[ECOS] ARM - RAM region at other address than 0

Backhaus Willy w.backhaus@newage-avkseg.com
Mon May 19 14:20:00 GMT 2003


hello,

> -----Original Message-----
> From: Doyle, Patrick [mailto:WPD@dtccom.com]
> Sent: Monday, May 19, 2003 4:03 PM
> To: 'Backhaus Willy'; ecos-discuss@sources.redhat.com
> Subject: RE: [ECOS] ARM - RAM region at other address than 0
>
>
> I am pretty sure that the '5471 offers a mechanism for
> swapping ROM and
> SDRAM at address 0.  I haven't looked at it in ages, but this
> is a common
> "problem" with ARM based processors and they share a common
> solution -- the
> ability to swap what shows up at address 0.


I really don't know how! I think it can neither swap chip selects in
general, without external logic. and it can only boot from chip select 0
that is hard wired to address 0.

Regards,

Willy






> > -----Original Message-----
> > From: Backhaus Willy [mailto:w.backhaus@newage-avkseg.com]
> > Sent: Monday, May 19, 2003 9:26 AM
> > To: ecos-discuss@sources.redhat.com
> > Subject: [ECOS] ARM - RAM region at other address than 0
> >
> >
> > hello,
> >
> > we have an board with an ARM7TDMI (Texas Instruments -
> > TMS320VC5471) core
> > where the ROM (flash) starts at address 0 and RAM (actually
> > SDRAM) beginns
> > at address 0x10000000. this mapping can't be changed. I saw
> > in vectors.s
> > (for ARM) that, it is presumed that the RAM region always
> > starts at address
> > 0. some of the exception vectors are copied from the
> > __exception_vectors
> > label to address 0 + offset.
> >
> > to port eCos, do I have to change vectors.s to copy the
> > __exception_handlers
> > to other address than 0? or it's possible to obtain this with
> > a processor
> > specific HAL?
> >
> > thank you.
> >
> > Regards,
> >
> > Backhaus Willy
> >
> >
> > --
> > Before posting, please read the FAQ:
> > http://sources.redhat.com/fom/ecos
> > and search the list
> > archive: http://sources.redhat.com/ml/ecos-discuss
> >
>


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