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Re: ARM - RAM region at other address than 0
- From: Grant Edwards <grante at visi dot com>
- To: "Doyle, Patrick" <WPD at dtccom dot com>
- Cc: 'Backhaus Willy' <w dot backhaus at newage-avkseg dot com>,ecos-discuss at sources dot redhat dot com
- Date: Mon, 19 May 2003 15:33:39 -0500
- Subject: Re: [ECOS] ARM - RAM region at other address than 0
- References: <F18ED44D2778844592DFB732956B66516ED169@DTCNT40S4>
On Mon, May 19, 2003 at 04:11:38PM -0400, Doyle, Patrick wrote:
> I glanced at the '5471 data manual and I don't see the
> "mechanism for swapping ROM and SDRAM at address 0" that I was
> expecting to see... Hmmm.... Perhaps you should ask TI about
> this. eCos really likes to see interrupt vectors in RAM.
At one point I had a hacked version of vectors.S that worked
with ROM at 0. It did the "double vector" thing (not very
pretty). After tiring of the requirement to maintain my own
vectors.S, I finally swapped ROM/RAM -- life is easier that
way.
If the 5471 doesn't have some sort of software-controlled
chip-select logic, then when you lay out your board you should
add a couple gates to allow two of the chip selects to be
swapped.
--
Grant Edwards
grante@visi.com
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