When this page was first designed there was only one other Atari TT page on the net. Since this pages inception there have been several new TT pages, most of which surpass the information on this page by some great deal. This page is sticking around however and they will gradually expand as I gather more information about Atari's 'fastest' computer. We need your help for this one so if you can add anything to this page, please get in touch. At the moment the info is as such...

Basic Specs

CPU: Motorola 68030 @ 32 Mhz (system bus @ 16 MHz) with FPU: Motorola MC68882
Note: The early TT systems ran a 68030 at 16mhz. Later a daughterboard was added to bring the processor speed to 32mhz.

RAM: 2 MB ST RAM expandable to 12 MB; plus up to 256 MB TT RAM on daughter board using either 30-pin or 72-pin SIMMs

Sound: Yamaha YM2149 + enhanced DMA sound (STe)

1.44 MB (later version) 3" floppy disk drive

Ports: MIDI In/Out, 3 x RS-232, Serial LAN RS-422, Printer, VGA Monitor (RGB and Mono), Extra Disk drive port, SCSI port, VMEbus inside case, detachable keyboard, Joystick and Mouse ports on keyboard

Operating System: TOS 3.01 - 3.06 with GEM

Display modes: 320200 (16 color), 640200 (4 colours), 640400 (mono), 640480 (16 colours), 320480 (256 colors), 1280960 mono TT high with special 19 in (483 mm) monitor, palette of 4096 colours

(Source: Wikipedia: http://en.wikipedia.org/wiki/Atari_TT)


Here are the schematics for the TT. These are courtesy of Jan Thomas and were originally on his web page..



Atari ST RAM 4mb Board

Jumpers: 6 pins relating to 2 sets of jumpers. These tell the TT how much ST RAM the board is carrying. There should be one jumper.

Position Result

1 and 2

2 and 3
1 and 2
2 and 3

A more complete break down of the ST Ram in the TT can be found at http://mcp.selfip.com/download/st-r_up1.htm . There are also details on a link on that page to upgrade the RAM to 8mb. Thanks to Lonny Pursell for forwarding this page to us.

Atari TT Fastram Expansion Board 4/16mb Fitting and Configuring

The TT 4/16mb Ram Board. Pictures courtesy of Grahame

Locate the correct internal expansion port on the front left hand side of the computer just in front of the power supply (computer facing as you would normally use it). Locate two screws on either side of this port and remove (retaining). Insert the RAM board into the expansion board. This should only go in one way, with the chip on the board on the right and the simm sockets on the left. Populate board with memory (4 x 1mb or 4 x 4mb 30 pin simms). Memory must be 70ns or 60ns in speed (or faster?). Parity or non parity makes no difference. Burst (Fastpage) mode can only accessed using special SIPP memory. Jumpers need to be set according to the table below. Note: The labels on the memory board are upside down in relation to the pin numbers. So if your looking at the board with the writing the correct way then instead of the pin numbers being 1 - 2 - 3 from left to right, they are 3 - 2 - 1.

Memory Board Jumper Settings

Setting   Jumper Number/Label and Position


Jumper position


Jumper Position


Jumper Position

Simm size 1mb x 4 (4mb) 2-3 2-3 2-3
  4mb x 4 (16mb) 1-2 1-2 1-2
Starting Ram Address $0100 0000 W103 W104  
  Jumper Position 2-3 2-3  
Address Mode   W105    
Non Burst Jumper Position 1-2    
Burst Jumper Position 2-3    

One thing to note if you have a Revision 'A' memory board is that a resistor needs to be added to the board as detailed below (This is an unlikely situation to occur).

If this is the case then: Add 820ohm 1/4W 5% Resistor (R102) from J101-40 to J101-49 on the component side (memory board). Use insulating sleeving on both legs of resistor.

Known working simms for Atari 4/16mb TT Ram expansion?


Other Known TT Ram Expansion Boards

aixTT - 64mb

No details as yet.

CC Meg

Graham has provided some pictures of this RAM board, but as such we have no other info about it other than that it was made by Catch Computers in 1993. If anyone knows anything about this board, particularly the jumper settings then please get in touch.

Top view

Bottom View

Close up, including jumpers

Magnum TT 256mb

No details as yet.

Mighty Mic

32mb and a successor to this with 64mb (possibly the aixTT?)

Here are two pictures of the Mighty Mic board:

Top View

Bottom View

Jumper Settings for Mighty Mic

Note: These jumper settings seem to be slightly unreliable in results, the one for 32mb is confirmed, though other results are variable...

Jumper Pin 1 Pin 2 Pin 3 Bank 0 Bank 1 Total
J1       0mb 4mb 4mb
J1       4mb 4mb 8mb
J1       16mb 0mb 16mb
J1       16mb 4mb 20mb
J1       16mb 16mb 32mb
J1       0mb 4mb 4mb

J1       0mb 16mb 16mb
Thanks to Grahame for providing all the information about the Mighty Mic.

More info on any of these memory expansions would be appreciated. Particularly memory board jumper information.

Motherboard Jumper Information

Three sets of jumpers are located adjacent to the TT ram expansion slot, adjacent to the TOS ROM chips. These seem to effect how the ROM is accessed, and adjusting them seems to do nothing other than stop the machine booting. Presumably they allow the machine to distinguish between different TOS versions or ROM chip sizes, though clarification on this issue would be helpful.

DIP Switches on TT motherboard

As far as I'm aware only switch 7 has any useful effect on the TT, allowing you to select whether either a high density or double density disk drive is in use. Switch 8 can be used to turn off the DMA sound hardware (though why you'd want to do this is beyond me!). Switch 5 is used by the CaTTermaran to activate it. Switches 1 - 4 and 6 have effects which are so far undocumented. If you have a clue what these do then please get in touch.

SCSI Drive

The TT can be fitted with a SCSI drive internally and can also be connected to a standard SCSI device externally by means of a full SCSI port at the rear of the machine. The internal SCSI port is a 50 pin connector (SCSI 2), whereas the external port is a 25 pin.

HS Modem Info

These programs are needed from the HSModem package to control the TT's plethora of serial ports. Install these in the auto folder, before STiK or STiNG. Drivin.prg must be the first to load, use Autosort or a similar program to reorder the way the programs work.



The TT can operate perfectly well with a standard VGA monitor. This will give you access to the ST video modes, TT Low Resolution and TT Medium Resolution. There is a slight problem with the TT's VGA output in that the image can on some monitors appear to be over one side of the screen, and TT High resolution can only be obtained by using a special 'ECL' monitor, manufactured by Atari themselves, due to an extremely high refresh rate apparently, and other incompatibilities with the VGA signal. The monitor has a special pin which when plugged into the TT monitor port activates the special high res mode (much like the SM124 on the ST)..

Here are some pictures (courtesy of Grahame, say thankyou boys and girls!) of the TT VGA/ECL monitor switch.



Cable and shielding.

Keyboard Faults

The keyboard in the TT, while being one of Atari's better efforts, is still somewhat cheaply made. Several things can go wrong. Damage to the cable running from the TT to the keyboard is fairly easy to fix as it is a standard phone cable. Keys which do not work on the keyboard are likely to relate to degradation of the plastic Mylar membrane into which the keys press. This is the cheapest part of the TT (design wise that is), A problem with this is likely to need a replacement mylar, which can be obtained from the usual US Atari suppliers. Finally the mouse and joystick ports can break in a similar fashion to those on the ST, with the connections between the ports and the keyboard circuit board breaking. These can either be re-soldered (a somewhat tricky job due to the way they are installed), or you can try the bodge fix (which I used on my TT). Remove the casing so you can see the port in question, then wedge a folded piece of card above the port which pushes the connectors back into contact. Done internally it's barely noticable and could breath new life into the keyboard.

Dumping TOS Rom images to Eproms

(Information provided by Linkovitch and Grahame- Thanks)

If you have an earlier version of TOS 3 or you have a foreign computer then you can burn TT Roms using an EPROM burner. The TT TOS needs to be split over four chips. It is important that the chips go in the right sockets on the motherboard. The sockets are labelled EE EO OE and OO (E for Even, O for Odd).

Looking at the motherboard from the front (as the machine would normally face you) the chips are inserted starting on the right hand side in a horse shoe shape, Bottom right, top right, top left, then bottom left. This (I think ) follows the sequence of the component number on the PCB artwork, but I cannot say 100%.

Grahame also says he could not get 27Cxxx uv roms to work with his TT, though he also mentioned that his German TT originally came with them.

TOS 3.06 UK ROM - This has been successfully used to create a working ROM. You will need to split and burn this image to four ROM chips. Thanks to Grahame we can now do this for you so here is the ROM split onto four chips, there are two versions, one for 2mb Flash ROMs and one for 1mb Flash ROMs.

1mb Flash ROMs 2mb Flash ROMs
Download Download

NVRAM/Clock Battery

The battery powering the TT's clock is located at the back of the computer or the right hand side. In a somewhat tacky fashion it seems usual for it to be secured to the casing with tape. For the older revision TT, with a metal shielding within the case the battery can be replaced by four 1.5 volt alkaline batteries. For newer TTs with brown colouring on the inside of the plastic case. The battery is a 3.6 volt affair. These appear to be still obtainable from their manufacturer Tadiran (Part no. TL 5242/W), however you can save expense by sourcing your own 3.6 volt supply. Grahame e-mailed to say he has tried a double aaa battery holder from Maplin, and is currently using a CR2032 battery holder removed from a PC motherboard and encased in heat shrink sleeving,using the original wiring of course observing correct polarity connections.

Graphics Cards

There are several sites (see links at bottom of this page) that describe the various graphics cards that can be added to the TT's VME bus. For a starter you could do a lot worse than having a look at Lonny Pursells' excellent and comprehensive summary of the VME graphics cards available for both the TT and Mega STe on his webpages.


TT System disk (MSA format)

TT Digger

HSModem TT

Teradesk Desktop (Jazz up that dull Atari offering!)

Patches - Fortunately TOS 3.6 is pretty stable, but here are a few patches that you might find useful.

Game Compatiblity

Generally a lot of the later ST games seem to work fine with the TT. Despite rumours to the contrary. Earlier games are a lot more hit and miss (Please let us know if you have a game that works so we can add it to this somewhat unfinished list ;-)). Thanks to Madmax1 for some additions to this list.

Chu Chu Rocket

Golden Axe

Hard Driving 2

Monkey Island

Operation Stealth

Sabre Team

Shadowlands/Shadow Worlds

Teenage Mutant Hero Turtles

Wolfenstein 3D


Atari TT Headquarter

This newer site is an excellent source of TT information.



http://www.zhell.co.uk or http://zhell.atari.org

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