LM3S5G31 Datasheet, PDF (320/1223 Pages) Texas Instruments – Stellaris LM3S5G31 Microcontroller

Internal Memory
7.2.3.6
2. Write the target address to the FMA register. This must be a 32-word aligned address (that is,
bits [6:0] in FMA must be 0s).
3. Write the Flash memory write key and the WRBUF bit (a value of 0xA442.0001) to the FMC2
register.
4. Poll the FMC2 register until the WRBUF bit is cleared or wait for the PMIS interrupt to be signaled.
Non-Volatile Register Programming
Note: The Boot Configuration (BOOTCFG) register requires a POR before the committed
changes take effect.
This section discusses how to update the registers shown in Table 7-2 on page 321 that are resident
within the Flash memory itself. These registers exist in a separate space from the main Flash memory
array and are not affected by an ERASE or MASS ERASE operation. With the exception of the Boot
Configuration (BOOTCFG) register, the settings in these registers can be written, their functions
verified, and their values read back before they are committed, at which point they become
non-volatile. If a value in one of these registers has not been committed, any type of reset restores
the last committed value or the default value if the register has never been committed. Once the
register contents are committed, the only way to restore the factory default values is to perform the
sequence described in “Recovering a "Locked" Microcontroller” on page 178.
To write to a non-volatile register:
■ Bits can only be changed from 1 to 0.
■ For all registers except the BOOTCFG register, write the data to the register address provided
in the register description. For the BOOTCFG register, write the data to the FMD register.
■ The registers can be read to verify their contents. To verify what is to be stored in the BOOTCFG
register, read the FMD register. Reading the BOOTCFG register returns the previously committed
value or the default value if the register has never been committed.
■ The new values are effectively immediately for all registers except BOOTCFG, as the new value
for the register is not stored in the register until it has been committed.
■ Prior to committing the register value, any type of reset restores the last committed value or the
default value if the register has never been committed.
To commit a new value to a non-volatile register:
■ Write the data as described above.
■ Write to the FMA register the value shown in Table 7-2 on page 321.
■ Write the Flash memory write key and set the COMT bit in the FMC register. These values must
be written to the FMC register at the same time.
■ Committing a non-volatile register has the same timing as a write to regular Flash memory,
defined by T_PROG, as shown in Table 25-20 on page 1155. Software can poll the COMT bit in the
FMC register to determine when the operation is complete, or an interrupt can be enabled by
setting the PMASK bit in the FCIM register.
■ When committing the BOOTCFG register, the INVDRIS bit in the FCRIS register is set if a bit
that has already been committed as a 0 is attempted to be committed as a 1.
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July 03, 2014
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