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:
Byte Function
FOH
Begin System Exclusive
41H RolandIRodgers SysEx
ill
10H Device
ill*
30H Model
ill
(30 = organ)
12H Data Set Command
*Note: This byte is usually 10H; however, the organ receives
OOH
-
OFH
and can be set to trans-
mit Device
ill
OOH
or
transmit and receive any Device
ill
between 10H and IFH. See the lastpage
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 702:
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 assign-
ment
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: 01H
Offset byte:
Data bytes:
OOH
- 22H This byte indicates the offset
of
the
fITst
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.
dd, dd,
...
The data bytes represent the new state
of
the bit map beginning
at the offset specified above. Any number
of
data bytes up to
37
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