If anyone wants a project..

General discussions or ideas about hardware.
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exxos
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If anyone wants a project..

Post by exxos »

http://atari4ever.free.fr/#ram

16MB RAM board for every ST.


Never seen one or heard of it being done.. Though probably a H4 project to use a 16mb simm. It also decodes TOS 206 but might be avoidable doing that part.

From what I can tell it generates MAD10 and fools the GLUE on address ranges. I assume to fool the MMU into thinking its accessing valid ST-ram when its actually accessing higher ranges.
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Icky
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Re: If anyone wants a project..

Post by Icky »

I havent heard of anyone doing this either. Here is the main schematic.

TABPlus.png
TABPlus.png (97.5 KiB) Viewed 4133 times
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exxos
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Re: If anyone wants a project..

Post by exxos »

Never seen any info of images of it either. Would think the bulk of the logic could go in a GAL.
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frank.lukas
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Re: If anyone wants a project..

Post by frank.lukas »

There was a 16MB (15MB) real ST Ram extension. It works by doing bank switching. Eight 2MB banks are possible ...

-> https://forum.atari-home.de/index.php?topic=13517.0
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rubber_jonnie
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Re: If anyone wants a project..

Post by rubber_jonnie »

Like I need another project....
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
terriblefire
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Re: If anyone wants a project..

Post by terriblefire »

rubber_jonnie wrote: Wed Apr 08, 2020 8:00 pm Like I need another project....
Happy to route anything anyone sets up in eagle. Right now I’m going nuts
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indicates how much hurting you shall receive."
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Re: If anyone wants a project..

Post by Icky »

You might regret that offer @terriblefire :)
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PhilC
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Re: If anyone wants a project..

Post by PhilC »

H4 Mega ST version @terriblefire ? :lol:

I guess the pcb is the easy but in this case, it's the software to make it all work afterwards.
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exxos
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Re: If anyone wants a project..

Post by exxos »

frank.lukas wrote: Wed Apr 08, 2020 6:27 pm There was a 16MB (15MB) real ST Ram extension. It works by doing bank switching. Eight 2MB banks are possible ...

-> https://forum.atari-home.de/index.php?topic=13517.0
~Interesting that someone else did similar solution then. So TOS may need patching to see the full RAM, but no great surprise. I also wonder how the TAB board also got around this issue as it just seems to mention using TOS206.. I guess lack of information there is the issue.

Though I half recall suska gave 14MB ST RAM, but not sure, think that was TOS206.
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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exxos
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Re: If anyone wants a project..

Post by exxos »

terriblefire wrote: Wed Apr 08, 2020 8:14 pm Happy to route anything anyone sets up in eagle. Right now I’m going nuts
There is the DRAM board I mentioned a couple weeks ago if you wanted a board to route.. This one would be 68k footprint pretty much PLD and DRAM. As it would be 68k, no use in any DRAM over 16mb as we can only really use 4mb - 14mb range for alt-ram anyway. I did get the xlinix chips, don't think I decided on a RAM yet though. RAM would need to be quick to use up to 60mhz CPU. Such a board would plug right into a H4. The 5v sram ones I designed end up costing towards £100 mark.. Its why I wanted some help with your dram controller stuff to design a cheaper board.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
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