[ECOS] TCP/IP on Olimex - sam7-ex256

Andrew Lunn andrew@lunn.ch
Sun May 11 13:13:00 GMT 2008


On Thu, May 08, 2008 at 02:23:28PM -0400, Ormund Williams wrote:
> Hi All
> 
> Has anyone got any of the tcp/ip stacks running on the above dev board?
> When I try to compile any of the examples it fails to link with the
> error: "section .bss is not within region ram".
> 
> Is the a way to reduce the amount of ram required? Any tips welcomed.

I know of people who have used lwip on this device. 

The LWIP stack has lots of configuration options which will affect
memory usage. Do you need TCP? No, then remove it. How many TCP
connections do you need? Change CYGNUM_LWIP_MEMP_NUM_TCP_PCB etc.

What i sometimes do in situations like this is edit the linker script,
target.ld, to give it more memory than there actually is, just so that
it will link. Then use arm-elf-nm or arm-elf-objdump --syms to look at
the size of the symbols. Find the big ones and try to optimize
them. Often the symbols causing the problem are not where you expect
them.

        Andrew

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