Appendix B: Parameter Formats - Peavey PC 1600X Mode D'emploi

ABOUT PARAMETER FORMATS
Parameter formats determine how the variable "pr" bytes in a fader string are computed by the PC 1600x. 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 PC 1600x
supports up to 4). 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 PC 1600x is able to send the data in several
formats to support the most popular translation methods. The choice of parameter format will tell the PC 1600x
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, or 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 "2Byte, 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
2 byte, 7 bits, hi to lo
2 byte, 7 bits, lo to hi
3 byte, 7 bits, hi to lo
3 byte, 7 bits, lo to hi
2 byte, Nibs, hi to lo
2 byte, Nibs, lo to hi
-This format requires only one "pr" byte and is used for numbers
ranging from 0-127 (or -64 to +63). This is the format used for most
MIDI commands.
-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.
-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.
-This format requires three "pr" bytes. It is similar to the format
"2byte, 7bits, hi to lo" except extended to three bytes. This is a rarely
used format.
-This format requires three "pr" bytes. It is similar to the format
"2byte, 7bits, lo to hi" except extended to three bytes. This is a rarely
used format.
-This format requires two "pr" bytes. The first byte contains
bits 4-7 of the parameter and the second byte contains bits 0-3
of the parameter. This is a common format used to send
parameters ranging from 0-255 or -128 to 127.
-This format requires two "pr" bytes. The first byte contains
bits 0-3 of the parameter and the second byte contains bits 4-7
of the parameter. This is a common format used to send
parameters ranging from 0-255 or -128 to 127.
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Appendix B