MICROBLAZE: Using external instruction memory

Hi Arkaitz,

arkaitz wrote:
> Hi Antti,
> 
> I've done a flash loader but I don't know which file do I have to
> store in flash in order to enable to execute it.
> 
> I've proved storing the "executable.elf" file which contains the
> crt0.o initialization code linked and then I jump to that address from
> a program stored in the Block RAMS, but as I supposed it doesn't work.

re-reading your messages, it occurs to me - are you hoping to execute 
the code directly from the flash?  In that case, you will need a custom 
link script, because otherwise your data segment (read/write) will also 
be located in the flash address space, and of course that won't work at all!

In my applications I simply use the flash as somewhere to store the 
image when the power is off - at bootup I copy the image from flash, 
down into RAM to the address at which it was originally linked, then 
jump to it.  You will need to modify this sequence somewhat...

Regards,

John

Hi John,

My first idea was to execute it directly from flash memory, but now I
will first try copying to it SRAM before I execute it.

I will use an specific linker script later to execute it directly.

I have resolved the problem. Was that I was creating the elf file in
XMDSTUB mode instead of EXECUTABLE mode.

Thanks a lot for your time.

Arkaitz.

John Williams <jwilliams@itee.uq.edu.au> wrote in message news:<bm564s$d66$1@bunyip.cc.uq.edu.au>...
> Hi Arkaitz,
> 
> arkaitz wrote:
> > Hi Antti,
> > 
> > I've done a flash loader but I don't know which file do I have to
> > store in flash in order to enable to execute it.
> > 
> > I've proved storing the "executable.elf" file which contains the
> > crt0.o initialization code linked and then I jump to that address from
> > a program stored in the Block RAMS, but as I supposed it doesn't work.
> 
> re-reading your messages, it occurs to me - are you hoping to execute 
> the code directly from the flash?  In that case, you will need a custom 
> link script, because otherwise your data segment (read/write) will also 
> be located in the flash address space, and of course that won't work at all!
> 
> In my applications I simply use the flash as somewhere to store the 
> image when the power is off - at bootup I copy the image from flash, 
> down into RAM to the address at which it was originally linked, then 
> jump to it.  You will need to modify this sequence somewhat...
> 
> Regards,
> 
> John