User Guide
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7-Bit Data Packing
The general data packing scheme for Preset and Drumbeat Data Dumps groups 7 bytes of data, stripping off the MS bit of each, and
packing these MS bits into an additional byte. 7 bytes of internal memory yields 8 bytes of MIDI data.
Assuming 7 bytes of memory data are:
0:
AAAAaaaa
Memory byte 0
1:
BBBBbbbb
Memory byte 1
2:
CCCCcccc Memory byte 2
3:
DDDDdddd Memory byte 3
4:
EEEEeeee
Memory byte 4
5:
FFFFffff
Memory byte 5
6:
GGGGgggg Memory byte 6
Then it is sent over MIDI with the MS bits first as follows:
0:
0GFEDCBA Packed MS bits
1:
0AAAaaaa
MIDI Data Bytes
2:
0BBBbbbb
3:
0CCCcccc
4:
0DDDdddd
5:
0EEEeeee
6:
0FFFffff
7:
0GGGgggg
Note that fewer than 7 bytes can be sent, and the unused MS bits will be set to zero. For example, if two bytes are sent:
Assuming 2 bytes of memory data are:
0:
AAAAaaaa
Memory byte 0
1:
BBBBbbbb
Memory byte 1
Then it is sent over MIDI as a three-byte sequence, with the MS bits first as follows:
0:
000000BA
Packed MS bits
1:
0AAAaaaa
MIDI Data Bytes
2:
0BBBbbbb
