Atari Forum TT FAQ

Here are some answers to question asked by the forum users. The answers links back to the postings on the Atari Forum.

Graphic system

Where to get drivers / how to use Crazy dots graphics card ?

https://www.atari-forum.com/viewtopic.php?f=27&t=16371
The latest driver for Crazy dots will be from NVDI 5.02. Download a nvdivga.inf (for nvdi driver) for your monitor here.

How to get ET4000 Crazy Dots working with NVDI?

https://www.atari-forum.com/viewtopic.php?f=27&t=16693 https://www.atari-forum.com/viewtopic.php?f=27&t=16636

Your autofolder should have the following programs in the following order:
1. INIT.TOS, REDIRECT.PRG, NVDI.PRG, SLCT_DEV.PRG.
2. Redirect simply changes output to your SVGA monitor. NVDI starts the drivers and Slct_dev enables you to switch to another resolution at the end of boot
Create your own VMG-4000 file. For 1024x768 @ 60Hz (perfect for LCD monitor), try the following:

VESA XGA Timing are:
Horiz Front porch 24
Horiz Sync pulse 136
Horiz Back porch 160
Vert Front porch 3
Vert Sync pulse 6
Vert Back porch 29

To convert to VMG timings:
Schwarzsch = Total length of black area (Front Porch+Sync Pulse+Back Porch)
Impulsstart = Start point of sync pulse (pixels or lines + Front Porch)
Impulslange = Sync pulse length (Sync Pulse)

so in this case the numbers for VMG would be (with the pixel clock set to 65Mhz):
Horiz Schwarzsch = 320
Horiz Impulsstart = 1048
Horiz Impulslange = 136
Vert Schwarzsch = 38
Vert Impulsstart = 771
Vert Impulslange = 6

Attention to sync polarity should also be noted, though i just select these to get the best picture, rarther than following the spec.

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Compatibility

Which game is compatible to the TT ?

https://www.atari-forum.com/viewtopic.php?f=26&t=20735&p=183605
The first post in the above thread contains a list of TT compatible games.

How compatible is the TT?

https://www.atari-forum.com/viewtopic.php?f=27&t=10013

Compaitibility-wise its somewhere between a MegaSTE and a Falcon. Its got everything the ST has got plus the STE's hardware scrolling and DMA sound but no blitter chip.
Gem programs will work most probably, games won't usually. 'Empire - Wargame of the century' and 'Monkey Island' are exceptions. Monkey will run in TT medium btw without probs.
There's a whole bunch of smaller games that are working with the TT.
A trick to get those programs working, may be just needing the load-bits set, and some experimenting.

How to increase compatibility of ST programs in TT?

https://www.atari-forum.com/viewtopic.php?f=27&t=13401
Three common problems for ST programs not working on the TT are:

CPU caches: just try to turn them off in the desktop
32-bit bus: up to the Falcon, it was no problem to have something other than $00 in the high byte of an address or address register. On the TT, this will give a bus error when this address is accessed. This is usually caused by sloppy coding. Would have to be fixed per program.
external/internal video snyc: lots of games/demos write to $820a.w. On the TT, bit 0 is just the other way round as it is on other machines: it has to be 1 to get a picture on screen.

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