RTOS for Dummies like me

Hi all,

RTOS seems to be doing rounds nowadays. For understanding the rtos i read some books, browsed in rtos sites such as freertos.org, ucosII, etc. Read books to understand concepts such as preemptive kernel, semaphores etc.,. But, still I am totally unaware of how to implement an RTOs, may be definitely due to my ignorance.

1. Is an rtos a set of library functions which have to be called at appropriate places in the code to create tasks, maintain timing etc.?
2. Let's say I have a code of a timer used with a 8 bit timer and display the time in the LED 7 segment display. where will this rtos code reside and how will it interface with my code?
3. How is it practically done.

Can someone throw some light on this please?

Regards

Vasan

Do you have a MCU platform you can use to try out some code? Sometimes just trying out a "test" application can help you to understand.

There's several code projects to start with that can teach about the concepts. The book by Jean Labrosse at Micrium is very good. He's also published several "ready to run" projects that work on our development boards.

Off the top of my head, I think we have H8 and M16C projects with Micrium, XMK and uExec (which is a preemptive scheduler).

Previously Jayaraman.K.Vasan wrote:

Hi all,

RTOS seems to be doing rounds nowadays. For understanding the rtos i read some books, browsed in rtos sites such as freertos.org, ucosII, etc. Read books to understand concepts such as preemptive kernel, semaphores etc.,. But, still I am totally unaware of how to implement an RTOs, may be definitely due to my ignorance.

1. Is an rtos a set of library functions which have to be called at appropriate places in the code to create tasks, maintain timing etc.?
2. Let's say I have a code of a timer used with a 8 bit timer and display the time in the LED 7 segment display. where will this rtos code reside and how will it interface with my code?
3. How is it practically done.

Can someone throw some light on this please?

Regards

Vasan

There is an RTOS available for the EDK38024, which has a 7-segment x 4 segments display. The RTOS is called uC/OS-II and is free for non-profit/academic uses. http://www.micrium.com/downloads/appnotes/EDK38024-uCOS-II.ZIP ...contains the entire RTOS in source code and an SRECORD file that can easily be flashed onto the board that demonstrates the RTOS running and data output on the display. Check with Renesas about how to obtain an EDK38024 board. Take Care. Rob!

Previously Jayaraman.K.Vasan wrote:

Hi all,

RTOS seems to be doing rounds nowadays. For understanding the rtos i read some books, browsed in rtos sites such as freertos.org, ucosII, etc. Read books to understand concepts such as preemptive kernel, semaphores etc.,. But, still I am totally unaware of how to implement an RTOs, may be definitely due to my ignorance.

1. Is an rtos a set of library functions which have to be called at appropriate places in the code to create tasks, maintain timing etc.?
2. Let's say I have a code of a timer used with a 8 bit timer and display the time in the LED 7 segment display. where will this rtos code reside and how will it interface with my code?
3. How is it practically done.

Can someone throw some light on this please?

Regards

Vasan

You can access my thesis at this link:

http://www.alessandrocasoni.it/polverari.html

sorry but is only in italian.

I've worked with Micrium for Renesas Starter Kit SH2A 7201.

In Appendix there's all C code.

Control Task, semaphore, Communication Task, ADC, MTU2 (pwm)...

Ciao from Italy

massimo

Our RTOSes  called DSPnano for 16 bit processors and Unison for 32 bit processors offer complete explanations of how they should be used and 20 or so out of the box and running examples for each processor port.   There is a number of Unison ports and one DSPnano port in the works.  They offer a tiny tiny embedded Linux or POSIX compatible RTOS without GPL.

http://rowebots.com/products/unison

 

http://rowebots.com/products/dspnano

 

http://rowebots.com/Embedded_Processor_support/renesas_m16c_development

 

http://rowebots.com/Embedded_Processor_support/renesas_H8SX

 

http://rowebots.com/Embedded_Processor_support/renesas_R32

 

 

And the documentation is on line here:

 

http://rowebots.com/downloads/DSPnano_Tutorial_GuideE8sec.pdf

http://rowebots.com/downloads/DSPnano_Programmers_Guide_E1sec.pdf

http://rowebots.com/manpages/help_index.html

 

or

 

http://rowebots.com/downloads/Unison_Tutorial_GuideE5sec.pdf

http://rowebots.com/downloads/Unison_Programmers_Guide%20E3sec.pdf

 

 

Please contact us for any clarification of any items.

 

Kim