[ECOS] memory maps, linker control files, etc.

Andrew Lunn andrew@lunn.ch
Thu Sep 29 10:56:00 GMT 2005


On Wed, Sep 28, 2005 at 08:10:19PM -0600, Gary Thomas wrote:
> On Wed, 2005-09-28 at 16:56 -0700, Andrew Voelkel wrote:
> > >> So the ROMRAM or RAM versions of redboot cannot be used to load and debug
> > >> ECOS programs? I don't remember reading that anywhere. But of course I've
> > >> been reading so much new stuff, I may have not have noticed it.
> > >
> > >Not correct.  ROMRAM is used for RedBoot (or any monitor) and is 
> > >perfectly suited for loading RAM programs.  RAM mode is designed for
> > >general eCos applications.
> > >
> > >The ROMRAM and RAM loader templates (.ldi files) are structured so that
> > >memory used by one does not conflict with the other.  In most cases, 
> > >ROMRAM uses a chunk of low memory and RAM version are allowed to use
> > >everything else.
> > 
> > Let's see if I've got this straight:
> > 
> > 1. The ROMRAM and RAM memory "loader templates" don't interfere, so a ROMRAM
> > monitor can be used to load/debug a RAM ECOS program.
> > 
> > 2. The ROM and RAM memory "loader templates" don't interfere, so a ROM
> > monitor can be used to load/debug a RAM ECOS program.
> > 
> > 3. Because the "loader templates" interfere, a ROMRAM monitor cannot be used
> > to load/debug a ROMRAM ECOS program.
> > 
> > 4. Because the "loader templates" interfere, a ROM monitor cannot be used to
> > load/debug a ROMRAM ECOS program.
> > 
> > 5. The "loader template" consists of the .ldi file and the memory layout
> > header file, both in the same folder. The value of HAL_STARTUP determines
> > which "loader template" to use.
> > 
> > Correct?
> 
> Yes to all.  ROM and ROMRAM modes are only suitable for either a "ROM"
> monitor (like RedBoot) or a fixed application (where the target runs 
> nothing other than that application).  RAM mode is used for more dynamic
> setups, e.g. development and testing of new applications.

I would add that that, that this is only correct for the default
configuration. It would be easy to edit the configuration so that for
example a ROMRAM monitor could execute a ROMRAM application. Just
modify the memory layout so they don't overlap...

        Andrew

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