Re: [avr-chat] How can I individualise specific CPUs?

[Bill Gatliff]

Graham Davies wrote:
> What Juergen means, I think, is that when you change the application 
> program in a device, you either have a bootloader or you use a 
> hardware programming mechanism such as ISP, JTAG or (heaven forbid) 
> High-Voltage.  With a bootloader, you have a lot of freedom about what 
> gets erased and what gets preserved, but with a hardware programming 
> mechanism you generally start with a chip erase which wipes the entire 
> Flash.  What Juergen wanted, if I've been following correctly, is for 
> a hardware re-program to leave the contents of the boot loader section 
> alone so that he could squirrel away his "individualizations" there.

Such "personalizations" might include end-user-supplied data or options, 
calibration values that are learned in-situ, etc.  Stuff that can't be 
known prior to reprogramming the device, unless you read it out of the 
device before wiping it.

So yea, it would be nice to have tighter control over what gets erased 
during a firmware update...


b.g.

--
Bill Gatliff
address@hidden