LM3S6950 Datasheet, PDF (136/524 Pages) List of Unclassifed Manufacturers – Microcontroller

Internal Memory
8.3.2
Nonvolatile 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
in the FMC register to activate a write operation. For the USER_DBG register, the data to be written
must be loaded into the FMD register before it is "committed". All other registers are R/W and can
have their operation tried before committing them to nonvolatile memory.
Important: These register can only have bits changed from 1 to 0 by the user and there is no
mechanism for the user to erase them back to a 1 value.
In addition, the USER_REG0, USER_REG1, and USER_DBG use bit 31 (NOTWRITTEN) of their
respective registers to indicate that they are available for user write. These three registers can only
be written once whereas the flash protection registers may be written multiple times. Table
8-2 on page 136 provides the FMA address required for commitment of each of the registers and
the source of the data to be written when the COMT bit of the FMC register is written with a value of
0xA442.0008. After writing the COMT bit, the user may poll the FMC register to wait for the commit
operation to complete.
Table 8-2. Flash Resident Registers^a
Register to be Committed FMA Value Data Source
FMPRE0
0x0000.0000 FMPRE0
FMPRE1
0x0000.0002 FMPRE1
FMPRE2
0x0000.0004 FMPRE2
FMPRE3
0x0000.0008 FMPRE3
FMPPE0
0x0000.0001 FMPPE0
FMPPE1
0x0000.0003 FMPPE1
FMPPE2
0x0000.0005 FMPPE2
FMPPE3
0x0000.0007 FMPPE3
USER_REG0
0x8000.0000 USER_REG0
USER_REG1
0x8000.0001 USER_REG1
USER_DBG
0x7510.0000 FMD
a. Which FMPREn and FMPPEn registers are available depend on the flash size of your particular Stellaris^® device.
8.4 Register Map
Table 8-3 on page 136 lists the Flash memory and control registers. The offset listed is a hexadecimal
increment to the register's address. The FMA, FMD, FMC, FCRIS, FCIM, and FCMISC registers
are relative to the Flash control base address of 0x400F.D000. The FMPREn, FMPPEn, USECRL,
USER_DBG, and USER_REGn registers are relative to the System Control base address of
0x400F.E000.
Note: A BV in the Reset column indicates the reset is a Build Value and part-specific. See the
page number referenced for the reset value description.
Table 8-3. Internal Memory Register Map
Offset Name
Type
Reset
Flash Control Offset
Description
See
page
136
June 14, 2007
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