[comp.sys.atari.st] Shifter II chip/ STE and TT

cs161fca@sdcc10.ucsd.edu ( ) (11/25/89)

In some back issue of ST Report it wasn mentioned that the TT and
the STE use the same graphic chip.  It was suggested that it is
possible to get TT graphic modes out of STE.  All needed is some
routines to add the support of the extra graphic modes to the STE.
Is that true?

kbad@atari.UUCP (Ken Badertscher) (11/28/89)

cs161fca@sdcc10.ucsd.edu ( ) writes:

| In some back issue of ST Report it was mentioned that the TT and
| the STE use the same graphic chip.

That is wrong.  The TT shifter is different from the STE shifter. The
TT shifter gives you the new TT resolutions (640x480 16 color, 320x480
256 color, and 1280x960 monochrome), with the enhanced palette of 4096
colors in color resolutions.  The STE shifter has the enhanced palette,
but not the new resolutions.  The STE shiftger also allows fine screen
scrolling by allowing arbitrary (wordwise) screen alignment. The TT
shifter requires 8 byte alignment of screens. The two shifters are
compatible in that they are located at the same place in memory.
That's what gives us ST video compatibility on the TT.  But it is not
possible to use the STE shifter to get TT video modes.
-- 
   |||   Ken Badertscher  (ames!atari!kbad)
   |||   Atari R&D System Software Engine
  / | \  #include <disclaimer>