Atari 800 User Manual

CHAPTER 4.
ADVANCED ATARI BASIC
Introduction
In this chapter,
we will expand on the concepts of BASIC
programming that were introduced in Chapter 3. The following
topics will be covered.
Atari ASCII
String
Handling
Variable Storage
PEEK
POKE
Screen Output Programming
Input Programming
Prompt Messages
INPUT Response Checks
CHR$
ASC
TAB
The Atari can
not store characters; it can only store numbers .
Before characters can be stored,
they must be converted to
numbers. Computers use special numeric codes to store
characters.
Mo st microcomputers use a code known as ASCII
(American Standard
Code for Information Interchange).
The Atari uses a special version of ASCII known as Atari ASCII.
When we refer to ASCII in this book, we will be referring to Atari
ASCII. The Atari ASCII
code set is outlined in Appendix C.

Atari 800 Specifications

General

Processor	MOS Technology 6502
Processor Speed	1.79 MHz
ROM	10 KB
Graphics	ANTIC and GTIA chips
Release Year	1979
Display Resolution	up to 320 x 192
Colors	128 colors
Sound	4 channels
Storage	Cartridge, cassette, floppy disk
Ports	Cartridge, serial, monitor
Operating System	Atari OS