I have a bootloader that resides from 0x000 to 0x2FF. It uploads new =
user code
that has been offset to 0x300.

I want to be able to protect the bootloader code from being read and =
also ensure the
bootloader will only operate when is reads the correct values from IDLOC =
in config memory
(I assume this is done sing tblerd ?).

Basically, I am looking for a method of ensuring that only our code will =
run on our hardware
and that our code will not run in other hardware.

So far I have considered encrypting the hex file and appending a key =
value to the file.
Our Windows uploader program then loads the encrypted file, decodes it =
and programs the key value to=20
rom as part of the upload process.

The code then checks an internal value with the programmed key value and =
also checks the IDLOC
if both are valid, it runs.
The bootloader only runs if the IDLOC is correct.

My thinking is that if the bootloader cannot be read and copied, then it =
would be specific to each ouf
our hardware devices.

(PS. I am looking for a method that does not require addition of =
external hardware such as Dallas serial
ID chip etc as I want this to be retrofitted to existing hardware.

Thanks for any ideas on code protection. (Maybe there is a much simpler =
way)

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads