Turbo-R ST 4MB Internal Memory Upgrade

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By TheRogue

Expert (116)

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19-07-2009, 02:31

Hey, I've read on various pages that it's possible to upgrade the FSA1-ST to 4MB internally, but I can't find a text that actually describes how to do it. Does anyone know where I can find the information to do this? Thanks guys!

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By SaebaMSX

Hero (533)

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19-07-2009, 08:23

Even if I know that some Dutchies have this upgrade inside their turboRs (at least for GTs) I would not recommend it. Some software won't work because they don't have an accurate memory search, so be careful with it. If you still need this mod just add a switch to select it (2/4mb).

The upgrade to 512KB is very easy so I would go for it if I were you. Of course, I already have this mod in my ST. Tongue

Anyway maybe you could find something in MSX Info Pages (512KB and 1MB) MemoryAndMappers

By msd

Paragon (1318)

msd's picture

19-07-2009, 10:11

Please don't say that. 4MB works just fine. I have it for years and you don't need a switch. The only problem I had was unkown reality,but that was easily fixed. You probably never owned 4MB SaebaMSX and probably never even seen software fail on this.

By RyJuZo

Master (236)

RyJuZo's picture

19-07-2009, 11:43

Please don't say that. 4MB works just fine. I have it for years and you don't need a switch. The only problem I had was unkown reality,but that was easily fixed. You probably never owned 4MB SaebaMSX and probably never even seen software fail on this.

I was wondering ...how do you use your 4mb ??

meaning what software uses the whole 4mb ?

By wolf_

Ambassador_ (9629)

wolf_'s picture

19-07-2009, 12:04

Nothing, only stuff like sampling software, or maybe some video tools, dunno. But in any case software where the user decides how much media to use.

Most Japanese MSX software runs on 64KB, most European software runs on 128k. Exceptional games or demos require 256KB, and 512KB is rare.. Meridian could use it: the more mem the more patterns, and I think SymbOS also likes to have a bit more memory.

By msd

Paragon (1318)

msd's picture

19-07-2009, 12:10

Dos2.0 can use it allBig smile

By Manuel

Ascended (13891)

Manuel's picture

19-07-2009, 12:25

Software that reads the mapper registers to find out the amount of RAM (which is WRONG) will only read back 512kB on turboR anyways, because only the first 5 bits are connected, which means you can only discover 32 (amount of 5 bits)*16kB (block size) = 512kB...

I'd say: no problem at all to connect 4MB. Software with bad RAM detection won't fail (but will only find 512kB) and good software will find all 4MB.

By PlainSpooky

Resident (41)

PlainSpooky's picture

19-07-2009, 14:38

My FS A1ST has a internal 1024Kb of RAM (using a 30 pin memory module) and a switch key to change between 1Mb and 256Kb just for programs that reads mapper registers. And I think that a internal 4Mb isn't possible because a limitation of S-1990 IC.

By msd

Paragon (1318)

msd's picture

19-07-2009, 15:04

Do you ever use that switch?

By TheRogue

Expert (116)

TheRogue's picture

19-07-2009, 20:06

My Turbo-R already is upgraded to 512k internal, I wanted to do the 4MB upgrade because I read that 4MB is the largest amount that DOS2 can address. MSD, do you have the info on how to do it for an ST? Thanks alot!

By msd

Paragon (1318)

msd's picture

19-07-2009, 20:36

No I didn't. As far as I know 1MB is indeed the maximum that the s1990 can handle.

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