Re: [avr-gcc-list] memory layout for bootloader

[Parthasaradhi Nayani]

Hello,

if you want to place other functions in the bootloader
memory add the attribute to these functions as well.

Ideally one must set the address of .text to boot
address, as bootloader is a completely independent
program. I tested by putting the .text in the
bootloader section and it worked fine.

 > Or are there some disadvantages in this way?

I found one disadvantage or rather I am looking for a
solution.

If one creates a complete program including the main
function and put .text in the bootloader memory, the
startup code, the interrupt vector table and ofcourse
the cleanup code are also added to the binary/hex
image. If one is not using any interrupts in the
bootloader, why waste this memory? similarly why
occupy some more memory for cleanup as this may never
be used?
I found this to be a disadvantage.

How does one avoid putting interrupt table and cleanup
code in the bootloader section? (this is what I am
looking for)
 
> I guess i use 0x1E000, as 0xF000 seems to be based
> on 16 bits
> per address, is that correct?

The data sheets talk about word address so you need to
get the byte address by shifting the bootloader
address , mentioned in the docs, left by 1

> 
> I assume that the ATMega128 can execute program in
> all its 128kB,
> is that correct?

Yes.

> Can i really DISABLE SPI programming by fuse bit
> SPIEN?

Never tired this.

Regards
Nayani P




                
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