Atari XL User Manual

152 The Atari XL Handbook
21000 RETURN
22000 DATA 1,1,1,-1,1,0,0,0,-1,1,-1,
-1,-1,0,0,0,0,1,0,-1,0,0
To use this program you will need a joystick, which
may be plugged in to ei ther of the ports. The
program is controlled entirely by the joystick, with
no keyboard actions at all.
After the setting up routines have been run,
pressing the Fire button on the joystick will display
a blank graphics 7 screen, with a text window. The
cursor will be visible as a yellow spot in the top left
corner of the screen. Use the joystick to move the
cursor around the screen, and hold down the Fire
button while moving the cursor to draw lines.
To change colour or clear the screen, move the
cursor down into the text window, position it over
the command you require, and press Fire. There
are four colours to choose from: red, yellow and
blue, and the background colour (selected by
ERASE).
If you find that the display is too fine in mode 7, you
can change the program to run in mode 5 by
altering line 1000, when specifies the mode, and
also by altering the tests in lines 1140 and 1150
which check whether the cursor is running off the
edge of the display. You will also need to alter line
2020, which calculates the cursor position in the
text window after it crosses from the graphics
display, and line 2300, which calculates the cursor
position in the graphics display as the cursor leaves
the text window.

Atari XL Specifications

General

Release Year	1983
CPU	MOS Technology 6502C
Graphics	ANTIC, GTIA
Sound	POKEY (4 channels)
Storage	Cassette tape
Ports	Cartridge
Operating System	Atari BASIC
CPU Speed	1.79 MHz
RAM	64 KB