Preamble

Release includes a sample set that contains three samples and RTOS sources. The purpose of the sample set is to show use examples and primary RTOS functionality and features.

General Description

RTOS consists of three parts:

• Common part;
• Target-dependent part;
• Project-dependent part.

Common part contains main RTOS definitions and declarations such as RTOS kernel, interprocess communication services and little support library. All Common sources stand at Common subfolder (see below).

Target-dependent part describes target processor and toolkit features of the RTOS:

• Target-level configuration macros;
• Critical section definition;
• Some performance-critical functions;
• Interrupt and interrupt service routines support;
• Target processor specific process's constructor;
• Idle process declaration.

Project-dependent part includes two header files:

• scmRTOS_CONFIG.h;
• scmRTOS_TARGET_CFG.h.

scmRTOS_CONFIG.h describes project-level RTOS configuration macros.

scmRTOS_TARGET_CFG.h contains project-level tuning code, in particular System Timer and context switch software interrupt stuff. Default, WatchDog Timer is used as System Timer, and Analog Comparator Interrupt as Software Context Switch Interrupt. The user can change these setting to more project-suitable if need.

Sample Structure

The sample consists of three parts:

• EventFlag.
• message.
• channel.

EventFlag sample brings test on speed. OS::TEventFlag is the simplest and fastest service of the RTOS. In this example program control flow transferred from timer interrupt service routine (ISR) to waiting process. Dedicated processor's pin is set to '1' before signalling of the EventFlag and set to '0' inside waiting process. So, positive pulse width on this pin corresponds with program control flow transfer time. Another five pins are set to '1' or '0' on various events, detailed description and oscillograms see in ./1-EventFlag/doc/1-EventFlag-scope.html

OS::message sample demonstrates ability to send arbitrary information from ISRs and processes to processes. In the example one process waits the message and timer ISR and another process send the message. Message content is different in each case, so, process-receiver can distinguish the source of the message.

Sample with OS::channel shows a message queue. Since the message can have arbitrary type, current example uses pointers to class types. In the example two more priority processes "delegate" some actions to the third (low-priority) process. See scmRTOS documentation Appendix section for more details about this mechanism.

Contents of all parts is the same: test project and RTOS sources. Each located in its own folder.

Structure of test project folder (folders are in brackets '[]'):

[makefiles]       - common project-independent makefiles for avr-gcc and avreal
[src]             - test project sources
[exe]             - executable product[s]
[lst]             - listings and other temporary text files
[obj]             - objects and other intermediate files
makefile	  - project make script

folders [exe], [lst], [obj] are not saved in repository and created during compilation process

Structure of the RTOS folder:

scmRTOS
  Common           - common RTOS sources
  AVR              - portable part

Usage

AVR/GCC port intended to be used with avr-gcc v3.4.x and later versions. Work with versions before v3.4 not tested, versions before 3.0 are not supported.

There are two variants of usage. The first variant is checking out sample set from the SourceForge repository. The second one is downloading the release archive and using it locally.

Building

$PROMPT$>make

$PROMPT$>make run

AVRGCC=c:/WinAVR-20071221

MAKE_SMALLEST_HEX = Y

TRG = message

MCU := atmega168

TRGPGMEXT = hex eep

FUSES = bodlevel=5,cksel=2,ckdiv8=off,sut=0

AVREAL_OPT= -n

F_CPU=8000000

Another variables are clear for gcc users.