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Re: interrupt/virtual vectors confusion
- From: Andrew Lunn <andrew at lunn dot ch>
- To: Matt Sartori <msartori at hanoverdisplays dot com>
- Cc: eCos Disuss <ecos-discuss at ecos dot sourceware dot org>
- Date: Wed, 17 Aug 2005 11:08:36 +0200
- Subject: Re: [ECOS] interrupt/virtual vectors confusion
- References: <F9885E669725F248A1F6DB9109FDD67905E4D9@Molly.hanover.local>
On Wed, Aug 17, 2005 at 08:40:25AM +0100, Matt Sartori wrote:
> I'm not sure I understand how this would work. Switching my board into
> RAM boot mode means that it maps internal RAM (0x20000000) to
> 0x00000000. On reset it always start execution from 0x0 but will in this
> case find nothing there to execute. On the other hand if booting in the
> boards normal mode (USER mode with flash mapped to 0x0) it will boot
> fine but when your app wants to change the vector at 0x18 it, as you
> pointed out, fail to do so.
> Jumping into high address mapping (by that I understand that when an
> exception/interrupt occurs all the instructions in the vector at 0x0
> jump to another vector in RAM) is what I want to do but still haven't
> quite worked out where to do - presumably by changing the vector setup
> of Redboot.
Can you change the mode on the fly? Normally you start with ROM at
address 0x0 and them move it out of the way and put RAM there. See if
this is possible with you hardware.
Andrew
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