[ECOS] Re: ecos mem footprint with HTTPD support

Mandeep Sandhu mandeepsandhu.chd@gmail.com
Thu Jul 16 08:54:00 GMT 2009


>> Couldn't we have "added" RAM there?
>>
>
> That is defined in plf mlt files. I guess here for your target
> hal/arm/at91/at91sam7s/current/include/pkgconf/mlt*
>
Ok will check that. Thanks.

> [snip]
>
>> Do you think 256K RAM will be enough to run a similarly configured
>> system (with additional USB device and SPI driver support) on ARM7
>> based embedded SoC?
>
> IMO, it will be possible, if you will use lwIP TCP/IP stack.

I think I was wrongly calculating my RAM usage for the sample HTTPD
app (using lwIP).

When looking for the runtime RAM usage of my app+kernel...I should
add the bss+data+rwdata (if any) sections...right?

.text and .rodata will reside in the flash only. Am I correct in this
assumption?
Do all embedded systems work this way...i.e the code/text and rodata sections
reside in the flash and rest is loaded into the RAM? Who maps these addresses?
The linker script?

Because with this calc, my RAM requirement gets reduced drastically.

Also, any tips on how much space I should keep for expansion of the RW
area's?

Say my bss+data+rwdata comes to around 55KB...is it safe to go with a
system with 64KB on-chip RAM? Is 9KB margin safe enough?

thanks as always,
-mandeep

>
> Sergei
>

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