Hi Richard,
Thanks for being my sounding block, I've now got the RAM code stored
in flash running from RAM at boot.
>>I assume you use GCC.
GNUARM
>>You also need to change the linker script to let
>>the linker know that the code is stored in flash but it will be
running
>>from RAM (just like the initialized variables section).
At the moment my boot app just uses hardcoded addresses to relocate
the RAM code, are you saying I should use the linker script for the
boot app and create a new section similar to the initialised
variables section i.e.
.data : AT (_etext)
{
_data = .;
*(.data)
} > RAM
--- In lpc2000@yahoogroups.com, Richard Duits <yahoo@r...> wrote:
>
> I assume you use GCC. You also need to change the linker script to
let
> the linker know that the code is stored in flash but it will be
running
> from RAM (just like the initialized variables section). When you
copied
> the code to ram, you just load the address of your main routine in
pc.
> If you use interrupts, you may change the MEMMAP register, but this
is
> not needed because the MAM will cache the bytes used by the
interrupt
> vector and it will run just as fast as in RAM. I never did this
myself,
> so I have no example code to share with you, maybe someone else?
>
> Richard Duits
>
>
> tripple_toast wrote:
>
> > Thanks for the reply.
> >
> > So all I need is a section of assembler in boot.s that copies the
> > compiled RAM code from flash to RAM.
> > I've tried the approach of altering the initialised variables
routine
> > without success ( my arm assembler knowledge is not so good ).
> >
> > Once this is copied then how does the RAM code run. Is it a
matter
> > of setting PC to a RAM start address?
> >
> > I'm ensuring that the RAM code is not using any of the ISP RAM
area
> > by loading it into 0x40000200
> >
> > Will I need to set MEMMAP to RAM, I'm not using any IRQ's?
> >
> >
> >
> > --- In lpc2000@yahoogroups.com, Richard Duits <yahoo@r...> wrote:
> > > This depends on the compiler/tools you use. With GNU you can do
> > this in
> > > the linker script and startup.s (similar to initialized
variables).
> > The
> > > Keil compiler has a function attribute that lets you run some
> > functions
> > > from ram. Don't know about other compilers.
> > >
> > > Richard Duits.
> > >
> > >
> > >
> > >
> > > tripple_toast wrote:
> > >
> > > > I have managed to store in a flash sector code that is
compiled to
> > > > run from RAM. At boot I wish to copy this code from flash to
RAM
> > and
> > > > then
> > > > run the code in RAM.
> > > >
> > > > Is this possible using the LPC213x?
> > > >
> > > > What do I need to do in the boot file of the flash code to get
> > the RAM
> > > > code running?
> > > >
> > > > Thanks.
> > > >
> > > >
> > > >
> > > >
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>Message
Re: Flash to RAM
2005-10-07 by tripple_toast