Posted on October 15, 2002 at 14:48 The Code Temporary Unprotect (CTU) command must be executed from Flash space. But the Block Temporary Unprotect (BTU) can be fed from any memory - external memory, RAM or Flash -.
In order to protect the device against code dumping, the customer need to use the Code Protection command. With this protection activated Flash memory cannot be accessed neither in read nor in write modes from any other memory than the internal Flash. - i.e. programming and erasure fetched from RAM or external memory will not work -
Any illegal read access returns the ST10 op code 0x009B.
Before any Flash modifications the CTU command must be executed to temporarily disable the code protection.
the block protection is used to protect specific banks of flash from erasing 'by mistake' and is not done for piracy protection (because it can be easily deactivated).
The boot code is usually the part of the code protected with this protection.
