It's pretty clear the system requirements haven't been considered adequately. For code security, there's that encryption array. Maxim/Dallas has some "secure" mircos that have enhanced security features. They also have some really fast (1x) parts as opposed to various 6x or 4x parts.

So far, there's been no explanation of why the simple BRG based on the 11.0592 MHz crystal is desirable, as opposed, say, to 19.6608 or 24.576.

There's been a really silly explanation of why a large address space is desirable. Surely that's not the driving factor.

Maybe the O/P has realized that and is actually thinking about his requirements.

We should never lose sight of the fact that requirements are things without which the system will fail. Nothing that's not required should be included in the design criteria.

RE