Atari 400 User Manual

158 User's Handbook to the Atari 400/ 800 Computers
EXAMPLE
POINT #3 , SECT, BYTE
In the preceding example, the file pointer for the disk file
opened through channel #3 is moved to the sector specified by
the variable, SECT, and byte within that sector specified by the
variable, BYTE.
POKE (pOK.)
The POKE statement is used to store one byte of information in a
particular memory location.
CONFIGURATION
POKE a, b
The first argument of a POKE statement is the memory location.
If a POKE statement specifies a memory location that does not
exist, the POKE statement has no effect. Also, if a POKE
statement specifies a memory location that is part of the ROM ,
the POKE statement has no effect.
The second argument
of a POKE statement is the value that is to
be stored at the specified memory location. The value of the
second
argument represents one byte. As a result, the value must
be an integer between 0 and 255.
If either of the arguments of a POKE statement is not an integer,
it is rounded off. A value error occurs if the memory location
specified is greater than 65535 or the value of the second
argument exceeds
255. A value error also results if either of these
arguments are negative.
If the POKE statement is not used carefully, it can seriously
disrupt the operation of the computer.
Appendix E contains information regarding commonly used
memory locations.

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)