The ROM security feature provides hardware support for securing user software code by preventing unauthorized reading from the internal code when enabled. When using this feature, the processors do not boot-load any external code, executing exclusively from internal ROM. Additionally, the processors are not freely accessible via the JTAG port. Instead, a unique 64-bit key, which must be scanned in through the JTAG or Test Access Port will be assigned to each customer.
The internal ROM is not user programmable. It is factory programmed and requires a minimum order for custom ROM programmed parts. For further details please contact your local sales representative.
I have been programming my 21469 ezboard most for fun, but the result is really very good, so I am thinking maybe I will design a card and put my software on it. The problem is that I cannot afford a custom ROM. And I don´t want anyone to peek into my code.
What I want could be accomplished with a public/private key structure supported by rom and tools for encryption of the load file. Only the rom can decrypt the file since the private key exists only inside the rom. Anyone can encrypt a load file with the public key. By marking the load file with a magic pattern at start, the boot rom will know that the load file is encrypted.