Table of Contents
Advertisement
MPX 1 MIDI Implementation Details
Messages
Using Control Addresses and Parameter Types, several SysEx messages have been defined to allow an
external system to learn to control and interface with another MPX 1. Five core messages are typically
used:
Request
System Configuration
Parameter Description
Parameter Type
Data Transfer
These five messages make up a basic toolkit for communicating with the MPX 1. Each message type is
given an identifying number.
Request
The Request message consitutes an external request made to an MPX 1 to respond with one of the other
message types. The Request consists of the identifying number of the message you want returned and,
any specific information the system requires to respond properly.
System Configuration Message
This message provides basic information about the target system such as software revision, date of
release and number of parameter types supported by the particular system.
Parameter Description Message
Each parameter type in the MPX 1 has a "description" that provides information about the parameter such
as its legal values. A controlling system typically "requests" the System Configuration Message to find out
how many parameter types the system supports, then requests the Parameter Description for each
parameter. A local database of parameter descriptions in the controlling system is used to build the control
tree and to edit parameters.
Parameter Type Message
After a database of parameter descriptions has been built of all parameter types, the controlling system
needs to find out what the control tree for the MPX 1 looks like and what parameter type is used at each
"node" of the tree. To do this, the controlling system "requests" the Parameter Type for a specific Control
Address.
Data Transfer Message
After the parameter type at a given control address is known, the Data Transfer Message is used to send
parameter change values to the MPX 1 or to "request" the current value. The Parameter Description tells
you the name and legal values of the parameter.
"Learning" the MPX 1
In order for a controlling system to control or interface with the MPX 1, it needs information such as the
Manufacturer ID, the Product ID and the Device ID of the system. The Manufacturer ID and the Product
ID can be acquired using the Non Real-Time System Exclusive General Information Device Inquiry. The
Device ID can be obtained from the system's user interface or by using "all devices" (127).
Building a "Parameter Description" Database
Building a control tree and editing parameters requires information about parameter types. The external
control system requests the "System Configuration Message" to tell it how many "types" the system
supports, then requests a description of each parameter. As each parameter description comes in, the
control system builds a database with them. Refer to the Parameter Description (04 hex) for additional
information about the elements of this database.
4
Lexicon
Advertisement
Table of Contents
