Looking for a free RTOS for PIC 16f877

rtos for pic 16f

Hi

I'm looking for a free rtos to use with 16f877

Freertos is for the 18f and the free version of salvo has not enougth task
thanks

Re: rtos for pic 16f

*.C or *.asm ?
Question Google :wink:
regards,

Re: rtos for pic 16f

For this series a single scheduler maybe a usefull because of the limitations features of the microcontroller CPU (without stack, litle ram e flash, etc)...
But, if You relly need the RTO´s, see SALVO in:
http://www.pumpkininc.com/

Good application notes can be found in:
www.psoc.com.br
www.microchip.com

Re: rtos for pic 16f

Try JacOS

Re: rtos for pic 16f

A real RTOS is too oversized for a small 16F*-device...
I use a timer as scheduler and set flags at the beginning and the end of each program part. This solution works without any problems, but the context saving has to be made individually and this should be the main problem.
If you only have about 3-5 tasks, that are called sporadicly, you should use this solution. If you have many different tasks, running at the same time, you should consider if the few bytes ram of the 16F*-devices will be enough or you better use an 18F*-device, where you have up to 2k ram.

There are 3 main-problems, that occur if you want to write a rtos for a pic:
- lack of timers
- lack of ram
- stack not deep enough
Everything else can be avoided, but if you want to use only 2 timers, you have to use more ram, which is not available.

So just use a simple scheduler, for details google for "round robin" or "scheduling"

I hope this helped you a bit...