Part 3: Roland Nibble Formats
The image shows how we recognize the nibble formats in a Roland MIDI Implementation chart - 0000 in left hand nibble, xxxx in right hand.
- Address 00 01, Type, is Roland two nibble
- Address 00 07, Parameter 1, is Roland four nibble
- We also occasionally see Roland three nibble - the TRs use this for tempo
- Roland one nibble is a don't care - this is just a 0-15 control
- For an additional twist, the Parameter values shown below may start with an 8_, such as 8x 0x 0x 0x.
(Looking at right column, we see it covers a - to + range, doing the math, 0 is at 80 00 00 00. Negative values rarely appear, so we ignore the leading 8 in math, just add at end.) I have not seen the 8x format in the TRs, but I haven't been into effects yet, which is where it often appears.
Converting from the MIDI (Rn) to V
- Multiply MSB by 16, add next digit, repeat until LSB is added
- Four digit version (((((V3 * 16) + V2) * 16) + V1) * 16) + V0
Converting from V to Rn
- to load MD Named ticks (two digit): Rn = int(V/16) * 128 + mod(V,16)
- three and more get complicated, have to deal with remainders. Gotta remember where I have it captured. (Got too many Roland spreadsheets.)
Images
Roland Nibbles shown in MIDI Implementation Chart