LM3S1620 Datasheet, PDF (135/485 Pages) List of Unclassifed Manufacturers – Microcontroller

LM3S1620 Microcontroller
Table 8-1. Flash Protection Policy Combinations
FMPPEn FMPREn Protection
0
0 Execute-only protection. The block may only be executed and may not be written or erased. This mode
is used to protect code.
1
0 The block may be written, erased or executed, but not read. This combination is unlikely to be used.
0
1 Read-only protection. The block may be read or executed but may not be written or erased. This mode
is used to lock the block from further modification while allowing any read or execute access.
1
1 No protection. The block may be written, erased, executed or read.
An access that attempts to program or erase a PE-protected block is prohibited. A controller interrupt
may be optionally generated (by setting the AMASK bit in the FIM register) to alert software developers
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 136.
8.3 Flash Memory Initialization and Configuration
8.3.1
8.3.1.1
Flash 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.
To 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.
8.3.1.2
4. Poll the FMC register until the WRITE bit is cleared.
To 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.
8.3.1.3
3. Poll the FMC register until the ERASE bit is cleared.
To 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.
September 02, 2007
135
Preliminary