Atari 400 Technical Reference Manual page 156

SCREEN GRAPHICS
Hardware Capabilities
The hardware capabilities for screen presentations are ~uite
versatile; the
as
uses a very small amount of the capabilitv
provided. The means of extension, however, are non-trivial; and
making changes to a screen format while still utilizing the
resident Display Handler will be difficult. See the ATARI Home
Computer Hardware Manual for information regarding screen
presentations.
as
Capabilities
The resident Display Handler arbitrarily supports 8 of the 11
possible full screen modes (11 of 14 modes if the GTIA chip is used
in place of the CTIA). The resident Display Handler allows for an
optional "split-screen" text window of fixed size. The hardware
allows for many more options than the Display Handler supportsl as
will be seen by reading the ATARI Home Computer Hardware
Manual.
Cursor Control
You can control the Display Handler text and graphics cursors
directly (see Section 5 and Appendix L, 81-4).
Color Control
You can alter the color register assignments that the Display
Handler makes upon all OPEN commands (see Appendix L B7-8 and
elsewhere). Note that every system reset or Display Handler OPEN
will reset the values back to the system default.
OPERATING SYSTEM C016555 -- Section 11
171