Appendix B: Parameter Formats - Peavey PC1600X User Manual

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ABOUT PARAMETER FORMATS
Parameter formats determine how the variable "pr" bytes in a fader string are computed by the PC1600x.
The single byte format is the most basic. It allows for 128 distinct values, usually 0 to 127 (0-7Fh in hex).
Remember a MIDI data "Byte" is essentially only 7 bits, since the eighth bit can't be set - that would make it
a MIDI "Status" byte. When this range isn't large enough, the data must be represented with more than one
byte (the PC1600x supports up to 4h, After these bytes are sent to a MIDI device, that device must translate
all the bytes into a single value.
There is no industry standard for this translation so the PC1600x is able to send the data in several formats to
support the most popular translation methods. The choice of parameter format will tell the PC1600x three
important things:
1. The number of bytes that make up the data value (1-4).
2. The size and weighting of each byte
4-Bit binary (Nibs or nibbleized).
7-Bit Binary
4-Bit BCD (Binary Coded Decimal).
3. The order of numerical significance (high to low or low to high).
To determine the proper parameter format for your receiving device. Consult your owner's manual or SysEx
documentation.
Remember to make sure that the number of "pr" bytes in your MIDI string matches the number in the
parameter format. For example, if you choose "2 Byte, Nibs Hi->lo)" you must have at least two "pr" bytes
in the string, If you choose to put more than two in the string, the 2-byte data value will repeat as necessary.
This is useful if you want to use a single fader to program two different parameters simultaneously (as long
as they have the same format and range, of course).
Single byte:
This format requires only one "pr" byte and is used for numbers ranging
+63). This is the format used for most MIDI commands.
2 bite, 7 bits, hi to Io
This format requires two "pr" bytes. The first byte contains bits 7-13 of the parameter and the
second byte contains bits 0-6 of the parameter.
2 byte, 7 bits, lo to hi
This format requires two "pr" bytes. The first byte contains bits 0-6 of the parameter and the
second byte contains bits 7-13 of the parameter. This is the format used for a MIDI pitch bend
command. The MIDI sample dump standard also specifies parameters in this format.
3 byte, 7 bits, hi to Io
This format requires three "pr" bytes. It is similar to the format "2-Byte,7-bits, hi to lo" except extended to three bytes.
This is a rarely used format.
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Peavey PC1600X User Manual (rev-h)
Appendix B
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