Panasonic FS-A1GT 1024Kb RAM upgrade (or 1MB)

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By OeiOeiVogeltje

Paragon (1426)

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15-02-2010, 20:27

thanks for trying but this is not understandable english

i sent a mail just now

By Gradius2

Hero (652)

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15-02-2010, 20:43

Hi Jipe,

Please, send me to freyesm1 at gmail dot com

I wonder about those connections since is not mentioned on pdf at all.

Thanks!

By Jipe

Paragon (1594)

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15-02-2010, 21:24

Gradius2 i sent a mail
OeiOeiVogeltje i don't received it

By OeiOeiVogeltje

Paragon (1426)

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15-02-2010, 21:32

please send here

voivod---------------@-------------------------------gmail.

dot com

remove the ------------

thanks

By Latok

msx guru (3925)

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15-02-2010, 22:21

My GT is expanded to 1mb as well.......

By Jipe

Paragon (1594)

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15-02-2010, 22:26

is ok i sent it

please if you translate japanese TXT files to good english send me a copy

By Gradius2

Hero (652)

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15-02-2010, 22:48

Here is the diagram:
http://i48.tinypic.com/ws0ld.png

Here are the files converted to be able to read on PC:
http://www.mediafire.com/?jmaqkjowgjz

By Gradius2

Hero (652)

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16-02-2010, 00:10

Latok, can you tell us please, which is the correct diagram?

This one I posted here (post above), or the one in pdf (1st msg here)?

S1990 can detect until 1MB, but R800 is ready until 4MB, but not S1990.

S1990 to be able to detect 1MB you'll need to:
- A15 must be high (1)
- A14 must be low (0)
- A12 none

R800:
- A15 must be high (1)
- A14 must be low (0)

If A15 and A14 are both high, then it can detect 4MB, but not S1990 for it a special circuity is necessary, but I don't recommend above 1MB, isn't stable.

By Gradius2

Hero (652)

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16-02-2010, 01:00

I have found a text, I corrected to make it more technical:

Well, sorry if my English is not as good as I would like it to be, but translating technical French (I mean electronic words, etc) is not very easy for me ;-) anyway I did not say that Turbo R GT have 1Mb internaly, I only said that it can have it without too much hardware modification, I get this information from Japanese textfile (so writen in KANJI :-( , here is some info I did understood because they were writen in (ROMANJI = ROMAN charset and also because I have the schematic diagram of the Turbo R GT).

Between the S1990 and R800 there are three signals: A15, A14, A12. Those signal are connected to a diode named D301 via resistors R352 (A15),
R353 is not connect (A14), R354 (A12). Here is the meanning of those bits:

S1990      A15   A14   A12
            L     L     L     64Kbytes
            L     L     H    128Kbytes
            L     H     H    256Kbytes (ST)
            L     H     L    512Kbytes (GT)
            H     L     -    1Mbyte (see note 1)

R800        A15   A14
             L     L         64Kb  * 4-bit
             L     H         256Kb * 4-bit (ST/GT)
             H     L         1M    * 4-bit (see note 1)
             H     H         4M    * 4-bit

Note 1: There was KANJI in this place and I do not understand them :-( since that was the same KANJI, I think that it was to say that they will use this configuration for the RAM upgrade ?

For the memory upgrade on the Turbo R GT, you "only" have to move R352 to the R353 place to make A15 to become "H" and A14 to become "L" (where H is High and L is Low in logical electronic), see table above for more information, those resistors are under the S1990 (solder side).

Fill the J302 near the R800 (components side) this jumpper is the MA19 address bit normaly it is not connected between S1990 and R800. Replace the 4 DRAM chips 44256 by new one: 514400 (90ns maximum) if you can find one, because even in Japan there is no more of them.

I know it because a friend of mine study Japanese in Japan!

But you can use a 1Mb SIMM (30 pin) for PC or ATARI & MAC, but you will have to make a PCB if you want. I have draw one using EAGLE layout editor.

Well, now you can close you MSX TurboR GT and switch it on to see: MAIN RAM 1024Kb!

But those 1024Kb only seems to work under DOS 2! under Basic or if a program use Memman, it doesn't work!

I have used an utility mapper tester from Digital KC (I get it when I bought my external 2Mb mapper), so when I run this utility it says that found 6-bit for the mapper (00PPPPPP where P is the page number on 6-bit! so 64 pages, but only 5 of them are available!

So only 512Kb can be used and not 1024Kb! and when I use ALLOCATE USER SEGMENT function of the MSXDOS2, it seems to work!

Source:
http://www.mail-archive.com/msx@stack.nl/msg07024.html

So looks like 1MB upgrade isn't that worth.

By Jipe

Paragon (1594)

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16-02-2010, 12:01

for the story

i know well this text made by Slayerman of F.U.C french united coders
we are making a little board for simm memory and decode bit 6 with F U C printed on
Slayerman have expand a GT on Tilburg Fair but don't work and i repair it at home ( just remove solder stain )
i don't know the owner of this GT because my english very very bad and i just reply " no problem for me ! "

the information for S1990 and R800 are on the japanase translate text

the schematic of the board for bit 6 is not making by me or Slayerman
i found it on a GT buy by a friend in Deutcland
just making the board and adapt schematic for ST and GT

pictures of this expand are on hnostar and made by Mirisoft but it's my work

rest a unknow MSX man in Deutchland who make extand the first time !!

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