DigiTech STUDIOVOCALISTEX Manual page 66

MIDI EDIT BUFFER EDIT
format:
procedure number 5Ch
PACKED {
edit buffer data
}
Example:
F0 00 00 10 00 37 5C ... packed edit buffer data ... F7 ; edit
buffer edit
MIDI KEY PRESS
format:
procedure number 5Fh
switch type
(4=switch, 5=control abs, 6=control inc, 7=control dec)
switch number
value (7th bit)
value (6-0 bits)
Example:
F0 00 00 10 00 37 5F 06 04 00 01 F7
F0 00 00 10 00 37 5F 04 14 00 01 F7
F0 00 00 10 00 37 5F 05 03 00 00 F7
PACKED BYTES OPERATION:
MIDI data is transmitted in a packed data format. The pack-
ing format groups the 8-byte data into 7 bytes. The most sig-
nificant bits of the next 7 data bytes are sent first then the 7
bytes with the most significant bit removed are sent. On
receiving the data, the data can be retrieved by combining
the most significant bit with the corresponding lower bits.
MIDI sysex data format reserves the most significant bit to
indicate status bytes.
Sending data via MIDI sysex must clear the most significant
bit, but this changes the data value, so the data must be
packed so information is not lost.
byte 1 : MSB byte
data 1 bit 7 in msb.0
data 2 bit 7 in msb.1
data 3 bit 7 in msb.2
data 4 bit 7 in msb.3
data 5 bit 7 in msb.4
data 6 bit 7 in msb.5
data 7 bit 7 in msb.6
byte 2 : data 1 byte (6-0 bits)
byte 3 : data 2 byte (6-0 bits)
byte 4 : data 3 byte (6-0 bits)
byte 5 : data 4 byte (6-0 bits)
byte 6 : data 5 byte (6-0 bits)
byte 7 : data 6 byte (6-0 bits)
byte 8 : data 7 byte (6-0 bits)
Example:
To represent the value 131, convert to hexadecimal (hex)
131 decimal = 0083 hex
Group the hex value into two pairs: 00 83
; rotenc inc 1
; edit on
; soft key 0
*
Translate each number into binary
0,0 hex = 0000,0000 binary 8,3 hex = 1000,0011 binary
result: 0000,0000 1000,0011
Remove the most significant bits (MSB) - the leading
numerals - and make them zeros
result: 0000,0000 0000,0011
Convert back to hex - result: 00, 03
Take the MSBs that were removed, (0 and 1 in this exam-
ple) and put them into binary byte:
result: 0000,0001 Convert to hex - result: 01
Add this byte before the other two
Final result: 131 decimal = 01,00,03 packed
Example 2:
To represent the value -50, convert to hexadecimal (hex)
-50 decimal = FFCE hex
Group the hex value into two pairs: ff ce
Translate each number into binary
F,F hex = 1111,1111 binary C,E hex = 1100,1110 binary
binary result: 1111,1111 1100,1110
Remove the most significant bits (MSB) - the leading
numerals - and make them zeros
result: 0111,1111 0100,1110
Convert back to hex - result: 7F, 4E
Take the MSBs that were removed, (1 and 1 in this exam-
ple) and put them into binary byte:
result: 0000,0011 Convert to hex - result: 03
Add this byte before the other two
Final result: -50 decimal = 03,7F,4E packed
* Note:The Calculator applet included with Microsoft
Windows has Hex conversion functions.
removed 0 & 1
removed 1 & 1
Decimal /