[En-Nut-Discussion] Fwd: RE: Reprogramming

[Ulrich Prinz]

Hi!

Very difficult to answer this question.
What exact AVR CPU do you use? Not all of them have a bootloader option.
The ones without you have to place a bootloader code inside your self. 
ATMEL has some application notes for that. They place the bootloader 
into top of the flash.
> 
> 
> My customer has requested a method for upgrading the software while
> the unit is in service.
> 
> Seems to me I have two options:
> 
> 1. Write a resident loader and the needed functionality to receive
> the new software, and write it (somehow) into flash memory.
The bootloaders only us a small portion of the flash. So it is possible 
for using serial, USB or CAN as a flash connection.
> 
> 2. Used BOOTP/TFTP and the available boot loader.
This might get hard to do as you need a downsized network stack with 
these protocols running.

Best regards,
Ulrich