MSPM0C1104: Memory map location (to prevent self-write of flash from overwriting program memory)

Hi Seth,

First, to protect a range of FLASH memory from rouge self erase/programming by the application, consider using the Dynamic Write Protect method described in section 5.4 in the TRM. It will allow the application to write protect one or more sectors from accidental erase/programming operations by the CPU.  When the application needs to modify the write protected sectors, disable write protect (modify R/W bits in CMDWEPROTA register) and modify the sectors. At the end of the programming/erase cycle the write protection is automatically re-enabled. This is how it is used in EEPROM emulation.

BTW, There is an example of this in the MSPM0 SDK.  You can find it in the folder:
C:\ti\mspm0_sdk_2_04_00_06\examples\nortos\LP_MSPM0C1104\driverlib\flashctl_dynamic_memory_protection


Next, to protect the sector from external programming/erase (XDS100), locate your sector(s) that you want to preserve as the last sectors in FLASH. For example, in the mspm0c1104.cmd linker script file, FLASH is defined at address = 0x00000000 with length = 0x00004000 and we want to protect the last sector in FLASH memory.  So borrow one sector from the main FLASH memory region and call it EEPROM and locate it at 0x00003C00 and length = 0x00000400.  BTW, 1 sector size is 0x00000400. Since you will be modifying the linker file,  the EEPROM must be assigned to a "memory section" so create one and name it .calib (calibration) for example.  Now this symbol can be used by the compiler/linker to represent the start address of the EEPROM memory.  See below how to make the changes.

Then, you will want to set the XDS110 debugger Erase configuration to limit the programmer to erase only the area of FLASH from 0x00000000 to 0x00003C00 as seen here, leaving 0x00003C00 through 0x00004000 untouched.

Last, in your code you can access this memory section by declaring your variable as follows and passing the address of this variable, cast as an uint32_t to the DL_FlashCTL functions.

/*
 * Assign the eepromCalibrationTable to the memory section ".calibration"
 * that was created in the linker .cmd file.
 */
__attribute__((section(".calibration")))
uint32_t eepromCalibrationTable;

int main(void)
{
    SYSCFG_DL_init();
    ...
    ...
    ...
        /*
         * Ensure proper flash command execution by clearing the STATCMD
         * register before executing a flash operation
         */
        DL_FlashCTL_executeClearStatus(FLASHCTL);
        DL_FlashCTL_unprotectSector(
            FLASHCTL, (uint32_t) &eepromCalibrationTable, DL_FLASHCTL_REGION_SELECT_MAIN);

        /* Program to flash in main memory */
        gCmdStatus = DL_FlashCTL_programMemoryFromRAM32(
            FLASHCTL, (uint32_t)&eepromCalibrationTable, &gData32);
            ...
            ...

Example project attached.

flash_dynamic_memory_protection_modifed_linker_MSPM0C1104.zip