Datasheet

the EEPROM Software Reset (SREEPROM) register, wait until WORKING bit in the EEPROM Done
Status (EEDONE) register is clear, and then enable the debug mass erase by setting the ME bit in
the EEPROM Debug Mass Erase (EEDBGME) register.
Error During Programming
Operations such as data-write, password set, protection set, and copy buffer erase may perform
multiple operations. For example, a normal write performs two underlying writes: the control word
write and the data write. If the control word writes but the data fails (for example, due to a voltage
drop), the overall write fails with indication provided in the EEDONE register. Failure and the corrective
action is broken down by the type of operation:
■ If a normal write fails such that the control word is written but the data fails to write, the safe
course of action is to retry the operation once the system is otherwise stable, for example, when
the voltage is stabilized. After the retry, the control word and write data are advanced to the next
location.
■ If a password or protection write fails, the safe course of action is to retry the operation once the
system is otherwise stable. In the event that multi-word passwords may be written outside of a
manufacturing or bring-up mode, care must be taken to ensure all words are written in immediate
succession. If not, then partial password unlock would need to be supported to recover.
■ If the word write requires the block to be written to the copy buffer, then it is possible to fail or
lose power during the subsequent operations. A control word mechanism is used to track what
step the EEPROM was in if a failure occurs. If not completed, the EESUPP register indicates
the partial completion.
After a reset and prior to writing any data to the EEPROM, software must read the EESUPP register
and check for the presence of any error condition which may indicate that a write or erase was in
progress when the system was reset due to a voltage drop. If either the PRETRY or ERETRY bits are
set, the peripheral should be reset by setting and then clearing the R0 bit in the EEPROM Software
Reset (SREEPROM) register and waiting for the WORKING bit in the EEDONE register to clear
before again checking the EESUPP register for error indicators. This procedure should allow the
EEPROM to recover from the write or erase error. In very isolated cases, the EESUPP register may
continue to register an error after this operation, in which case the reset should be repeated. After
recovery, the application should rewrite the data which was being programmed when the initial
failure occurred.
Endurance
Endurance is per meta-block which is 8 blocks. Endurance is measured in two ways:
1. To the application, it is the number of writes that can be performed.
2. To the microcontroller, it is the number of erases that can be performed on the meta-block.
Because of the second measure, the number of writes depends on how the writes are performed.
For example:
■ One word can be written more than 500K times, but, these writes impact the meta-block that the
word is within. As a result, writing one word 500K times, then trying to write a nearby word 500K
times is not assured to work. To ensure success, the words should be written more in parallel.
■ All words can be written in a sweep with a total of more than 500K sweeps which updates all
words more than 500K times.
649December 13, 2013
Texas Instruments-Advance Information
Tiva
™
TM4C129XNCZAD Microcontroller