Re: [ECOS] AT91 extended internal SRAM

["Deli Geng \(David\)" <deli dot geng at ncl dot ac dot uk>]

----- Original Message -----
From: "Jonathan Larmour" <jlarmour@redhat.com>
To: "Robert Martin" <rmartin_ecos@yahoo.com>
Cc: "eCos Discuss" <ecos-discuss@sources.redhat.com>
Sent: Tuesday, January 08, 2002 6:02 PM
Subject: Re: [ECOS] AT91 extended internal SRAM


> Nope. However you could also consider using the MMU to map it contiguously
> with the rest of RAM that also has the advantage of solving the "allow
> RedBoot to know about it" problem.

AFAIK, there is no MMU on AT91M40x MCUs. Also i think, because there is a
gap between on chip memory space and user memory space using nCSx, it is not
easy to make them contiguous by configuring EBI registers. If anyone has
done it successfully, please let me know.

>
> Again not an issue if mapped contiguously. But otherwise, I wouldn't worry
> about adding a new mode - if someone wants to use it they easily can.
>
>
> Indeed most MMUs support this type of thing (to support copy-on-write) -
it
> isn't specific to this region. I think if anyone wants it, they'd want to
> do it in their application as it depends what they're putting in it (and
> after all as you say it's only 128k).

several years ago, i used a kind of C tool kit for MCS51 MCUs. Its linker
can make one memory region across several memory areas. Do you remember in
MCS51 MCU, there are first 4 banks register memory, followed by bit
accessable memory (16 bytes :-P) and then normal internal SRAM. The linker
was designed to make most of those small memory. I just wondered if GNU
linker does or can also have similar function?

>
> Jifl
> --
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