TM4C1233E6PZ Datasheet, PDF (515/1242 Pages) Texas Instruments – Tiva Microcontroller

Tiva^™ TM4C1233E6PZ Microcontroller
To perform a mass erase of the Flash memory
1. Write the Flash memory write key and the MERASE bit to the FMC register. Depending on the
value of the KEY bit in the BOOTCFG register, the value 0xA442 or 0x71D5 must be written
into the WRKEY field for a Flash memory write to occur.
2. Poll the FMC register until the MERASE bit is cleared or, alternatively, enable the programming
interrupt using the PMASK bit in the FCIM register.
8.2.3.9
32-Word Flash Memory Write Buffer
A 32-word write buffer provides the capability to perform faster write accesses to the Flash memory
by programming 2 32-bit words at a time, allowing 32 words to be programmed in the same time
as 16 would take using the method described above. The data for the buffered write is written to
the Flash Write Buffer (FWBn) registers.
The registers are 32-word aligned with Flash memory, and therefore the register FWB0 corresponds
with the address in FMA where bits [6:0] of FMA are all 0. FWB1 corresponds with the address in
FMA + 0x4 and so on. Only the FWBn registers that have been updated since the previous buffered
Flash memory write operation are written. The Flash Write Buffer Valid (FWBVAL) register shows
which registers have been written since the last buffered Flash memory write operation. This register
contains a bit for each of the 32 FWBn registers, where bit[n] of FWBVAL corresponds to FWBn.
The FWBn register has been updated if the corresponding bit in the FWBVAL register is set.
To program 32 words with a single buffered Flash memory write operation
1. Write the source data to the FWBn registers.
2. Write the target address to the FMA register. This must be a 32-word aligned address (that is,
bits [6:0] in FMA must be 0s).
3. Write the Flash memory write key and the WRBUF bit to the FMC2 register. Depending on the
value of the KEY bit in the BOOTCFG register, the value 0xA442 or 0x71D5 must be written
into the WRKEY field for a Flash memory write to occur.
4. Poll the FMC2 register until the WRBUF bit is cleared or wait for the PMIS interrupt to be signaled.
8.2.3.10
Non-Volatile Register Programming
Note: The Boot Configuration (BOOTCFG) register requires a POR before the committed
changes take effect.
This section discusses how to update the registers shown in Table 8-2 on page 516 that are resident
within the Flash memory itself. These registers exist in a separate space from the main Flash memory
array and are not affected by an ERASE or MASS ERASE operation. With the exception of the Boot
Configuration (BOOTCFG) register, the settings in these registers can be written, their functions
verified, and their values read back before they are committed, at which point they become
non-volatile. If a value in one of these registers has not been committed, a power-on reset restores
the last committed value or the default value if the register has never been committed. Other types
of reset have no effect. Once the register contents are committed, the only way to restore the factory
default values is to perform the sequence described in “Recovering a "Locked"
Microcontroller” on page 198.
To write to a non-volatile register:
■ Bits can only be changed from 1 to 0.
June 12, 2014
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