Structure Of System Exclusive Messages - Roland TR-808 User Manual

TR- - - - 808 MIDI Interface TR 808 MIDI Interface
TR TR 808 MIDI Interface 808 MIDI Interface
3.3. System Exclusive Messages

3.3.1. Structure of System Exclusive Messages

If necessary, TR-808 MIDI interface can be reprogrammed by user with help of SysEx messages.
Transmitting of "Bulk Dump Load" SysEx message from host system to internal memory of the
interface can change system parameters (channel for MIDI communication setting and mode of LED
indicator setting) or it can change the table of tone generators assigning and their dynamic range
setting for requested MIDI note (drum map definition).
"Bulk Dump Load" message format is always:
F0h
00h 20h 21h
7Fh
61h
20h
aa
dd dd dd
xx
F7h
Address aa selects group of parameters for changes. Valid range is 0 to 79 (00h to 4Fh).
Datablock dd dd dd always includes three databytes. Their values determine values of parameters
given by address aa. Checksum xx is created in standard way - seven-bit sum of bytes from "Model
ID" up to "Checksum" included has to equal to zero.
If address aa is 0 to 78 (00h to 4Eh), parameters for assignig of tone generator and its dynamic
range to some of MIDI notes are selected. Address 0 (00h) selects note No. 12, address No. 1 (01h)
selects note No. 13 etc. up to addres 78 (4Eh) which selects note No. 90.
• First databyte in block is then number of assigned tone generator. Valid range is 0 to 11 (00h to
0Bh). If zero is selected, none generator is assigned to selected MIDI note. Values 1 to 11 defines
tone generator as described in table 3.
• Second databyte in block sets minimal output level of tone generator (for "Velocity" = 1). Its value
can be in range from 0 to 127, but the value must not be greater than value of third databyte.
• Third databyte in block sets maximal output level of tone generator (for "Velocity" = 127). Its value
can be in range from 0 to 127, but the value must not be lower than value of second databyte.
Group of system parameters is selected for address aa equal to 79 (4Fh).
• First databyte in block then sets the number of MIDI channel selected for data receiving. Valid range
is from 0 to 15 (from 00h to 0Fh) for MIDI channel from 1 to 16 selection.
• Second databyte in block disables (value equal to 0) or enables (value equal to 1) the indicaton of
received MIDI commands by LED embedded in START / STOP button.
• Third databyte is not used, it must be always equal to 0 (00h).
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Start SysEx
Mfr ID
Device ID
Model ID
Command (Bulk Dump Load)
Address
Datablock
Checksum
End SysEx
8
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