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problems with MMU and Redboot
- From: <miguelon at tiscali dot it>
- To: ecos-discuss at ecos dot sourceware dot org
- Date: Fri, 18 Aug 2006 12:46:47 +0200 (CEST)
- Subject: [ECOS] problems with MMU and Redboot
- Reply-to: <miguelon at tiscali dot it>
- Xoriginalsenderip: 194.171.252.108
Hi,
I'm working on a at91rm9200ek board (with the commercial version of
eCos, of course you can't have the code so let's take as example the
aed2000 board which looks similar as for the code) and I need to map an
external device (a radio module) on the memory. After some attempts to
set the MMU at the application side I decided to make a new platform,
following the "how to" in the Massa's book, and then I modifiy directly
the MMU table in the file
/hal/arm/arm9/aaed2000/v2_0_43/src/aaed2000_misc.c adding these two
lines (the addresses are referred to my board):
_MMU(0x500, 0x500, 1, _UNCACHEABLE, _UNBUFFERABLE,
_PERM_RW_RW); /* Radio Module HI */
_MMU(0x600, 0x800, 1, _UNCACHEABLE, _UNBUFFERABLE,
_PERM_RW_RW); /* Radio Module DCI */
Then I build a default eCos library and I compile my application which
just reads and writes from these two memory locations. The problem is
that nothing is appearing on my scope and when I try to view these two
memory locations (0x80000000 and 0x50000000) with gdb it answers me
that I'm not allowed to have access. Is then Redboot and not eCos which
enable and menage the MMU? The second test that I made was to build a
new redboot image with those modifications on the MMU table. Following
the redboot guide I obtained a bin file and I downloaded it on the
board. All seem to work correctly (I have the RedBoot prompt when I
reset the board) but when I try to debug my application with gdb I got
this message:
(gdb) target remote /dev/ttyS0
Remote debugging using /dev/ttyS0
Couldn't establish connection to remote target
Malformed response to offset query, qOffsets
I also noticed that my bin file is smaller then the one I found ready
on the eCos installation, which works correctly. So is there something
wrong in what I did? Thanks for the help.
Michele
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