Atari 400

Atari Graphics & Sound 285
5. Execute a POKE to address 765 . The argument specified
with POKE should be set equal to the COLOR statement
that
was used to plot the point s and lines. (Reference line
700 in XIO Example Program).
6. Execute XIO 18,#6,0,0, "S :" and the figure will be filled.
(Reference line 800 in the XIO Example Program).
Atari Sound
The Atari's built-in speaker is controlled via memory address
53279 . When a a is stored at that address, an oscillation is sent to
the speake r. By causing the speaker to oscillate a number of
times, the speaker will emit a sound. The following program will
result in the Atari's speaker emitting sounds.
READY
100 FOR I = 1 TO 100
200 POKE 53279 ,0
300 NEXT I
400 END
RUN
Generally, the television set's speaker is used to produce sound
rather than the Atari's
built-in speaker. In Atari BASIC, the
SOUND statement is used to output sound via the television set's
speaker.
The
SOUND statement is used with the following configuration.
SOUND voice, pitch, distortion, volume
Together these four arguments determine the sound produced .
voice sets one of four voices available with the Atari. These are
numbered from a to 3. These four voices are independent of
each other. In other words, as many as four voices can be
sounded at the same time .
pitch sets the pitch of the sound produced by the SOUND
statement. The pitch can range from a to 255 . The highest pitch
begins at a and the lowest at 255.