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HOW CAN set MM9Z1I638 to safe mode ,i need help,THANKS

I have a question about using MM9Z1I638 to open the safe mode. I read the manual and learned that the FSEC register is used to open the safe mode, but this register does not seem to support direct writing, and needs to be written through FLASH programming. The address segment written is 0xFF_FE0F bytes of P_FLASH block, The minimum sector size supported by

P_FLASH is 512byte. I wrote bytes in accordance with the process of erasing sectors, verifying sectors and writing sectors, but found that every time after erasing sectors, the software would run to an illegal place. After checking, I found that all the information stored in this sector is the add

Battery SensorsRe: HOW CAN set MM9Z1I638 to safe mode ,i need help,THANKS

Hi SHAOWEN

You mean security?

If so, please read the datasheet page 403: 6.14.5 Security for a detailed description.

Re: HOW CAN set MM9Z1I638 to safe mode ,i need help,THANKSI read the description of the security byte in 6.14.5, which says that after the next reset, the value of the address 0xFF_FE0F will be used to initialize the FSEC register. My question now is how to write a value to the address 0XFF_FE0F. I used the method described above to erase the sector before, and the value was detected by single-step debugging. The value of the address 0XFF_FE0F was changed, but then the software jumped to an illegal position through the debugger data analysis. So I would like to ask what is the normal process of writing this address. Thank you