XMC4500 - UCB (re)program cycles

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User9239
Level 1
Level 1
Hello

in the datasheet and reference manual is written, that only four times it is possible to reprogram the UC-pages (UCB:user configuration block).

What happens if it will be repogrammed more than four times?
For me it seems, that the controller will be destroyed. I am not able to connect to the ASC BSL anymore. Also the programm in the flash is not running anymore.

Thanks!
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6 Replies
Travis
Employee
Employee
First solution authored Welcome! 500 replies posted
Did you erase and reprogram the UCB (eg. changing the password) for more than 4 times?
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User9239
Level 1
Level 1
Yes. I am developing an asc bsl. During developing I erased and reprogrammed UCB more than four times.
I did not realize the maximum limit of four.

Is the controller now broken or is it possible to make it alive again?
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Travis
Employee
Employee
First solution authored Welcome! 500 replies posted
We have a limit of 4 for UCB erase/reprogram. In general it might be able to go for more than 4 times (or even more than 10) before something happens.
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User9239
Level 1
Level 1
... before something happens


What does this exactly mean?
Is the controller broken forever, if the maximum limit of 4-10 UCB erase/program cycles is exceeded?

Why is there such a low limit? Is it becaus of memory chip size/costs ?
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Not applicable
Hi olnol,

When the UCB is erase more than 4 times, the data on the UCB could be corrupted.
Hence, during the startup, the startup firmware is unable to read data from UCB which content protection configuration.
As stated in the Reference Manual, "Over-cycling the UCBs can also lead to an unusable device"

olnol wrote:

Why is there such a low limit? Is it becaus of memory chip size/costs ?


UCBs are logical sectors, and as such the allowed number of program/erase cycles are limited.
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AndreasG
Employee
Employee
10 replies posted 5 replies posted Welcome!
With repsect to the failure of the device, slightly violating the number of program/erase cycles usually just leads to long term reliability issues with respect to the data retention no longer reaching its specified values.
Doing so under desk/lab conditions while developing/debugging software should usually not be an issue, but yes, eventually the device may be rendered broken if sectors, especially the UCBs, are cycled too often.

I assume you are using the UCBs to configure the flash protection and/or BMI configuration? Could it also be that you may have written a bad configuration value?!
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