[En-Nut-Discussion] Static RAM must fit in the lower 4k on-chip RAM?

Ole Reinhardt ole.reinhardt at kernelconcepts.de
Wed Nov 3 13:04:05 CET 2004


> Is this statement really true; that all the Static RAM must fit in the lower 
> 4k on-chip RAM?

No! If you have configured NutOS to use the external memeory and if you
have connected enough external memory there should be no problem.

> And “avr-size” returns
>    text    data     bss     dec     hex filename
> 107944    3830    9654  121428   1da54 rdr.elf

This is quite a lot. Do you use the Ethernut Board with 32K Ram? In this
case.

> So I am using 13484 bytes of static RAM, this is way over this 4k on-chip 
> RAM limit.

But not not bother if you have external memory connected.

> The problem that I am encountering is that the on board UART baud rate seem 
> to have changed randomly to some unknown value. This only happens when I 
> link the full application that I am porting to the NUT/OS. This does not 

> Any ideas what this problem could be?

Sounds like your memory / stack get's overwritten at some point. This
could happen if you have created a thread with too less stack memory. If
you don't create own thread be aware of the stack limit of the main
thread (512 bytes AFAIK).

Or you have some kind of buffer overflow.

Regards,

Ole

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