[En-Nut-Discussion] Memory Question

[Ralph Mason]

Hi, I have done page extensions to Nut OS

The extensions allow each thread to run in one or more banks, my board has
128kb of ram with 3 2kb pages allowing a thread to have 2,4 or 6 kb of ram.
You can create a thread with a paged or non paged stack. The board has 128kb
of ram (64 pages). (Memory map 0-0xdfff ram, e000-e7ff page1, e800 - efff
page2 , f000-f700 page3 , f800 - IO space including page registers )

It all works quite well, it does mean that threads can't access stuff on
another threads stack but that isn't really a problem. The way the driver
work they are always copying from heap allocated memory to a thread supplied
buffer, in the context of the calling thread.

The basic outline is each thread has a number of page slots (in my case 3)
these get written to the page register on each context switch.

I have some simple page allocation / deallocation functions, so a thread can
request a page and assign it to one of it's slots.  Threads could both share
pages also.

If its of any use I can sent the files.

Regards
Ralph


> -----Original Message-----
> From: en-nut-discussion-admin at egnite.de
> [mailto:en-nut-discussion-admin at egnite.de]On Behalf Of Harald Kipp
> Sent: Saturday, 10 May 2003 9:44
> To: en-nut-discussion at egnite.de
> Subject: Re: [En-Nut-Discussion] Memory Question
>
>
> Hi Martin,
>
> I'm still waiting for the final Ethernut 2 prototype PCBs.
> Ethernut 2 is equipped with 512k RAM. If the prototype
> works as expected, we will be able to ship the final boards
> within a few weeks. If not...well.
>
> It is possible to expand the RAM via expansion connector.
> Jepser Hansen did this once on the first MP3 add-on, he
> designed and it worked. But it was scraped later, because
> the MP3 software didn't need the extra 32k RAM when running
> in a LAN and would have required much more RAM for streaming
> MP3 over the Internet.
>
> Harald
>
> At 23:32 09.05.2003 +0200, you wrote:
> >Hello,
> >
> >Although I am pretty much a newbie regarding hardware design and
> >microcontrollers, I am planning to accuire an Ethernut device. Therfore I
> >have some questions regarding the maximum amount of memory the Ethernut
> >has built in / supports. I belive there was a version with 128kbyte sram
> >announced, and the proposals in the "Memory Consideration" guide about
> >bank-switched ram seem promising, so is it forseeable when such a version
> >might be available? Or will it be possible to extend the memory of the
> >current Ethernut version (1.3F) via the expansion slot, or has anyone
> >already developed such an extension?
> >
> >With kind regards,
> >  Martin
> >
> >_______________________________________________
> >En-Nut-Discussion mailing list
> >En-Nut-Discussion at egnite.de
> >http://www.egnite.de/mailman/listinfo/en-nut-discussion
>
> _______________________________________________
> En-Nut-Discussion mailing list
> En-Nut-Discussion at egnite.de
> http://www.egnite.de/mailman/listinfo/en-nut-discussion
>
> ---
> Incoming mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.461 / Virus Database: 260 - Release Date: 10/03/2003
>
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.461 / Virus Database: 260 - Release Date: 10/03/2003