TM4C123GH6PM Datasheet, PDF (533/1409 Pages) Texas Instruments – Tiva Microcontroller

Tiva^™ TM4C123GH6PM Microcontroller
■ 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, a power-on 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 8-2 on page 533.
■ 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_PROG64, as shown in Table 24-27 on page 1384. 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.
■ Once the value has been committed, a power-on reset has no effect on the register contents.
■ Changes to the BOOTCFG register are effective after the next power-on reset.
■ Once the NW bit has been changed to 0 and committed, further changes to the BOOTCFG register
are not allowed.
Important: After being committed, these registers can only be restored to their factory default values
by performing the sequence described in “Recovering a "Locked"
Microcontroller” on page 205. The mass erase of the main Flash memory array caused
by the sequence is performed prior to restoring these registers.
Table 8-2. User-Programmable Flash Memory Resident Registers
Register to be Committed
FMPRE0
FMPRE1
FMPRE2
FMPRE3
FMPPE0
FMPPE1
FMPPE2
FMPPE3
FMA Value
0x0000.0000
0x0000.0002
0x0000.0004
0x0000.0006
0x0000.0001
0x0000.0003
0x0000.0005
0x0000.0007
Data Source
FMPRE0
FMPRE1
FMPRE2
FMPRE3
FMPPE0
FMPPE1
FMPPE2
FMPPE3
June 12, 2014
533
Texas Instruments-Production Data