Internal Memory

FMPPEnFMPREnProtection

01 Read-onlyprotection. Theblockmaybereadorexecutedbutmaynotbewrittenorerased. Thismode is used to lock the block from further modification while allowing any read or execute access.

AnaccessthatattemptstoprogramoreraseaPE-protectedblockisprohibited. Acontrollerinterrupt maybeoptionallygenerated(bysettingthe AMASK bitinthe FIM register)toalertsoftwaredevelopers of poorly behaving software during the development and debug phases.

An access that attempts to read an RE-protected block is prohibited. Such accesses return data filled with all 0s. A controller interrupt may be optionally generated to alert software developers of poorly behaving software during the development and debug phases.

The factory settings for the FMPREn and FMPPEn registers are a value of 1 for all implemented banks. This implements a policy of open access and programmability. The register bits may be changed by writing the specific register bit. The changes are not permanent until the register is committed (saved), at which point the bit change is permanent. If a bit is changed from a 1 to a 0 and not committed, it may be restored by executing a power-on reset sequence. Details on programming these bits are discussed in “Nonvolatile Register Programming” on page 154.

8.3Flash Memory Initialization and Configuration

8.3.1Flash Programming

The Stellaris® devices provide a user-friendly interface for flash programming. All erase/program operations are handled via three registers: FMA, FMD, and FMC.

8.3.1.1To program a 32-bit word

1.Write source data to the FMD register.

2.Write the target address to the FMA register.

3.Write the flash write key and the WRITE bit (a value of 0xA442.0001) to the FMC register.

4.Poll the FMC register until the WRITE bit is cleared.

8.3.1.2To perform an erase of a 1-KB page

1.Write the page address to the FMA register.

2.Write the flash write key and the ERASE bit (a value of 0xA442.0002) to the FMC register.

3.Poll the FMC register until the ERASE bit is cleared.

8.3.1.3To perform a mass erase of the flash

1.Write the flash write key and the MERASE bit (a value of 0xA442.0004) to the FMC register.

2.Poll the FMC register until the MERASE bit is cleared.

8.3.2Nonvolatile Register Programming

This section discusses how to update registers that are resident within the flash memory itself. These registers exist in a separate space from the main flash array and are not affected by an ERASE or MASS ERASE operation. These nonvolatile registers are updated by using the COMT bit

Preliminary