Posted on May 17, 2011 at 12:19Hi,
Once RDP is enabled :
1) Main Flash memory read access is not allowed except for the user code (when booting from main Flash memory itself with the debug mode not active).
2) Pages 0-3 (for low- and medium-density devices), or pages 0-1 (for high-density devices) are automatically write-protected. The rest of the memory can be programmed by the code executed from the main Flash memory (for IAP, constant storage, etc.), but it is protected against write/erase (but not against mass erase) in debug mode or when booting from the embedded SRAM.
3) All features linked to loading code into and executing code from the embedded SRAM are still active (JTAG/SWD and boot from embedded SRAM) and this can be used to disable the read protection. When the read protection option byte is altered to a memory-unprotect value, a mass erase is performed.
Protecting The First Pages of flash: is a important feature that protects your own IAP ( programming code ) to be erased or to be overwritten even after a PC ( program Counter) Loss or a wrong procedure.
Hope this helps you.
Cheers,
STOne-32.
