RE: [ECOS] interrupt/virtual vectors confusion

["Matt Sartori" <msartori at hanoverdisplays dot com>]

Fantastic! I didn't know you could do that in software since my board
has switches on to change modes. A quick focused search through the
reference manual did indeed reveal the ability to switch modes on the
fly and even mentions that this is useful for managing interrupt
vectors. Finally the answer I was looking for :)
Thanks Andrew.

-----Original Message-----
From: Andrew Lunn [mailto:andrew@lunn.ch] 
Sent: 17 August 2005 10:09
To: Matt Sartori
Cc: eCos Disuss
Subject: Re: [ECOS] interrupt/virtual vectors confusion

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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