Alpha VS 100 - Pitch Control

8.
Pitch
control
•
This paragraph
is a
bit
technical,
but it
should be
understandable
.
The
computer
communicates
with
the
VS-100
via
an
eight
bit
byte.
The
VS-100
Votrax chip
uses
the lower
six
bits
to
select
one
of
the
sixty
four
phonemes.
The remaining
two
bits are
used to
select a
base
pitch. Two
bits
give
us
four
possibilities,
so
there are
four
base
pitches.
The
four
pitches
are
numbered
1 to 4.
Phonemes
with the
lowest
pitch
use
numbers
to
83.
Phonemes
with
pitch
2
use the
numbers
64
to
127, phonemes
with
pitch 3 use
numbers 128
to
191,
and
phonemes
with
pitch
4
use
numbers
192
to 255.
Note
that
phoneme
codes
0,64,128
and
192 are the
same sound,
only
at
different
pitches.
To
select
pitch
2,3 or
4,
add
64,
128 or
192 to
the
phoneme
code
in the
table.
—If you
are
using
VSEDIT,
keep
in mind the
following:
If
you
save
messages
with
pitch
2
(the default),
you
will
get ASCII
codes
64-127
embedded
in the
message
line.
These
codes
are
a mixture
of
upper
and
lower case
and some
other
characters.
They
will
not
affect
your
listing
in
any way.
If you
use
pitches
3
or
4,
you
will
see that
your
line
is
filled with
keywords
(i.<*.
F0RPRINTCHR£(
INKEYS
>
because
codes
above
127
are
"tokens"
for
BASIC
keywords.
The
line
will run
correctly,
however
it
will
look odd
in
listings.
(There
might
be
a problem
if
the
line
gets
longer
than
255
characters
on the
screen
. Everything
will
work
fine unless
you
try
to EDIT
the line
or if
you
try
to
save
it
in a
ASCII
file) .
—If
you
use
pitch
1,
the
program
line
will
contain
ASCII
control
characters,
such
as
"clear
screen"
and
"form
feed".
This
line
will
execute
properly,
but
it
will
produce
strange
effects
on
the
screen,
during listings.
This
is
because
the
control
characters
are
executed
when
that
line
is
listed.
Again,
this
has
no effect
on the
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