How can one write data into internal FLASH on TM4C129 and then protect that data from inadvertent modification?

Randy Bulloch said:

I need to modify the block of FLASH with new data at a later time.

While your question provides "necessary" data - it falls short of providing, "sufficient" data.

Describing your, "When, where, how" (at a later time) you intend to "modify" that Flash block may add that sufficiency...

 

Hello Randy

The first thing to note is how does the micro distinguish between inadvertent and intended modification? That shall set the course for the discussion.

Regards
Amit

Presumably by unprotecting. Typically in EE or FRAM non-volatile storage there is a sequence to enable writing and another to write protect the contents. In addition there is often an external write protect pin that effectively disables the write enable sequence.

My question would be what is the range of inadvertent writes you want to protect against, rogue program, noise events, power down while write, unauthorized access etc...

Robert

Hi Amit,

Pardon my attempt to be brief resulting in too  little info.

The idea was for an operator to indicate to the program (a physical switch or software command) the only time to change the critical data and to provide some manner of additional protection from "bad" software corrupting the data by making the critical data READ_ONLY, i.e. using FlashProtectSet() API.

The idea was to protect this "critical" data from corruption from software with bugs overwriting the data.  The realization now is that this data, no matter how critical, is no more important and no more vulnerable than the program itself, both are in flash memory.  Thus the initial idea that making this block of data READ_ONLY using the FlashProtectSet() API to "protect" the data is a trivial improvement (if any) in protecting this data and is not going to be used.  It is considered sufficient that the data is in Flash memory and requires a very specific and unlikely Flash write sequence to corrupt it.

Thanks for your time,

Randy

Hello Randy

Exactly. Some level of security needs to be established. One of the ways we have been thinking is to have the flash boot loader at customer installation validate the application image authenticity. Thus the first place of snooping the bus would reveal only encrypted data. The task here would be to keep the decryption key protected in the TM4C.

Regards
Amit