NOV.1st,1982
CPU
PROGRAM
The
CPU
80C49-6-7301 controls
the various
modes and
functions of
the SH-101
through a series of
programmed
steps, as
shown in the
attached flowchart. These
actions
are described
below.
Note:
Steps
3 through
1 3 are
a series of program
steps
that
are
sequentially
executed
by the CPU
at
1.5
to
3.5msec
intervals. The
CPU can modify this
se-
quence any
time new
data is input.
1.
TEST MODE
The Test mode allows
easy
adjustment of the SH-101.
To enter the Test mode, first turn the power switch Off.
This is necessary as the Test mode cannot
be
entered
while the SH-101 is in any of the normal operating
modes. Now simultaneously press both the LOAD and
KEY TRANSPOSE buttons
and
turn the power switch
On. The CPU sets the voltage
at
the KCV and at the
Range
to zero and turns the Gate Off. The unit is
now
in the Test Mode. The voltage values at the KCV
and the Range, and the status of the Gate change ih each
of the
function modes listed below.
Function
Button KCV Range Gate
PLAY 2.75V OV Off
ARPEGGIO DOWN 2.5V OV Off
ARPEGGIO U&D 4.75V OV On
ARPEGGIO UP
OV 4.75V On
LOAD
OV
OV Off
To
enter a normal mode, either press the Hold button
down, or turn the power switch Off and then back On
again.
2. INITIAL SET
The CPU performs Initial
Set when the
power switch is
turned On or when
the HOLD button is
pressed during
the Test mode. This operation deletes all the
data
that is
stored in the built-in RAM, such
as
Keyboard and switch
mode
data, but does not delete the Sequencer data.
3. RANGE DATA
READ
The
CPU reads and memorizes the positions of the VCO
Range, TRANSPOSE
(L, M and H) and GATE/TRIG
{LEO
)
switches.
4.
RANGE DATA OUTPUT
The CPU sends
the VCO Range data (read in Step
3)
to
the
D/A Converter where it is converted into analog-
equivalent values.
RangeSelector Range Data
16'
8
'
4'
T
IV
2V
3V
4V
If the CPU contains Key Transpose data (stored during
step 8 of the previous program execution), the Key Shift
data is
added to
the Range Selector
data.
For example,
if the user selects the lowest F-key and
sets
the Range
Selector
to
16',
the Range
data
value will
be
0.417V.
Likewise, if the user selects
a
higher C-key
and sets
the
Range Selector to
2',
the Range data value will be 5V.
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