LM3S1637 Luminary Micro, Inc, LM3S1637 Datasheet - Page 145

• Manufacturer Part Number: LM3S1637
• Description: Lm3s1637 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

8.3.2
8.4
July 25, 2008
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:
In addition, the USER_REG0, USER_REG1, and USER_DBG use bit 31 (NW) 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 145
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. Which FMPREn and FMPPEn registers are available depend on the flash size of your particular Stellaris
Register Map
Table 8-3 on page 146 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.
Register to be Committed
FMPRE0
FMPRE1
FMPRE2
FMPRE3
FMPPE0
FMPPE1
FMPPE2
FMPPE3
USER_REG0
USER_REG1
USER_DBG
These registers can only have bits changed from 1 to 0 by user programming, but can
be restored to their factory default values by performing the sequence described in the
section called “Recovering a "Locked" Device” on page 55. The mass erase of the main
flash array caused by the sequence is performed prior to restoring these registers.
0x0000.0000
0x0000.0002
0x0000.0004
0x0000.0008
0x0000.0001
0x0000.0003
0x0000.0005
0x0000.0007
0x8000.0000
0x8000.0001
0x7510.0000
FMA Value
FMPRE0
FMPRE1
FMPRE2
FMPRE3
FMPPE0
FMPPE1
FMPPE2
FMPPE3
USER_REG0
USER_REG1
FMD
Data Source
Preliminary
a
LM3S1637 Microcontroller
®
device.
145