National Instruments AutoCode NI MATRIX - Manual (Page 115)

Chapter 5 Generated Code Architecture
© National Instruments Corporation 5-7 AutoCode Reference
Figure 5-1 illustrates the interface layers. The layers are described in the
subsections shown in the figure.
Figure 5-1. Interface Layering Diagram
Scheduler External Interface Layer
This layer refers to the data directly interfacing with hardware or some
other entity not modeled within the SystemBuild model. This layer is
represented as two arrays of floating-point numbers, one for external inputs
(called
ExtIn ) and another for external outputs (called ExtOut ).
System External Interface Layer
This layer uses two structures, Sys_ExtIn and Sys_ExtOut , to
respectively represent the system external inputs and outputs. Normally,
the
Sys_ExtOut structure is optimized out because the scheduler external
outputs are taken from a subset of the subsystem’s external outputs. A
special quality of the System external structures is that the members of
those structures are ordered relative to the Top-Level SuperBlock. In other
words, for example, the fifth external input of the Top-Level SuperBlock
will appear as the fifth variable within the structure. This layer is needed
because this layer represents the actual data types as specified relative to
the Top-Level SuperBlock. Therefore, data copied into and out of this layer
is subject to a data type conversion into the all-float Scheduler interface.
Scheduler Exter
nal Input
Syst
em Exter
nal Input
External
Input External
Output SUBSYSTEM
External
Input External
Output SUBSYSTEM
Scheduler Exter
nal
Output
#1
#2 System Exter
nal
Outpu
t