User`s manual

SCIOPTA - Real-Time Kernel
User’s Manual Manual Version 4.1 15-1
SCIOPTA - Real-Time Kernel
15 Building SCIOPTA Systems
15 Building SCIOPTA Systems
15.1 Introduction
In a new project you have first to determine the specification of the system. As you are designing a real-time sys-
tem, speed requirements needs to be considered carefully including worst case scenarios. Defining function blocks,
environment and interface modules will be another important part for system specification.
Systems design includes defining the modules, processes and messages. SCIOPTA is a message based real-time
operating system therefore specific care needs to be taken to follow the design rules for such systems. Data should
always be maintained in SCIOPTA messages and shared resources should be encapsulated within SCIOPTA proc
-
esses.
To design SCIOPTA systems, modules and processes, to handle interprocess communication and to understand the
included software of the SCIOPTA delivery you need to have detailed knowledge of the SCIOPTA application pro
-
gramming interface (API). The SCIOPTA API consist of a number of system calls to the SCIOPTA kernel to let
the SCIOPTA kernel execute the needed functions.
The SCIOPTA kernel has over 80 system calls. Some of these calls are very specific and are only used in particular
situations. Thus many system calls are only needed if you are designing dynamic applications for creating and kill
-
ing SCIOPTA objects. Other calls are exclusively foreseen to be used in CONNECTOR processes which are need-
ed in distributed applications.
One of the strength of SCIOPTA is that it is easy-to-use. A large part of a typical SCIOPTA application can be
written by using the system calls which are handling the interprocess communication: sc_msgAlloc, sc_msgTx,
sc_msgRx and sc_msgFree. These four system calls together with sc_msgOwnerGet which returns the owner of
a message and sc_sleep which is used to suspend a process for a defined time, are often sufficient to write whole
SCIOPTA applications.
Please consult the SCIOPTA - Kernel, Reference Manual for detailed description of the SCIOPTA system calls.
The SCIOPTA building procedure consists of the following steps:
• Configuring the system with the SCONF configuration tool (sconf.exe see chapter 16 “SCONF Kernel Con-
figuration” on page 16-1). The SCONF tool generates the C file sconf.c (system defines and start) and the in-
clude files sciopta.cnf (not for ARM architecture) and sconf.h.
• Locate the include files and define the include paths.
• Assemble the kernel.
• Locate and get all assembler source files and assemble it.
• Locate and get all C/C++ source files and compile them.
• Design the linker script to map your system into the target memory.
• Select and define the correct libraries for the SCIOPTA Generic Device Driver (gdd) and Utilities (util) func-
tions.
• Link the system.
The Getting Started project (see chapter 3 “Getting Started” on page 3-1) is a good example for the needed files of
a SCIOPTA application. This example project as a good starting point for your system design.