Rodgers Instrument Corporation
MIDI System Exclusive Code
Rodgers organs use a subset
of
the Roland standard MIDI System Exclusive format. All Rodgers SysEx
packets use the Roland "Data Set" command, listed under "One Way Transfer Procedure" in the Roland
System Exclusive format specification. The first five bytes
of
this type
of
packet are as follows:
FOH
41H
lOH
30H
12H
Function
Begin System Exclusive
Roland/Rodgers
SysEx ID
Device
ID*
Model ID (30 = organ)
Data
Set Command
*Note: This byte is usually
lOH;
however, the organ receives
OOH
-
OFH
and can be set to transmit
Device ID
OOH
or
transmit and receive any Device ID between lOH and lFH. See the last page
of
these notes
for more information.
This header is then followed by the message body. The message body contains a subcommand byte, an
optional offset byte and a variable number
of
data bytes followed by a checksum byte and a MIDI
End
Exclusive byte (F7). The checksum byte value is such that
if
all bytes beginning with the subcommand byte
and ending with the checksum byte are added, the lower 7 bits
of
the result will be all zeroes.
The following messages are used by Rodgers as
of
the introduction
of
model 595:
1.
Stop Change
This message is transmitted each time one
or
more stops, couplers,
or
auxiliary controls changes state.
The state
of
each control
is
represented as a bit
in
one
of
the message data bytes. The assignment
of
controls
to specific bits is standardized for all Rodgers organs by use
of
the master code assignment list included
herein. Activated controls
("on") are represented by ones in the bit map. This message is transmitted
on
the
Sequencer and Pipe ports only on organs which have a separate MIDI Instrument port.
It
can, however,
be
received on the Instrument port
as
well.
Subcommand byte: OlH
Offset byte:
OOH-
22H
Data bytes:
dd,dd,
...
36
This byte indicates the offset
of
the first data byte from the beginning
of
the bit map. Normally, this will be zero, and the entire map (35
bytes) will be transmitted.
It
is possible, though, to send only part
of
the map beginning with the byte indicated by this value.
The data bytes represent the new state
of
the bit map beginning at the
offset specified above. Any number
of
data bytes
up
to the
full
length
of
the bit map may be sent, although the entire map is usually
transmitted. Refer to the included chart for stop map assignments.
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