Firmware update and FPROT

[dastek]

Hi,

I want to be able to update the firmware on my 9sXEQ384.

I have the above process working but if I write to the FPROT register then I have no way to start my firmware update as I immediatly get an access violation when I start the Flash erase cycle.  The manual says this will happen also.  At the moment I leave the FPROT = 0xff and I can do a firmware update.

Now can I write the backdoor key or is there any other way to do this as I would not like to leave the flash un-protected the way I have it at the moment?

I have an enable process that has to be done before I start a firmware update.  Ideally this process would also "modify" FPROT so that I can erase the flash .

Thanks,

Wade

[danielmartynek]

Hi,

P-Flash protection [FPROT] can only be added and not removed. If you need to frequently change the protection, you can use Memory Protection Unit (MPU).

The Backdoor key is a security feature. Normally, the backdoor key value is not stored within the application data and should be received from an external source. But you can use it as well.

MPU and backdoor key examples are attached.

Regards,

Daniel