Lexicon MPX 1 - MIDI IMPLEMENTATION DETAILS Midi Implementation Manual page 9

MPX 1 MIDI Implementation Details
Once you have access to the description of the parameter at the top of the control tree, the description
contents is used to build the tree below it. Each of the descriptions contains a "min" value and a "max"
value. For parameters such as "Mix" that can be edited, these are the maximum mix value (100) and the
minimum mix value (0) to which the parameter can be set. When the parameter type is not an editable
parameter, the min and max represent the tree branches below it. A parameter is considered editable if
the "Control Level" flag in the parameter description Control Flags field is NOT set (see Parameter
Description (04 hex). For these parameter types the min value is always 0 and the max value is always
the number of branches below it, minus 1. The min and max values represent the minimum and maximum
branch (level value) that can be accessed below it. In the case of the top level parameter, the max value
is the largest level 'A' Control Address value allowed.
When the controlling system knows how many level 'A' parameters are allowed, it can work with those
branches. In the MPX 1, it the max value under the top level parameter type is 1. This means that level
"A" can be 0 or 1. The controller would then request the parameter "type" at control address A:0 (A = 0)
as follows:
request
——header—— class
F0 06 09 00 06 03 00
The MPX 1 would send back the parameter type at that Control Address (0x0153, the "Program"
parameter). In the MPX 1, this parameter has a max value of 19. This means that control addresses A:0
B:0 through A:0 B:19 are legal so you can request parameter types for these addresses. In the next
request you would go one level deeper:
request
——header—— class
F0 06 09 00 06 03 00
The MPX 1 system would send back the parameter type at that control address (0x014D, the "Pitch"
parameter). In the MPX 1, this parameter has a max value of 10. This means that control addresses A:0
B:0 C:0 through A:0 B:0 C:10 are legal so you can request parameter types for these addresses.
This continues deeper and deeper into the control levels (letters) until you reach an actual editable
parameter. At this point you have reached the end of the branch so you go to the next value of that level.
In the MPX 1, the entire first branch looks like this:
Control level
A B
| |
MPX 1
0 - Program
0 - Pitch
6
Num Control
levels
01 00 00 00 00 00 00 00 F7
Num Control
levels level A
02 00 00 00 00 00 00 00
C D E
| | |
0 - no effect
0 - Mix
level A
level B
00 00 00 00 F7
F G H
| | |
Lexicon
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