RTEMS or FreeRTOS on STR712FR (ARM7 TDMI)

Marchaudon Romain Guest 2010-04-15 10:10 #1675010

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Hi everyone,

I was looking into some informations about the possibility to use RTEMS 
on a tiny µC with an ARM7TDMI included (this is the STR712FR, but for 
the moment I don't know if it's the 0, 1 or 2 ...)

I have seen that this is possible to reduce the size of the kernell with 
RTEMS, but I still don't know how many KB of RAM and flash I need to 
make it run :S

Also what do you think about FreeRTOS? Better that RTEMS on a µC?

I'm sorry but this is the first time in my life I have to use a RTOS 
(I'm a trainee ...) and I'm getting issue finding those informations.

Thans a lot.

Romain

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Romain R. (heero_91) (Company: Viveris Technologies) 2010-04-15 16:15 #1675679

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I have had the information from my project manager, the µC is the 
STR712FR2 which have 256+16 KB of flash and 64 KB of RAM.

So do you think this is possible to put RTEMS or I should use FreeRTOS 
or µClinux?

By the way, why the flash memory is presented as 256+16? What's the 
interest?

Thanks a lot

Romain

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Romain R. (heero_91) (Company: Viveris Technologies) 2010-04-20 14:51 #1681444

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no-one can answer me? For the moment I can't test on my hard (I'll 
receive it in few weeks) but I need to know in order to devellop 
properly.

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Martin T. (mthomas) Moderator 2010-04-20 17:17 #1681657

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Since you did not mention external Flash- and RAM-Memory I don't think 
there is a chance to get ucLinux working. I have not worked with RTMS 
but as far as I know it also needs more memory as the controller offers 
internally.

FreeRTOS should be o.k. if you need a small, well-documented and free 
RTOS. You may take a look on ChibiOS/RT which offers similar 
functionality and a comparable license.

Please note that uClinux and RTMS offer a lot of more functions and 
drivers. But it's not that difficult to extend the STM STR7-StdPerphLib 
with synchronisation-code (e.g. mutexes) in case different tasks/threads 
access the same peripheral. Using the STM-STR7-Library as base should 
save some time.

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900ss Guest 2010-04-20 18:18 #1681742

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Martin Thomas wrote:
> You may take a look on ChibiOS/RT which offers similar
> functionality and a comparable license.

Martin, do you have experience with the ChibiOS/RT? It looks interesting 
but I didn't find the time to run a test.
If you have experience, are you satisfied with that OS? Can you suggest 
it?
Thanks, 900ss

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Romain R. (heero_91) (Company: Viveris Technologies) 2010-04-28 10:07 #1690916

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Hi,

Sorry to "UP" this topic but I'm still on the choice of the OS so far on 
the project (I'm not making the choice, just doing the research, my 
project manager is making the choice).

With your informations and others I have found on the Internet, I can 
say that RTEMS will not be abloe to run on my µC!

But you have said that I should have a look on uClinux, and this is what 
I am doing ... And I have seen that it still needs too much memory 
(arround 500KB apparently ... But I am not sure). Anyway the interesting 
part is that I can use a dbg with this OS, which is very interesting, 
but with the memory problem so far I should not be able to use the OS on 
my board :(.

I know that there is, on uClinux, a TCP/IP stack, and I don't need this. 
Is there any way to remove component from uClinux in order to decrease 
the size ok the kernel? I can't find info about this on the uClinux 
website so far, and I'm still searching!

Or maybe I'm just wrong and this is possible to run directly uClinux on 
256+16 KB of flash and 64 KB of RAM, inernal to my µC?

Thanks a lot for your answers.

Romain Marchaudon

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