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RE: Use of internal and external ram


I'm using the sources provided by Carl van Shauik. I am developing the port
independently and has managed to build and tested using the examples
programs from eCos successfully.

As for the usage of RAM, is it as simple as adding a section name to those
areas which are to be located in another section in the vectors.S files then
add that section in the memory layout using the eCos configuration tool?

You mentioned about the linker script, are you referring to arm.ld in this
case? If so what should I do to this file?

Thanks
Stanley

-----Original Message-----
From: Lewin A.R.W. Edwards [mailto:larwe@larwe.com]
Sent: Monday, April 23, 2001 23:19
To: Ho Shui Choy Stanley PS03B NCS; Ecos-Discuss (E-mail)
Subject: Re: [ECOS] Use of internal and external ram


Hi Stanley,

>I am building eCos for AT91EB40

Question: Where did you get the sources for this? Is this the old archived 
port mentioned on ecos-discuss some weeks ago, or are you collaborating 
with Daniel Andersson, or are you developing an independent port?

>In my platform there is internal ram(addr 0x00100000) and external ram(addr
>0x02000000) how do I make use of both available ram?
>Is it possible to specify that the stack space resides in the internal ram
>while data in external ram?

It's certainly possible (I do something very similar on the EP7212 - user, 
FIQ, IRQ, SVC stacks are in on-chip SRAM and heap is in off-chip DRAM). 
It's just a matter of tinkering with the startup code and linker script. 
For elegant integration into eCos, especially given that most people who 
use it are going to port it to "real" hardware sometime, I would suggest 
that you expose this stuff to configtool if possible.

=== Lewin A.R.W. Edwards (Embedded Engineer)
Work: http://www.digi-frame.com/
Personal: http://www.zws.com/ and http://www.larwe.com/

"... a man who is endowed with real qualities of leadership will be tempted 
to refrain from taking part in political life; because [...] the situation 
does not call for a man who has a capacity for constructive statesmanship 
but rather for a man who is capable of bargaining for the favour of the 
majority. Thus the situation will appeal to small minds and will attract 
them accordingly."


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