Atari 400 User Manual

Atari BAS IC Reference Guide 101
If the sa me program was executed in the alt ernate character set,
by executing POKE 756, 226 after the GRAPHICS statement, the
word ATARI would appear in l ower case letters. A lso, in the
alt ernate character set, a "heart" ch aracter will appear in every
blank space. This occurs because the standard character set puts
a space
(COLOR 32) in areas where no character h as been
ass i gned. When the conv ersion to the a lt ernate character set
occu r s, COLOR 32 is int erpreted as a "heart" in co lo r register 0
(Table
9-4). As a r es ult , an o range "heart" will appear in every
space except whe re the word ATARI appears.
In grap hics modes 3 through 7, the CO LOR statement is u se d to
choose the co l or register that will be used to plot points and
draw lin es .
Graphics modes 3 through 7 are different from modes 0 through
2 because modes 0, 1 and 2 are used to place characters on the
screen. Graphics modes 3 through 7 are us ed to place picture
el eme nt s (pixels) on the sc reen. A pixel is a rectangle that is
r efe rred to by its coord inates (co lumn and row) on the display. In
modes 3 through 7, the COLOR statement actually chooses a
col or register, not a character.
EXAMPLE
10 GRAPHI CS 3
20 FOR T = 0 TO 3
30 CO LOR T
40 PLOT T,O
50 NEXT T
The
previous examp le displays the 4 co lors of graphics mode 3.
Line 40 plots a pixel at column T, row O. The color of the pixel is
determined by the last COLOR statement. The first time through
the program, T is set equa l to 0 at lin e 20. Line 30 indicates that
col or T is used. Since no SETCOLOR stateme nt was executed, the
defa ult co lors are used.

Atari 400 Specifications

General

Manufacturer	Atari
Model	400
Type	Home Computer
Release Year	1979
CPU	MOS Technology 6502
CPU Speed	1.79 MHz
ROM	10 KB
Operating System	Atari OS
Keyboard	Membrane keyboard
RAM	8 KB (expandable to 48 KB)
Graphics	ANTIC and GTIA chips
Sound	4 channels
Display	RF output for connection to TV
Storage	Optional cassette tape drive or floppy disk drive
Ports	Cartridge
Display Resolution	320x192 (16 colors)