Hi,

After some customers accidentally activated the protection, and they had to buy new devices, ST and Raisonance decided that by default this feature would be disabled.

Below is the purposefully complex procedure to enable it again. Use it at your own risk, and keep in mind that this protection cannot be removed, even if you send the chip to ST or Raisonance. After the FMP_W bit is set, the flash and option bytes can _never_ be programmed or erased again.

Make a robust validation of the process on a few devices before starting mass production in these conditions.

Best Regards,

Vincent

Here is the procedure to enable writing of this bit:

1. Make a backup copy of this file:
\bin\ST72ICC_ProductInfo.txt

2. Edit the file above in a text editor, search for "[LITE0]"

3. in the "[LITE0]" section, you will see some parameters containing the default option bytes and a mask:
DefOptBytes_Byte0=0xF0
DefOptBytes_Byte1=0xEF
MaskOptBytes_Byte0=0xF1
MaskOptBytes_Byte1=0x20

The "DefOptBytes" parameters describe, for this device, the value written in the option bytes when you "Erase" them.
The "MaskOptBytes" parameters describe which bits must always remain as in the default value. (reserved or dangerous bits)
To enable the setting of the write protection on the Lite0x devices, you must change the mask to this value:

MaskOptBytes_Byte0=0xF0

4. Restart the software and now you should be able to set the write protection.

5. After you have finished the batch, restore the original productinfo file, to avoid accidentaly setting the protection while developing in the future.