FMA values for writing FMPPE8 and above (protection on TivaC Snowflake with OpenOCD)

Hello Pavel,

Is the issue only for FMPPE registers, or is it there for FMPRE registers also, i.e the values are lost after power cycle?

Regards

Amit

From the debug log I got from karlp, it seems the issue is only with FMPPE registers >= 8, those before work as expected. I haven't tried implementing FMPRE at all as nobody has requested it so far, so haven't done any tests, and since I have no Snowflake hardware, I can't do it myself. 

I hope somebody who is interested in Tiva C support can give me a hand here and test the patch to get more datapoints. Also, securing manually by writes to FMPPE8 and above might be interesting to try.

For the reference, the log (human-readable, doesn't require any openocd knowledge) is here:  http://paste.fedoraproject.org/129122/09175814/ . You can see how FMPPE7 works and FMPPE8 write is ignored apparently.

Hi, 

I know this is an old issue, but I am faced with the same. 

I have a TM4C129 that I am trying to protect. 

Protecting FMPRE0-7 works as expected, but FMPRE8-15 does not retain their values thrugh POR.

Is there any special handling required for FMPRE8-15?

The code I am using is this:

    HWREG(FLASH_FMPRE8) = 0;
        for(ui32Temp = 0x10; ui32Temp <= 0x10; ui32Temp += 2) //Protect all FMPRE registers. Datasheet p.597
    {
        //
        // Tell the flash controller to write the flash protection register.
        //
        HWREG(FLASH_FMA) = ui32Temp;
        HWREG(FLASH_FMC) = FLASH_FMC_WRKEY | FLASH_FMC_COMT;

        //
        // Wait until the write has completed.
        //
        while(HWREG(FLASH_FMC) & FLASH_FMC_COMT)
        {
        }
    }

Best regards,

Mads