LM3S3768 Luminary Micro, Inc, LM3S3768 Datasheet - Page 163

• Manufacturer Part Number: LM3S3768
• Description: Lm3s3768 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

8.3.1.2
8.3.1.3
8.3.2
June 02, 2008
4.
To perform an erase of a 1-KB page
1.
2.
3.
To perform a mass erase of the flash
1.
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:
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 163
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
Register to be Committed
FMPRE0
FMPRE1
FMPRE2
FMPRE3
FMPPE0
FMPPE1
FMPPE2
FMPPE3
USER_REG0
USER_REG1
Poll the FMC register until the WRITE bit is cleared.
Write the page address to the FMA register.
Write the flash write key and the ERASE bit (a value of 0xA442.0002) to the FMC register.
Poll the FMC register until the ERASE bit is cleared.
Write the flash write key and the MERASE bit (a value of 0xA442.0004) to the FMC register.
Poll the FMC register until the MERASE bit is cleared.
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 59. 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
FMA Value
FMPRE0
FMPRE1
FMPRE2
FMPRE3
FMPPE0
FMPPE1
FMPPE2
FMPPE3
USER_REG0
USER_REG1
Data Source
Preliminary
a
LM3S3768 Microcontroller
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