stm32mp135f otp can't fuse again

[guansonghuang]

Hi st frends:

  Yestarday I fuse the OTP PKHTH as follow

But today I found  the key I fuse is not the correct one. So I want to re-fuse the OTP ，it seems that can't no fuse again.  is there any way to fuse the OTP this situation?

 

[PatrickF]

HI @guansonghuang 

unfortunately, this is not possible.

on upper OTPs (31 to 95), trying to program a different value will likely make the platform bricked as embedded ECC protection cannot be correct as well (as fused bits cannot be cleared).

On lower OTPs (0 to 31), you could only sets new bits to '1', but once set, a bit cannot be cleared (this is intrinsic to the fuses).

Refer to reference manual

Regards.

[guansonghuang]

hi @PatrickF   by the way, what is the meaning of lock as follow

lock: 1000000

and 

lock: 5000000

 

[PatrickF]

From that page, you could see

 

0x10000000 is "Shadow write sticky lock"

0x50000000 is "Shadow write sticky lock" + "Permanent write lock"

 

Regards.