Model 8-432
ver. 2.0
MIDI SYSTEM EXCLUSIVE COMMUNICATION
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© 2012 CHD Elektroservis
JP4-KBD
MIDI Interface for Jupiter 4 Keyboard
Model 8-432 ver. 2.0
SYSTEM EXCLUSIVE COMMUNICATION
JP4-KBD interface disposes of system of System Exclusive communication which enables to
receive a SysEx Messages for changes of all parameters.
Software generator for simple creation of SysEx messages for control of JP4-KBD is available on
supplemental CD-ROM. The generator is based on Java scripts. Any message for the interface setting
described below can be created with help of this generator.
SYSEX MESSAGES STRUCTURE
JP4-KBD receives own specific messages for changes of parameters setting etc. with this
structure:
F0h
00h 20h 21h
ii
56h
aa
dd
xx
F7h
Start SysEx
Manufacturer ID
Device ID
Model ID
Address
Data
Checksum
End SysEx
DEVICE ID BYTE
Device ID byte identifies MIDI device exactly. It is very significant if more than one JP4-KBD
interface is used in MIDI system simultaneously.
Device ID is equal to number of just active MIDI channel (00h for channel Nr. 1, 01h for channel
Nr. 2 etc.). Any of values from 00h to 0Fh is accepted if OMNI mode is active. Next possible value of
Device ID is 7Fh - it is universal Device ID which the interface recognizes whenever independently on
just active MIDI channel number or OMNI mode.
For all others values of Device ID (from 10h to 7Eh), the message is evaluated as invalid and it is
ignored by the interface.
ADDRESS BYTE
Address byte specifies parameter to be changed. Allowed address range is from 00h to 04h:
aa = 00h Æ
aa = 01h Æ
aa = 02h Æ
aa = 03h Æ
aa = 04h Æ
aa = 05h Æ
MIDI Channel – Receiving MIDI channel
Key Shift – Keyboard transpose
Key Priority – Key priority parameter
Pitch Wheel Range – Pitch bend range
Arpeggio Clock Rate – Arpeggiator clock source selection
All – change of values of all parameters in internal memory of the interface
For addresses aa = 00h to 04h, value of only one parameter is changed temporarily – new value
is valid until next change is done or the instrument is turned off. For address aa = 05h, values of all
parameters are changed permanently - new values are stored in internal memory. If the address is out
of range 00h to 05h, the message is evaluated as invalid and it is ignored by the interface.
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Copyright © 2012 CHD Elektroservis. Všechna práva vyhrazena.
Tato publikace ani žádná její část nesmí být reprodukována v jakékoliv formě bez písemného souhlasu výrobce zařízení.
JP4-KBD
MIDI Interface for Jupiter 4 Keyboard
Model 8-432 ver. 2.0
DATA BYTE
Data byte specifies new value for parameter selected by aa address. Its value depends on
required value of the parameter.
• DATA FOR MIDI CHANNEL
If aa Address is 00h, dd Data byte specifies new number of receiving MIDI channel. Valid value
of dd byte is from 00h to 10h.
Values from 00h to 0Fh represent the MIDI channel numbers from 1 to 16. If the value is 10h,
OMNI mode will be active. For values from 11h to 7Fh, the message is evaluated as invalid and it is
ignored by the interface.
• DATA FOR KEY SHIFT
If aa Address is 01h, dd Data byte specifies keyboard transpose – it means relation between
MIDI Note number and assigned key. Valid value of dd byte is from 00h to 4Fh (+0 to +79 semitones).
The value specifies number of MIDI note which will be assigned to first key from left (i.e. to
lowest C) of the instrument’s keyboard For values from 50h to 7Fh, the message is evaluated as
invalid and it is ignored by the interface.
• DATA FOR KEY PRIORITY
If aa Address is 02h, dd Data byte specifies selected key priority mode. Valid value of dd byte is
from 00h to 03h.
“Last Key“ priority is selected for value equal to 00h, “Higher Key“ priority is selected for value
equal to 01h, “Lower Key“ priority is selected for value equal to 02h and “None“ priority is selected for
value equal to 03h. For values from 04h to 7Fh, the message is evaluated as invalid and it is ignored
by the interface.
• DATA FOR PITCH WHEEL RANGE
If aa Address is 03h, dd Data byte adjusts maximal range of MIDI Pitch Wheel (Pitch Bend)
controller. Valid value of dd byte is from 00h to 18h.
For value 00h, Pitch Wheel controller will be inactive – its movement will have no effect. Values
from 01h to 18Fh represent allowed range of Pitch Wheel controller in semitones (from ±1 to ±24
semitones). For values from 19h to 7Fh, the message is evaluated as invalid and it is ignored by the
interface.
• DATA FOR ARPEGGIO CLOCK RATE
If aa Address is 04h, dd Data byte selects source of clock for instrument’s arpeggiator. Valid
value of dd byte is from 00h to 7Fh.
If the value is 00h, internal instrument’s arpeggio clock generator is selected. For values from
01h to 7Fh, arpeggiator tempo is derived from MIDI clock. Arpeggiator’s period length is in reciprocal
proportion to the data byte value in this case – for the value equal to 7Fh, arpeggiator’s period is one
MIDI clock pulse, for the value equal to 7Eh, arpeggiator’s period is two MIDI clock pulses and so on.
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Copyright © 2012 CHD Elektroservis. Všechna práva vyhrazena.
Tato publikace ani žádná její část nesmí být reprodukována v jakékoliv formě bez písemného souhlasu výrobce zařízení.
JP4-KBD
MIDI Interface for Jupiter 4 Keyboard
Model 8-432 ver. 2.0
CHECKSUM BYTE
Checksum byte confirms validity of System Exclusive message. It must be calculated so that
seven-bit sum of bytes from “Model ID” to “Checksum” is equal to zero.
If Checksum byte is invalid, whole message is invalid too and it is ignored by the interface.
Example of checksum calculating
Task:
Set the receiving MIDI channel to Nr. 1
Solution:
• We don’t know what number of MIDI channel is just active so universal Device ID (7Fh) will be used,
• address byte (parameter number) will be 00h,
• requested MIDI channel number is 1 so data byte will be 00h:
Start SysEx :
Mfr ID :
Device ID :
Model ID :
Address :
Data :
Checksum :
End SysEx :
F0h
00h 20h 21h
7Fh
56h
00h
00h
xx
F7h
Now the checksum byte has to be calculated as 7-bit complement of sum from Model ID to Data bytes:
00h – (56h + 00h + 00h) = 2Ah
Form of whole required System Exclusive message is after checksum refilling:
F0h 00h 20h 21h 7Fh 56h 00h 00h 2Ah F7h
Immediately after that message is received, the interface starts to accept MIDI channel
messages on MIDI channel Nr. 1.
Manufacturer :
CHD Elektroservis
Nad kundratkou 27, 19000 Praha 9
Czech Republic
[email protected]
www.chd-el.cz
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Copyright © 2012 CHD Elektroservis. Všechna práva vyhrazena.
Tato publikace ani žádná její část nesmí být reprodukována v jakékoliv formě bez písemného souhlasu výrobce zařízení.