Korg SDD3000 Pedal

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  • #115262
    Anonymous
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      Hi to all,

      I tried as first attempt to do something for this pedal that has midi in/out. It has only few functions so is very simple.
      I have some problems with the dump data conversion table made by korg and the implementation of it on the sysex messages. There’s someone who’s already done something for this pedal or maybe that have experience with korg midi implementation and that can do something for it?

      Many thanks for the help

      I have attached its midi chart

      #115273
      Possemo
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        I know this is a pain in the a… – crunching 8-bit data into a 7-bit MIDI datastream is not an easy thing to do. There are 3 different methods I know of – from various manufacturers:

        1.) the easy one: just use parameters with max 128 values (7-bit = 2 exponent 7 = 128). This is not suitable for every parameter. It will provide a somewhat coarse parameter resolution on e.g. filter cutoff. The big advantage: no conversion needed, just send the values.

        2.) 4-bit nibbles: Break each 8-bit Byte into two 4-bit nibbles. This will double the datastream – not very efficient but ok for smaller dumps. It is relatively easy to build such dumps with Lua scripts within Ctrlr.

        3.) the 7-bit worm: I’ve seen this method when I looked at the Korg 05R/W sysex dumps. It is highly efficient as there will be no wasted bits like on the 4-bit nibble method but definitely a pain in the a.. to code and decode.

        This schematic explains it all:

        MIDI DATA ( 1set = 7bit x 8Byte )
             b7b7b7b7b7b7b7     b6    ~     b0     b6 ~~    b0     b6    ~     b0
           +-+-+-+-+-+-+-+-+  +-+-+-+-+-+-+-+-+  +-+-+-~~-+-+-+  +-+-+-+-+-+-+-+-+
           |0| | | | | | | |  |0| | | | | | | |  |0| |    | | |  |0| | | | | | | |
           +-+-+-+-+-+-+-+-+  +-+-+-+-+-+-+-+-+  +-+-+-~~-+-+-+  +-+-+-+-+-+-+-+-+
           7n+6,5,4,3,2,1,0         7n+0          7n+1 ~~ 7n+5         7n+6

        To send the first seven 8-bit bytes you do the following: send eight 7-bit bytes. The first byte contanis the high bits of the following seven bytes, then it starts again with the next seven 8-bit bytes until the end. The last set will be a incomplete one with less than 7 bytes.

        There are Lua methods done by Mauro De Carolis (who made the actual Korg 05R/W panel) which will code and decode any 7-bit worm into a proper 8-bit dump and vice-versa. Mauro published them under the GNU license, so they are freely distributable but must not be used in commercial projects. Look into the Korg 05R/W panel. Methods are called “midiToData” and “dataToMidi”.

        • This reply was modified 4 years, 9 months ago by Possemo.
        • This reply was modified 4 years, 9 months ago by Possemo.
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