I know some Freescale processors allow you to lock the Flash memory using a security code so that it can't be read. You can then use this code to unlock the Flash so that it can be read again. I think that I am confusing these processors with the DSP's Flash lock. From the DSP56800E Targeting Manual, you can set the Flash memory to be locked, thereby inhibiting access to it. You can also unlock it, but in doing so, it erases the Flash.
From the Targeting Manual:
The Flash Unlock command disables the Flash security. This results in all the Flash
memory being erased.
NOTE The Flash Lock and Flash Unlock commands can only be enabled if the
debugger session is not running. To use the Flash Lock or Flash Unlock command:
1. Kill any open debugger sessions.
2. Select a DSP56800E project with a Flash target.
NOTE A Flash target is a target using an initialization file containing Flash
commands.
3. Select a Flash target.
4. Select either Debug > 56800E > Flash Lock or Debug > 56800E > Flash Unlock
command.
I apologize for the confusion.
---Tom