Option bytes config issue

[Rakesh936]

Hi,

I am trying lock a portion of Flash memory using WRP(Write Protection). when I am configuring the Option bytes for WRP. I am using STM32L443VC MCU and I have multiple questions:

1. Which area to select WRPAreaA or WRPAreaB for page 0 to page 11 because there is no division of area given?

2. I am trying to lock from page 0 to page 11 in the flash memory but I am seeing different values even after OBL launch:

example: WRPStartOffset = 0x80  (Expected: 0x00)

                WRPEndoffset = 0x0B (Expected: 0x0B)

This is because in the reference manual I see FLASH_WRP1AR reset value is 0xFFXX FFXX and in the register value is 0xFF00 FFFF. If I use Register value got 0xFF0B FF80 instead of 0xFF0B FF00. if I assume 0xFF00 FF00 i am getting 0xFF0BFF00. Even I tried for different page offset still I am seeing Startoffset value different. Please check the attached snapshots for your reference.

3. I am using segger jlink to flash the code and Please let me know how to flash using jlink for option bytes.

Please find the attached documents for your reference.

[STOne-32]

Dear @Rakesh936 ,

Thanks for the follow-up . regarding Jflash tool from Segger , I believe the key word in our manual is “software” mass erase, it  is not possible if one page is Write protected . That means the embedded firmware  executed from Flash or RAM by CPU can not erase it self or do a mass erase. However with Jflash or Programmer they take the control over JTAG/SWD to the flash and have the ability to have back the device to a virgin ( out of factory) with A mass erase .   In that case, we need to go to further level of protection and disabling the Debug I/F once your end product is released to market .

Hope it helps you,

STOne-32

[Rakesh936]

Hi @STOne-32,

Thanks for the reply.

I understood the issue.

Thank you 

@Rakesh936