Search found 99 matches
- Tue Jun 16, 2020 8:47 pm
- Forum: Website Discussions
- Topic: Great to be back
- Replies: 19
- Views: 2545
Re: Great to be back
Thanks for fixing the site... Was a little worried it might never return.
- Tue Jun 16, 2020 8:46 pm
- Forum: Hardware
- Topic: 1040 STf with scrolling problem
- Replies: 7
- Views: 956
Re: 1040 STf with scrolling problem
It looks like the video address is being updated, but the overscan routines aren't working. That would mean the video address register isn't being updated, so the CPU cannot synchronize itself with the video state-machine. And if my memory serves, the currently fetched video data address lives in th...
- Thu Dec 19, 2019 2:34 pm
- Forum: 680x0
- Topic: Understanding the Union Demo's Opening of left and right borders
- Replies: 37
- Views: 8595
Re: Understanding the Union Demo's Opening of left and right borders
The quoted statement makes no qualitative claim about Ijor’s English at all, and indeed there are no grounds on which to do so. I can’t fault it, and haven’t. This is my first comment on it at all. I'm glad that was a misunderstanding. “The table below lists the times at which certain tests are app...
- Thu Dec 19, 2019 1:12 am
- Forum: 680x0
- Topic: Understanding the Union Demo's Opening of left and right borders
- Replies: 37
- Views: 8595
Re: Understanding the Union Demo's Opening of left and right borders
In a conversation where each of us has repeatedly misunderstood the other, I don't know how helpful it is to start picking at language now that there seems to be some clarity Ijor's English is much better than is being suggested above. And Ijor knows what he is talking about since he reimplemented ...
- Thu Nov 15, 2018 3:06 am
- Forum: News & Announcements
- Topic: FX68K Cycle accurate 68000 core
- Replies: 56
- Views: 29699
Re: FX68K Cycle accurate 68000 core
This is really cool 
I'm curious, are the ROMs (mem files) taken from the decapping you did?
Or, if they're custom, do you have some tool to generate them rather than typing them in in binary? (in the dark ages before I had an assembler, I used Hex...)

I'm curious, are the ROMs (mem files) taken from the decapping you did?
Or, if they're custom, do you have some tool to generate them rather than typing them in in binary? (in the dark ages before I had an assembler, I used Hex...)
- Thu Oct 25, 2018 1:09 am
- Forum: MiSTer
- Topic: FX CAST Atari ST core
- Replies: 336
- Views: 170578
Re: FX CAST Atari ST core
Hi Alien, does it also emulate the 6301? (For example, does the Froggies over the Fence 6301 code I wrote run on it?). Yes. And does 4 bit hardscroll work on it? I'm guessing it does, but could you confirm? Yes. Your demo runs fine :) What about sound (full YM emulation?). Every PSG feature is impl...
- Thu Oct 25, 2018 1:03 am
- Forum: MiSTer
- Topic: FX CAST Atari ST core
- Replies: 336
- Views: 170578
Re: FX CAST Atari ST core
I'm curious: does it also emulate the 6301? (For example, does the Froggies over the Fence 6301 code I wrote run on it?). And does 4 bit hardscroll work on it? I'm guessing it does, but could you confirm? What about sound (full YM emulation?). And how does it do wakestates? Yes, I know, I'm thinkin...
- Wed Oct 24, 2018 4:37 am
- Forum: MiSTer
- Topic: FX CAST Atari ST core
- Replies: 336
- Views: 170578
Re: FX CAST Atari ST core
Hi Ijor, this sounds quite amazing! :D I'm curious: does it also emulate the 6301? (For example, does the Froggies over the Fence 6301 code I wrote run on it?). And does 4 bit hardscroll work on it? I'm guessing it does, but could you confirm? What about sound (full YM emulation?). And how does it d...
- Fri Sep 07, 2018 4:14 am
- Forum: Demos - General
- Topic: Parallax Distorter 2
- Replies: 32
- Views: 24983
Re: Parallax Distorter 2
Congratulations on your demo sigge! Very impressive first release. Funny you mention no graphics artists, Ajrarn & I were in a group "the Technocrats" but never released anything for the same reason. Then we joined up with ST Connexion and Krazy Rex & ATM gave us bitmaps to make our code sparkle :D ...
- Wed Aug 01, 2018 12:58 am
- Forum: Hardware
- Topic: The SECRET VIDEO MODE in an ST: 400 lines in COLOR (and with 72 Hz)!
- Replies: 95
- Views: 30889
Re: The SECRET VIDEO MODE in an ST: 400 lines in COLOR (and with 72 Hz)!
Random crazy thought: if one had a monitor which supported a 30Hz refresh rate... one could perhaps do this switch at some point when the screen in low/midrez ends, delay vsync and get a 16 colour 500 and some line screen. Good for displaying static pictures... 8) The fact one would only turn off ou...
- Sun Jul 29, 2018 11:33 pm
- Forum: Coding
- Topic: Different SHIFTER versions
- Replies: 65
- Views: 19198
Re: Different SHIFTER versions
Here are a few quick video captures (50Hz, no sound, direct ST RGB feed). All done on same MB with -38 and re-verified to run OK with -38A. Unfortunately I didn't log the respective wakestates. PYM: Also checked with an IMP shifter on the board used above, but that one doesn't behave nice with a no...
- Sun Jul 29, 2018 10:53 pm
- Forum: Hardware
- Topic: Beginning of very long journey
- Replies: 264
- Views: 89517
Re: Beginning of very long journey
Double plus good!
- Thu Jul 05, 2018 11:05 pm
- Forum: Coding
- Topic: Different SHIFTER versions
- Replies: 65
- Views: 19198
Re: Different SHIFTER versions
I'd like to see the effect too. Thanks!
- Sat Jan 13, 2018 4:21 am
- Forum: Games - General
- Topic: Enchanted Land parallax scroll
- Replies: 21
- Views: 11122
Re: Enchanted Land parallax scroll
An amusing fact for Troed: If I recall correctly, they actually had adaptive code to vary the timing of the the resolution/frequency switches around, just in case there was an Atari out there that had different timings. They read the video counter to see whether the desired line lengths had been obt...
- Mon Oct 17, 2016 1:27 am
- Forum: Coding
- Topic: Quiz of the week: Single cycle accuracy code.
- Replies: 18
- Views: 8740
Re: Quiz of the week: Single cycle accuracy code.
Don't think there is any way. The Video Pointer at MMU is just a counter. The only other function besides incrementing is that Vsync edge provokes the higher bits to be reloaded from Vbase and the lower bits cleared. So only possible way seems to be to provoke a Vsync edge ... Interesting. We'd nee...
- Sun Oct 16, 2016 6:07 pm
- Forum: Coding
- Topic: Quiz of the week: Single cycle accuracy code.
- Replies: 18
- Views: 8740
Re: Quiz of the week: Single cycle accuracy code.
For some reason, when you asked this question, it brought to mind that I always wondered whether there might be a way to change the video fetch address mid-screen. I tried to find a means in software, but never succeeded. That's something you could check when you decap/reverse-engineer the MMU. If t...
- Thu Aug 18, 2016 3:01 pm
- Forum: Hardware
- Topic: MMU schematics WIP
- Replies: 48
- Views: 14839
Re: MMU schematics WIP
Btw, this is one of the problems of using a delay chain. It is variable and not completely reliable. The delay would depend on the board temperature. I wonder if this is one of the reasons of the Shifter weird issues observed depending on the warming (wake substates, as Troed call them). Might be. ...
- Sun Jul 17, 2016 3:53 am
- Forum: Coding
- Topic: ST Chipset decap
- Replies: 144
- Views: 96881
Re: ST Chipset decap
Hi ijor, I'm curious whether you've had any chance to learn anything new on this topic since your last update.
- Sun Jul 17, 2016 3:45 am
- Forum: News & Announcements
- Topic: *** R-TYPE DELUXE SOURCE CODE ***
- Replies: 29
- Views: 22169
Re: *** R-TYPE DELUXE SOURCE CODE ***
Thanks Bod/Stax, even though you can't read this.
- Mon May 30, 2016 12:40 am
- Forum: Hardware
- Topic: Resourced TOS Rom
- Replies: 47
- Views: 13310
Re: Resourced TOS Rom
It makes sense they only got EmuTos working for monochrome mode: the Amiga can't do the type of bitplane interleaving the Atari ST uses, but there's only one bitplane in high-rez. Troed is right. Most games turn off the OS since TOS was notoriously slow. I remember using a "SoftBlitter" which replac...
- Mon May 30, 2016 12:03 am
- Forum: Coding
- Topic: ST Chipset decap
- Replies: 144
- Views: 96881
Re: ST Chipset decap
I may be misremembering, but I also think it didn't always work, whereas the the above code did force the Shifter to reset as I wanted reliably. Perhaps RESET only clears the IR registers at certain points? You are (partially) right! Yes, hardware reset might not perform actually a clean Shifter re...
- Fri May 27, 2016 8:00 pm
- Forum: Coding
- Topic: ST Chipset decap
- Replies: 144
- Views: 96881
Re: ST Chipset decap
Ah, not exactly switches, but whole frames at each rez. I missed that. But if you can spend so much time, then it might be better to execute the RESET instruction. That is guaranteed to work. Of course, it is much more invasive as will affect things that you might prefer to avoid. I also had some "...
- Fri May 27, 2016 4:09 am
- Forum: Coding
- Topic: ST Chipset decap
- Replies: 144
- Views: 96881
Re: ST Chipset decap
FWIW, here is the shifter reset code from my article:
reset_shifter:
move.l #$VBL_routine, $70.w
moveq #5,d0
loop:
move.b #1, $ffff8260.w
stop #$2300
clr.b $ffff8260.w
stop #$2300
dbra d0, loop
rts
VBL_routine:
rte
reset_shifter:
move.l #$VBL_routine, $70.w
moveq #5,d0
loop:
move.b #1, $ffff8260.w
stop #$2300
clr.b $ffff8260.w
stop #$2300
dbra d0, loop
rts
VBL_routine:
rte
- Wed May 25, 2016 5:31 pm
- Forum: Demos - General
- Topic: Atari Demoscene
- Replies: 58
- Views: 69312
Re: Atari Demoscene
Very nice!Askja wrote:Hi all,
After some months of work, I just finished my giant picture with all the Atari Demoscene!
Enjoy!!![]()
http://undead-factory.fr/demoscene/index.html
- Sat May 14, 2016 9:36 pm
- Forum: Demos - General
- Topic: Now on Kickstarter: The Atari ST Anthology book volume 1
- Replies: 20
- Views: 32182
Re: Now on Kickstarter: The Atari ST Anthology book volume 1
Ok, Ich könnte vielleicht mit dem zweiten Teil helfen... ich könnte zB eine Verbindung herstellen mit den Franzosen, mit denen ich noch Kontakte habe. Welche Produkte populär waren, hat meiner Meinung nach mehr damit zu tun, in welchem Land man in den 90ern lebte. Hannover ist nicht in der Nähe von ...