Lpc2000

Hello,

I would like to copy FIQ code from flash to ram a startup and then run
FIQ code from RAM(better response). How can i do that in C.

/Pero

At 04:34 AM 3/16/04 +0100, you wrote:
>I would like to copy FIQ code from flash to ram a startup and then run
>FIQ code from RAM(better response). How can i do that in C.

What compiler?

Also how much better response are you expecting?

Robert


" 'Freedom' has no meaning of itself.  There are always restrictions,
be they legal, genetic, or physical.  If you don't believe me, try to
chew a radio signal. "

                         Kelvin Throop, III

--- In lpc2000@yahoogroups.com, Peter Kuhar <peter.kuhar@g...> wrote:
> Hello,
> 
> I would like to copy FIQ code from flash to ram a startup and then 
run
> FIQ code from RAM(better response). How can i do that in C.
> 
> /Pero

On an LPC210x with MAM enabled, it isn't that obvious that you will 
get a huge performance kick from running an FIQ from RAM. This might 
be a case where assembler is the way to go to tweak the code )if it is 
small.

Anyway, back to your question....The way you do this is very compiler 
dependent. You will need to link/locate the code to use RAM adresses. 
Typically, the copy-to-ram is done by the assembler start-up code that 
executes before main. The concept involved is very similar to the 
initilaisation of your data segment (ie. the segment's imnitialisation 
data gets coipied from flash into RAM). Depending on your compiler, 
this might be as easy as setting a pragma or such or might need some 
manual effort.

-- Charles

I'm trying to use ADS1.2. The FIQ code is very short, so i would like
to gain the time, needed for MAM to load his buffers.

I was trying to do it like this:(it works for IRQ(T0) but not for FIQ
(SPI))

unsigned long t0_irq_ram[400/4];
unsigned long spi_irq_ram[600/4];

__irq void spi_irq()
{       
        //bla bla bla
}
__irq void t0_irq()
{
      //bla bla bla
}

        int i;
        for(i=0;i<100;i++){
                t0_irq_ram[i]=((unsigned int *)t0_irq)[i];
        }
        for(i=0;i<(600>>2);i++){
                spi_irq_ram[i]=((unsigned int *)spi_irq)[i];
        }


Vectors         LDR     PC, Reset_Addr
                LDR     PC, Undef_Addr
                LDR     PC, SWI_Addr
                LDR     PC, PAbt_Addr
                LDR     PC, DAbt_Addr
                NOP                            ; Reserved Vector 
                LDR pc,[pc,#-0xFF0]              ;irq
                LDR     PC,=spi_irq_ram          ;fiq
        
/Pero

---
Tuesday, March 16, 2004, 7:48:03 AM, si napisal:

> --- In lpc2000@yahoogroups.com, Peter Kuhar <peter.kuhar@g...> wrote:
>> Hello,
>> 
>> I would like to copy FIQ code from flash to ram a startup and then 
> run
>> FIQ code from RAM(better response). How can i do that in C.
>> 
>> /Pero

> On an LPC210x with MAM enabled, it isn't that obvious that you will 
> get a huge performance kick from running an FIQ from RAM. This might
> be a case where assembler is the way to go to tweak the code )if it is
> small.

> Anyway, back to your question....The way you do this is very compiler
> dependent. You will need to link/locate the code to use RAM adresses.
> Typically, the copy-to-ram is done by the assembler start-up code that
> executes before main. The concept involved is very similar to the 
> initilaisation of your data segment (ie. the segment's imnitialisation
> data gets coipied from flash into RAM). Depending on your compiler, 
> this might be as easy as setting a pragma or such or might need some
> manual effort.

> -- Charles







 
> Yahoo! Groups Links

At 11:40 AM 3/16/04 +0100, you wrote:
>I'm trying to use ADS1.2. The FIQ code is very short, so i would like
>to gain the time, needed for MAM to load his buffers.
>
>I was trying to do it like this:(it works for IRQ(T0) but not for FIQ
>(SPI))

Since it works for the IRQ (and it seems important to you) you must have an 
idea of how much this improves the response time.  What are you seeing?

Robert

" 'Freedom' has no meaning of itself.  There are always restrictions,
be they legal, genetic, or physical.  If you don't believe me, try to
chew a radio signal. "

                         Kelvin Throop, III