass on these two files if anyone's interested? np

Steve

ps, I'd love to know if there are other software methods of expanding the GEM desktop size.
Anyone know of any? Especially ones that are Mega STE happy too of course. TIA
AtariCrypt . . stay cool & stay ATARI ST
Atari MEGA STe | Atari STe | MiNT OS 1-19 Aranym OS X

Offline Petari

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Re: Atari STE overscan?
« Reply #5 on: 13-10-2015, 10:43:44 »
Unfortunately, given schematic is good only for ST, not for STE machines. Problem is that DE signal is not accessible on STE.
Considering SW methods: expanding vertical resolution is possible at low CPU load, but expanding horizontal one is almost impossible in SW, and will cost lot of speed (CPU time).
Ataricrypt:  please post those two files, I would like to take look. If having problems where to upload them, you may attach them in e-mail to me.

Offline ataricrypt

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Re: Atari STE overscan?
« Reply #6 on: 13-10-2015, 13:59:21 »
No problem, I'll email them shortly :-)
Steve
AtariCrypt . . stay cool & stay ATARI ST
Atari MEGA STe | Atari STe | MiNT OS 1-19 Aranym OS X

Offline ataricrypt

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Re: Atari STE overscan?
« Reply #7 on: 13-10-2015, 19:32:20 »
Hi, did you get the email? I sent it a few hours ago..
Steve
AtariCrypt . . stay cool & stay ATARI ST
Atari MEGA STe | Atari STe | MiNT OS 1-19 Aranym OS X

Offline Petari

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Re: Atari STE overscan?
« Reply #8 on: 14-10-2015, 10:43:27 »
Got it. There are even some sources. so very useful. Thanx.
I don't know where will have time to deal with it, just some things to note:  interlaced will flicker always. Vertical overscan in SW may fail in case of disk (floppy) access because DMA will screw sensitive timings, but will be OK right after disk access stops.
Maybe is worth  to  make SW for scrollable expanded screen, where only part is visible. I made already long time ago such mono-emulator, with real res of 640x400, from what 200 lines were visible, and when user approached top or bottom with mouse it scrolled. That was little slow, because need to copy lot of RAM. But on STE you can do it without any RAM copy. So, something like 320x400 in low res, 640x400 in medium, or even wider, so for instance 1280x400 in medium res. Good thing with it would be that no timing tricks will be used, so no speed loss, floppy access sensitivity.

Offline ataricrypt

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Re: Atari STE overscan?
« Reply #9 on: 14-10-2015, 16:55:03 »
Ah that makes sense, thanks. I did notice the flicker as it was loading from my hard drive or flipping directories etc.etc..
And whatever STE mods get made from these ideas / apps then GREAT. I look forward to it :)
AtariCrypt . . stay cool & stay ATARI ST
Atari MEGA STe | Atari STe | MiNT OS 1-19 Aranym OS X

Offline sasa

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Re: Atari STE overscan?
« Reply #10 on: 19-10-2015, 02:41:51 »
ataricrypt@ please send me on: atarif030@gmail.com
thanks