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Programming STM32 Option bytes : When and where ?

Question asked by dumas.jerome on Mar 6, 2013
Latest reply on Mar 18, 2013 by bil.til
Dear All
I'm using IAR EWARM to compile my bootloader and application.
I'm developing on STM32L151 64K version.

My bootloader is located in pages 0-63, sectors 0-3, I would like to protect this area against flash write, just to be sure my bootloader will never been written spuriously.

I understand I have to write the WRP byte of option bytes to enable this protection.
What I do not understand is where and when I should write these option bytes ?

1) Should these option bytes should be included into the hex or bin file ? So I'm sure the protection will be active once the chip burned with the hex or bin file ?
If so, how can I configure IAR to setup these option bytes ?

2) In my bootloader code ? Should I programmatically write the option bytes in my bootloader code ? I tried, but it seems as soon as the option byte is written, the chip resets and then an infinite loop occurs.

3) ?

I agree I'm missing the basics about the options bytes programming, any help would be greatly appreciated !
Thanks
Jerome

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