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MPX 1 V1.10 MIDI Implementation Details
Parameter Name (Bytes 12-x)
This is the actual text string used to describe the parameter. Note that this string is NOT null terminated
but will often be padded with spaces (ASCII 20 hex). In most cases, these are the strings that appear on
the front panel display. Parameter types with the same names often have other attributes that are different.
Number of Bytes
This is the size of the parameter in bytes. Most parameters are 1 or 2 bytes. Parameters that are bigger
include the "Program" name, the "Setup" name and other "dump" parameters. Though not reflected in this
number, the data bytes for parameter Options are included in data messages for parameters which have
options. When dealing with Parameter Data messages, the Parameter Description for the option
parameter must be referenced to correctly interpret the data (number of bytes in the option Parameter
Type, min/max value, etc.).
Note that some Option parameter types (Rate units, Drate units, etc.) actually have 0 bytes. In these
parameters, the "data" is actually contained in the MSB of the root parameter's data. Refer to the Unique
Parameters section for additional information.
Control flags
The control flags are used to define several attributes that are either on or off (0=NO, 1=YES). The
following bits have been defined for the MPX 1:
Bit
Mask
0
0x01
1
0x02
2
0x04
3
0x08
Options Parameter Type
This defines the Parameter Type Number (ID) of the parameter's option if it exists. Options are essentially
extensions of the parameter itself. Though they have their own types, they are accessed through the
parameters. (See the Parameter Data Message.) Often the option data value must be evaluated before
a parameter value can be correctly interpreted ("Delay" units, for instance). A value of 0xFFFF indicates
that no option parameter is used.
Number of Units/Limits
Some MPX 1 parameters can operate in different "unit" types. An example of this is Delay Tme, which can
be set in milliseconds, a ratio of beats per measure relative to the current tempo, feet, meters or tapped
in milliseconds. The system only has a fixed amount of actual delay memory and the steps of each of these
represents different amounts of time so the limits for each are different. This field defines how many unit
types are available for this parameter. This value will also tell you how many mins, maxs, and display units
are included in this packet.
If the Number of Units/Limits is more than 1, the Option is used to determine which unit type is used and
what they are called. Use the String version of the Option to get a text description of the current Unit.
Minimum Value
This is the minimum allowable value for this parameter type. Note that the values are expressed as signed
words that must be cast to signed or unsigned bytes if the parameter is a single byte parameter. Also note
that the min and max values are only meaningful for 1 and 2 byte parameters. Typically, the min and max
fields are defaulted to 0x0000 and 0xFFFF respectively for "dumps".
Maximum Value
This is the maximum allowable value for this parameter type.
16
Description
Patchable
Automation (transmitted when automation is turned on)
Control level
Bottom Control Level (the last control level before an editable parameter)
Lexicon
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