[ECOS] Capacity problem?

Gary Thomas gary@mlbassoc.com
Thu Dec 19 08:03:00 GMT 2002

On Thu, 2002-12-19 at 07:50, Daniel Lidsten wrote:
> I short clarification that i missed in the first email: 
> When starting from flash then i copy all code to RAM and resume
> execution there. By doing this i can startup an image almost everywhere
> in the memory and then make it copy itself to RAM 0x0->.

Note: most PowerPC platforms have a special mode for this "ROMRAM".
You might look at some of them, e.g. the viper, to see how I've done it.

> Since i execute in RAM (even with flash startup) then i don't have any
> problems due to slow execution but maybe my CPU needs a special setup
> when executing from flash??

Are you telling eCos to run from RAM?

Also, note that I changed how caches were initialized on PowerPC
platforms on April 11.  Before that, I don't think that RAM startup
would have explicitly enabled any caches.  This is possibly a
difference between your FLASH/RAM and BDI/RAM sequences.

> > Also, on the MPC8xx, you might want to tune the number of 
> > data buffers.  The defaults I put in are very conservative 
> > and could easily be swamped.
> Yepp, i changed from 4 to 16 a while back.
> Is there anyone that has changed the startup files (vectors.S or the
> board specific file like mbx.S) to setup some special registers ?? Maybe
> i have missed some....?

Again, you might look at some of the newer PowerPC platforms for

Gary Thomas                 |
MLB Associates              |  Consulting for the
+1 (970) 229-1963           |    Embedded world
http://www.mlbassoc.com/    |
email: <gary@mlbassoc.com>  |
gpg: http://www.chez-thomas.org/gary/gpg_key.asc

Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss

More information about the Ecos-discuss mailing list