How (not) to Secure my Microcontroller

There are several reports in the Freescale forums around having ‘secured’ the Freedom board. But what does ‘securing’ a board mean? And what does it mean if I get that ‘Device is Secure’ dialog?

Device is Secure. Erase to unsecure?

Device is Secure. Erase to unsecure?

There are different levels of protection you can find in many embedded microprocessors, and the terms might vary from vendor to vendor:

  1. Protect
  2. Secure
  3. Disable Mass Erase

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Defining Variables at Absolute Addresses with gcc

Many compilers offer a way to allocate a variable at an absolute address. For example for the Freescale S08 compiler, I can place my variable at a given address:

unsigned char buf[128]@0x2000;

This is very useful (and needed) e.g. if the hardware (like USB) needs a buffer at given address. The advantage of the above (non-ANSI and thus not portable) syntax is that I can define a variable at an absolute address, without the need to allocate it in the linker.

I wanted to do something similar with gcc for Kinetis/ARM, and searched many forums on the internet. Obviously, I’m not alone with this question. The solution I have found comes close to what I use e.g. for the S08 compiler.

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