General AMX Operation
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2.2 AMX Operation
AMX Startup
Each AMX-based system consists of the AMX executive program and a set of
application tasks and interrupt service procedures. This collection of programs resident
in the memory of the microprocessor configuration represents the entire operating
system.
The manner in which the operating system begins execution is application dependent. In
ROM-based systems, automatic hardware vectoring to the program start address is often
implemented. In RAM-based systems, the program is first loaded from some storage
medium (ROM, hard disk, diskette, etc.) or downloaded from one processor to another.
Once the program is loaded, it is started at its start address by the loader.
Figure 2.2-1 illustrates the general operation of an AMX system. Execution begins in the
user domain providing the opportunity for hardware specific and application dependent
setup prior to the initialization of the AMX system. For example, hardware interfaces
may require custom configuring. In some systems, it might be desirable to perform a
memory integrity check before system startup is permitted.
Once all custom initialization has been performed, the program calls the AMX entry
procedure ajentr. Operating characteristics are defined in an AMX S ystem
Configuration Module. It is possible to predefine specific tasks and timers which will be
automatically created by AMX during its initialization phase. AMX initializes itself and
places all application tasks and timers into an idle state.
Once AMX has initialized all of its internal variables and structures, it executes a
sequence of user provided Restart Procedures. These procedures can invoke AMX
services to start tasks and initialize interval timers.