LM3S3748 Datasheet, PDF (163/753 Pages) List of Unclassifed Manufacturers – Microcontroller

LM3S3748 Microcontroller
8.3.1.2
8.3.1.3
8.3.2
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.
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.
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 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.
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^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
April 08, 2008
163
Preliminary