[En-Nut-Discussion] RAM usage for NUT/OS (Re-sending)

[Ernst Stippl]

Hi!

I think the most complex parts to port are

- Nut/OS thread creation/switching (how the stackframe has to be set up)
  because that's tightly copled to HW architecture, so oyou have to
understand the CPU, registers etc and how the compiler uses them
- the initializing of ram, variables, etc beause thats usually done by the
compiler'd prefabricated runtime/init routines
- Nut/Net Ethernet driver because it depends on the chipset in use.
  
I have found that it helps enormously to be familiar with the source
platform, because it allows to "extrapolate" how various things need to be
re-implemented on the target platform.

How long it will take? Well, it depends how much of your spare time you can
dedicate. Maybe 100 hours for a basic port including an uart, timer,
threads, the necessary os libs and structures??

regards
Ernst

-----Ursprüngliche Nachricht-----
Von: en-nut-discussion-bounces at egnite.de
[mailto:en-nut-discussion-bounces at egnite.de] Im Auftrag von D T
Gesendet: Montag, 19. Mai 2008 16:28
An: Ethernut User Chat (English); Ole Reinhardt
Betreff: Re: [En-Nut-Discussion] RAM usage for NUT/OS (Re-sending)

Thanks for your reply.
I now have a clearer picture.

I have looked at the uip and lwip stacks, I think I might use one of them
for now.

But, can you estimate how much will it take to port NUT/OS on AVR32?
I am thinking of working on this port in my free time. It should be a good
exercise learning about the RTOS and know some details about the TCP/IP
stack imlpementation.

Thanks,
drt



--- On Mon, 5/19/08, Ole Reinhardt <ole.reinhardt at embedded-it.de> wrote:

> From: Ole Reinhardt <ole.reinhardt at embedded-it.de>
> Subject: Re: [En-Nut-Discussion] RAM usage for NUT/OS (Re-sending)
> To: drt80_forum at yahoo.com, "Ethernut User Chat (English)" 
> <en-nut-discussion at egnite.de>
> Date: Monday, May 19, 2008, 7:49 AM
> Hi,
> 
> > I have an upcoming project based on AVR32. The project
> will have TCP/IP stack along with other features.
> 
> AFAIK there currently is no port of NutOS / NutNet for the
> AVR32
> platform available. But feel free to do this task :)
> 
> > I need to incorporate a TCP/IP stack and Nut/Net seems
> to be a good
> >  choice right now. I would be using TCP, UDP and HTTP.
> The code size
> >  will not be an issue (have plenty), but have a
> limited amount of RAM
> >  of 64K. With all the applications in the project the
> around 25K RAM
> >  will be left for TCPIP.
> 
> Yes, 25K should be sufficient for TCP/IP using NutNet. I can't give 
> you a correct value of what will be needed as this depends much on the 
> network driver you use (does your network controller has it's own 
> packet buffer or do you need to use system ram) and the variable sizes 
> in your system (32 bit I expect?). So all in all it should be 
> comparable with the ram usage an the arm plattform. I even have no 
> value for that platform, but I'm shure harald can give you some memory 
> usage statistics.
> 
> > The project does not require a RTOS. Is it required to
> use NUT/OS to
> >  use the TCPIP stack? Is the stack single threaded?
> 
> If you don't want to use any RTOS at all, you should better take a 
> look on lwip or uip for example.
> 
> http://www.sics.se/~adam/uip/index.php/Main_Page
> http://www.sics.se/~adam/lwip/links.html
> 
> NutNet is not single threaded and at least needs a running NutOs 
> kernel.
> 
> Regards,
> 
> Ole Reinhardt
> 
> --
> 
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