Dual ANTIC upgrade?

[Gunstar]

First off, I jsut want to state that I'm sure that this IS possible, but admit that it may take a special circuitboard with one or both ANTIC chips on it (or one on the new board and one on the motherboard) in order to throw a switch to choose between NTSC and PAL Antic chips (And please don't mention the PAL GTIA I'm fine without it for my purposes). I was thinking that I might first just try piggy-backing NTSC&PAL ANTIC's and just connect a switch to their VCC and ground connection to see if that will work. I was told once that this wouldn't work, but I've been told a lot of things wouldn't work in the past and I tried anyway and proved the nay-sayers wrong. But I'm just posting here to see if anyone has done such a modification, and how they did it. I'm willing to do whatever it takes, but am hoping it will be as simple as a piggyback.

Edited June 21, 2005 by Gunstar

[analmux]

It depends on whether you want to let them run simultaneously. If you're system is hooked up up a PAL monitor then I can imagine that you want to turn off the NTSC antic and vice versa. Then you don't have to make a complicated circuit board. Just piggyback them would work I think.

 

Only one thing: (see Clockspeed Difference thread)

you might need to add a second clock crystal to the main board

Edited June 22, 2005 by analmux

[Bryan]

I wouldn't try putting an Antic in a live system with it's power pins disconnected. I'm sure it wouldn't last long. What you need is a way to isolate the unwanted Antic from the bus. You may be able to do this by pulling down its reset pin (and possibly stopping the clock input).

 

-Bry

[Goochman]

Just curious on what gains one would expect with 2 Antics in a system?

[Bryan]

He's talking about being able to switch between a 50 and 60Hz display. I did some tests with Antic a while back and seem to remember that if you hold one of them in reset and stop the clock input, it leaves the bus pins tri-stated, which might allow 2 of them to be piggy-backed.

 

(I seem to recall that it will glitch the bus every cycle if the clock isn't stopped too, but don't hold me to any of this.)

 

-Bry

Edited June 22, 2005 by Bryan

[Gunstar]

It depends on whether you want to let them run simultaneously. If you're system is hooked up up a PAL monitor then I can imagine that you want to turn off the NTSC antic and vice versa. Then you don't have to make a complicated circuit board. Just piggyback them would work I think.

 

Only one thing: (see Clockspeed Difference thread)

you might need to add a second clock crystal to the main board 

878799[/snapback]

 

I'm using a Commodore 1084S monitor which is compatible with both 50 and 60hz. Yes, I only want one Antic working at a time, as Bryan stated, it's just to switch between 50/60hz. I'm just attempting to get to a point where I don't have to have both my XL and XE hooked up and sitting on top of each other just so I can play PAL games with a 50hz display and NTSC games with a 60hz display. I hate NTSC games on PAL display becuase of the way it squishes the display, not to mention the flickering which I'd just as soon do without if I'm not playing a PAL game. But I love both PAL and NTSC games, have both and need both a PAL Antic and an NTSC Antic. I'd just like to do a mod to get them both in one machine. I'm currently upgrading my 1200XL to 1meg, and have already done many other upgrades and fixes to it, and want to make it my main Atari machine, but not if I have to settle for a 50hz display all the time. As for the clock speed difference, I'm not concerned with that too much for my needs, I've only changed out the NTSC ANTIC with a PAL in my NTSC computer, and it has worked perfectly that way for my needs in running the PAL software I want to run. All I want is the ability to change between the 50/60hz display and clock speed be damned. I'm not looking for a "perfect" mod here, what I have already done works fine for me, what few problems I may encounter at some point I can live with (I haven't encountered any yet, and use dozens and dozens of PAL games).

 

I also very much appreciate the suggestions that have been made, and they are all thing for me to consider when I attempt this mod, but I'm really hoping to find someone who actually has done a dual ANTIC (PAL/NTSC) mod, I'm sure there must be somebody out there who has, it's certainly not impossible and there are some good advantages. But theories aren't much good to me, I can try out theories on my own. I know the facts about the clock differences and GTIA flag, etc, but for my purposes, these, as of yet, have not been a concern, and since I don't intend to use many more PAL programs than those that I already KNOW work fine with my setup, I highly doubt they will become a concern, if they ever do, then I can think about changing out the GTIA or doing a dual GTIA and clocks at some point in the future. I will forge ahead at this time, with what I know and the suggestions given here, and see what happens, but I'd still like to hear from someone who has already done something like this. If I'm the first, then I guess once I'm successful (which I eventually will be one way or the other; even if I have to add in new crystals and GTIA, etc.) then I guess I'll be the one showing the way for others with mod instructions.

Edited June 23, 2005 by Gunstar

[ndary]

gunstar,

 

in the past i made a dual antic (pal/ntsc) computer and it worked

 

Nir

[analmux]

This isn't about a dual NTSC+PAL antic upgrade, but maybe you can get ideas from reading these:

 

http://www.atariage.com/forums/index.php?s...opic=32173&st=0

 

http://www.atariage.com/forums/index.php?s...opic=32599&st=0

[carmel_andrews]

gunstar,

 

in the past i made a dual antic (pal/ntsc) computer and it worked

 

Nir

879319[/snapback]

 

 

All these dual Atic/Gtia upgrades, are they essentially basd on or designed around the BOB WOOLEY original dual antic upgrades of the late 80's (the one that i read about in Atari user and Pg 6)

 

I remember that the BW upgrade gave you 4096 colours

 

Is BW still with us and in the land of the living or has he defected to a rival computer brand (CBM, Amstrad, Sinclair etc)

 

Also if you read the disk version of the atari hardware notes (BOB DU HAMEL) and also the technical reference manual, they make mention of the possibilities of transplanting multiple Antic/G/CTIA and pokey chips into a standard A8 system

 

So, my guess is that all these Atari h/w hackers have being delving into the above mentioned texts

 

It saddens me that that the publisher of these texts (atari themselves) never got around to performing/producing such upgrades (officially) or explaining to users how to do it

 

End of pitch

[analmux]

All these dual Atic/Gtia upgrades, are they essentially basd on or designed around the BOB WOOLEY original dual antic upgrades of the late 80's (the one that i read about in Atari user and Pg 6)

 

I remember that the BW upgrade gave you 4096 colours

 

Is BW still with us and in the land of the living or has he defected to a rival computer brand (CBM, Amstrad, Sinclair etc)

 

Also if you read the disk version of the atari hardware notes (BOB DU HAMEL) and also the technical reference manual, they make mention of the possibilities of transplanting multiple Antic/G/CTIA and pokey chips into a standard A8 system

 

So, my guess is that all these Atari h/w hackers have being delving into the above mentioned texts

 

It saddens me that that the publisher of these texts (atari themselves) never got around to performing/producing such upgrades (officially) or explaining to users how to do it

 

End of pitch

 

To be honest, I've never heard before of the BW antic upgrades.

 

My first inspiration for my 2nd Antic+gtia project was the TIP graphics mode: mixed GTIA 9 + 11 graphics to get 256 colors. odd lines were gr. 11 to give the color hue, and gr. 9 lines (even lines) got mixed with gr. 11 colors (PAL decoder effect). Then I started thinking: what if we have the first antic+gtia circuit displaying odd lines (mixed gr. 9+11), and then the second antic+gtia circuit displays the even lines and let a switching circuit choose from which antic+gtia circuit the signals will be let through to the TV output hardware.

 

I was mistaken: I thought the GTIA had some kind of internal color buffer to memorize the color hues of previous lines, but it's inside the TV or monitor where this is stored (somehow, I don't know how ).

 

2nd mistake: The color/lum signals were digital, whereas I thought the color signal was an analogue signal, but that's only AFTER it gets through the TV decoder.

In fact color signal is more like a retarded squarewave (digital). Therefore I thought I would need an Analogue Multiplexer to select from the color signals of the separate antic+gtia circuits. (that explains my name).

 

That was just theory: later I found out that I'd better only multiplex luma signals (I knew these were digital) and stepped off the idea of multiplexing the signals on odd/even lines, and thought it would be better to mix the signals: hue signals from 1st circuit and luma signals from 2nd circuit. Then let the first circuit provide color information (like colorcells on C64) and the 2nd circuit provided shades (contrast).

 

That's the story behind my upgrade.

 

.....

I still wonder how BW did 4096 colors:

4096 = 16 * 256, so maybe he used the luma of the 2nd gtia in combination with the luma of the 1st gtia:

 

Luma determines the amplitude of the (combined) color signal TV output, so the (normally) 4bits luma output must be converted from digital -> analogue. This is done by using resistors of 8, 4, 2, 1 (k)ohm. Maybe the 2nd gtia luma output was connected to different resistors (1/2, 1/4, 1/8, 1/16 (k)ohm) to provide a finer shade spectrum. This will finally give 4096 colors: 16 hues times 256 shades.

Edited June 23, 2005 by analmux

[Heaven/TQA]

mux, still want one... could be fun to code...and maybe there is a way to enhance existing games with small benefits of your upgrade... like GB & GBC software...

[carmel_andrews]

mux, still want one... could be fun to code...and maybe there is a way to enhance existing games with small benefits of your upgrade... like GB & GBC software...

879418[/snapback]

]

 

 

 

I don't know how BW got 4096 colours out of his u/g, i am just going by what i recall about the article that was in either pg 6 or atari user

 

like i said earlier, i am surprised that atari didn't seize the opp't. to doing this type of u/g officially themselves, unfortunately Atari's management dropped the ball and allowed their competition to come up with similar concepts for their 8bit offerings, ones that come to mind are the later incarnation of the 64 and also the Amstrad 'PLUS' and 'GX' computuer/games systems

 

The commodore one incorporated an enhanced or extended version of the VIC/SID chip set, which gave amiga style 4096 colour range and hi rez gfx modes like 800 by 600 (can't remember exactly) additionally the sid chip had stereo sound capability and the system came with a 3.5' 720k disk drive (i remember that it was called the c65 or something like that), and also the Amstrad jobbie had similar capabilites like 4096 colour range, stereo sound (can't remember the gfx resolution though), if Jay Miner was alive today, he'd be turning in his grave that Atari passed up on an opp't. like this

 

There again, if memory serves me right, tramiel wasn't much of a supporter of the a8 series, which is why most of the marketing budget was spent on the ST (in the UK and EU at least anyway)

[+CharlieChaplin]

Well,

afaik the article about a double Antic/GTIA was published in Atari Classics many years ago. Someone told me it was written by Bob Woolley, someone said it was Chuck Steinman (the man that informed us about the double Pokey upgrade - stereo with two Pokey chips in one computer). Anyway, I don`t have any AC magazines, so I cannot quote this article or tell any details...

 

But, as far as I know, all the interlace modes used with R.J. Espino`s CPEGview and other gr. modes like Apac, HIP, RIP and TIP would work without any interlace with such a double Antic/GTIA...

 

Meaning 1) 320x200 pixels with 32 colors, 2) 160x200 pixels with 64 colors, 3) 80x200 pixels with 256 colors and other nice gfx tricks - all without interlace or flicker... Alas, this double Antic/GTIA upgrade seems to be a lot more complicated than the double Pokey upgrade...

 

Besides, it is not random luck that these sound and graphic upgrades are possible. Atari already "thought" of such upgraded computers, but of course when Atari had big financial problems in 1983 and 1984 and later was taken over by Jack Tramiel, all these and many other A8 projects were cancelled... -Andreas.

[Gunstar]

Yes, you are right that those "graphic modes" don't need any dual ANTIC/GTIA upgrade, but that is becuase they are "software" graphic modes; software was written to manipulate the Atari hardware's multiple modes to achieve modes beyond it's standard hardware capabilities. There was also another "software" graphic mode (I think the picture viewer was just called 'Colorview') that I used to have a paint program and a viewer (which supported stuff like GIF and the Amiga format ILBM?IBML?IMBL? whatever...) pictures and it diplayed a full 4096 colors on screen, with no hardware upgrade at all. This was done by taking 3 seperate screens of graphic mode 11 (or whatever mode is 16 shades of one color, I'm not sure offhand) of the GTIA and page-flipping through 3 screens of 16 shades of red, green, and blue (16x16x16=4096). It looked VERY good, and I specifically remember a picture of Kirk and Spock, a real photograph, that looked very good. It was, of course, 80x192 resolution, but with all those colors it still looked fantastic. I remember showing it to friends in college who laughed at my 8-bit Atari when they had Amiga's and PC's and Apple IIGS's and it blew them away, they stopped laughing at my lowly 8-bit Atari very quickly. The only trick to this mode was that you had to adjust the brightness and contrast (turned down)to get it to show up well, otherwise the picture was almost a white screen with bright&contrast at normal levels. I'd like to find these programs again. They were available on an AIM (Atari Interface Magazine) disk of the month back around '91/92.

 

Anywho, back to my dual upgrade (PAL/NTSC ANTIC). Can anyone point me in the direction of a data-sheet or at least pinout diagram of the Anitc chip(s)?

[Goochman]

For those that talk about how C= and Apple and Amstrad invested into their 8bits late in life, how many of those were really successful? I was happy Atari went the 16bit route since it gave us a wonderful new area to explore - The C128 and other Commodore 8bit computers were a drain on otherwise tight resources. Sad to see it happen but that was 1 good decision by Tramiel.

 

Now,

320x200 w/32 colors - mant that wouldve been a sight back in the day!

[pseudografx]

I got another idea how to increase the number of colours in the XL/XE without adding new Antic. My idea is that on the line between the Antic and TV modulator there would be a device that would process two consecutive frames and mix them together. I don't really know if such device would be easier to implement than a second Antic chip, but it's just another way I can think of.

The device would have been controllable via some hw register to be turned on/off. It would even be possible to mix 3, 4 or even more picutres together, which would give thousands of colours on screen in return. In such case, a hardware register should control how many consecutive frames should be mixed together.

The drawback would be that the more pictures are mixed, the lower is the possible framerate - e.g. in PAL, an image mixed out of two images could refresh 25 times per second (of course, the vertical refresh rate of TV would still be 50Hz, so no flickering would appear). Therefore such method would mainly be useful for still images or not very dynamic on-screen action.

[krupkaj]

Anywho, back to my dual upgrade (PAL/NTSC ANTIC). Can anyone point me in the direction of a data-sheet or at least pinout diagram of the Anitc chip(s)?

881506[/snapback]

Jindroush has Atari chips pinouts at his web page:

 

ANTIC

GTIA

[Gunstar]

thankyou! I did find something similiar on another page finally, but this has the pin descriptions, the other only had the picture with pin designations.

[Tickled_Pink]

All these dual Atic/Gtia upgrades, are they essentially basd on or designed around the BOB WOOLEY original dual antic upgrades of the late 80's (the one that i read about in Atari user and Pg 6)

 

And here was me thinking I was the only one who read about it. Drove myself nuts trying to find out more on the web a few years later - never did find the information I wanted.

 

I remember that the BW upgrade gave you 4096 colours

 

I always thought it was a dual GTIA upgrade.

 

Always wanted to know how Technicolour Dreams managed to get so many colours on the screen at once as well, without the use of extra hardware - counting the colour clocks as the beam went across the screen, a la 2600, and changing the palette as it went??

[Heaven/TQA]

pink, it's far more simple...

 

even scanlines = gr.9

odd scanlines = gr.11

 

so...16 colours (gr.11)*16 shades = 256 colours...without interlacing esp. on PAL machines your eye can not distingish between these 2 scanlines and will mix it up...

[Gunstar]

And then a few "view" and "paint" programs came out after Techniclor, especially in the shareware/PD realm, that took advantage of this technique and also doing full screen interlacing to get double the vertical resolution at the expense of some flickering, which looks a bit worse on a PAL than on NTSC due to the already lower scan rate of 50hz. But it's still brillaint looking stuff. I remember looking at demo disk picture shows or "slide shows" of great artwork, mostly from the U.K. and Europe, I believe. Unfortunately I lost all those disks years ago now, and am in the process of re-aquiring some of them, with some help from some good guys here. It also looks like B&C may carry many of the very disks&programs I'm speaking of in their PD library.

[carmel_andrews]

And then a few "view" and "paint" programs came out after Techniclor, especially in the shareware/PD realm, that took advantage of this technique and also doing full screen interlacing to get double the vertical resolution at the expense of some flickering, which looks a bit worse on a PAL than on NTSC due to the already lower scan rate of 50hz. But it's still brillaint looking stuff. I remember looking at demo disk picture shows or "slide shows" of great artwork, mostly from the U.K. and Europe, I believe. Unfortunately I lost all those disks years ago now, and am in the process of re-aquiring some of them, with some help from some good guys here. It also looks like B&C may carry many of the very disks&programs I'm speaking of in their PD library.

885596[/snapback]

 

 

Not wishing to Nitpick but, technicolor dream wasn't PD/shareware...it was a commercial release by red rat, I still have mine on orig. cassette format, it was the first paint programme to be released on cassette, can't remember if it was ever done on disk... demo piccies were 'ok' i suppose, nothing blinding compared to some of those euro demo's that i've seen

 

does anyone know why homesoft ditched the demo section of their (orig) atari 8bit software site, i only have demo disks upto 9x

 

Does anyone have a full version on ATR format of 'Mr Proper', it looked a good game and one of the very few that used the HIP graphics format... I believe it was one of these euro games (it's a bugger that no one in UK has come up with anything near as good... Come on Wrathchild, wer'e relying on you to take up the challenge)

[www.atarimania.com]

Does anyone have a full version on ATR format of 'Mr Proper', it looked a good game and one of the very few that used the HIP graphics format... I believe it was one of these euro games (it's a bugger that no one in UK has come up with anything near as good... Come on Wrathchild, wer'e relying on you to take up the challenge)

Mr. Proper only exists as a preview, the game was never finished.

 

--

Atari Frog

http://www.atarimania.com

[www.atarimania.com]

Not wishing to Nitpick but, technicolor dream wasn't PD/shareware...it was a commercial release by red rat, I still have mine on orig. cassette format, it was the first paint programme to be released on cassette, can't remember if it was ever done on disk...

Released on disk and even sold in the US by ICD.

 

--

Atari Frog

http://www.atarimania.com

[carmel_andrews]

Does anyone have a full version on ATR format of 'Mr Proper', it looked a good game and one of the very few that used the HIP graphics format... I believe it was one of these euro games (it's a bugger that no one in UK has come up with anything near as good... Come on Wrathchild, wer'e relying on you to take up the challenge)

Mr. Proper only exists as a preview, the game was never finished.

 

--

Atari Frog

http://www.atarimania.com

885627[/snapback]

 

 

How about if someone 'locates' the orig. coder/s, and allows wrathchild or heaven tqa to do a release version or a 'hack job' or anyone on this forum that hard codes 6502 and understands HIP graphics programming