Option bytes - temporary memory unprotection(TMU)

[Ian_L]

Hello everyone.
I am in trouble with the datasheet of STM8AF5288.
There are only brief descriptions about TMU in the datasheet.

What is the difference between TMU and ROP?
How to use TMU?
I can't find any documentation.
Does anyone have more detailed information?
Thank you.

 

 

[AA1]

This is explained in datasheet section 5.4.4 pages 16 and 17.

The read-out protection (ROP) prevents reading and writing Flash program memory, data memory
and option bytes via the debug module and SWIM interface. The ROP circuit may provide a temporary access for debugging or failure analysis. The temporary read access is protected by a user defined, 8-byte keyword stored in the option byte area. This keyword must be entered via the SWIM interface to temporarily unlock the device. If desired, the temporary unlock mechanism can be permanently disabled by the user through OPT6/NOPT6 option bytes.

 

This means that when ROP is active it can be temporarily disable if TMU is enable in OPT6, by providing a 8-byte key. So TMU is a way to temporarily disable ROP for debugging or failure analysis.

 

[Ian_L]

Thanks for your reply!

Is there any specific way to enter the keyword?
I haven't found a way to enter the keyword by STVD or STVP yet.

[AA1]

I never worked with this MCU but datasheet says: This keyword must be entered via the SWIM interface. STVD or STVP should allow to enter this keyword.

Did you try to access memory with ROP and TMU enable?