Download User`s Manual EEPROM Emulation Library EEL

EEPROM Emulation Library
6.3.6
Library behaviour after operation interruption
Library operation might be suddenly interrupted e.g. by a power fail.
Depending on the interrupted operation (E.g. Flash erase, write ....) the
behaviour of the library on the next start-up might differ:
6.3.7

Library was idle or at the end of a operation:
Normal library start-up

Flash block erase or Flash block header operation was interrupted:
Eventually it is necessary to fix a block status (e.g. block activation or
block erase was interrupted). In this case additionally Flash write
operations might take some more time and so, slightly enlarge the time
until the driver leaves the state EEL_OPERATION_STARTUP.
Furthermore, the driver will return the warning EEL_ERR_FIX_DONE as
an indication that a fix was done. The library operation continues
normally, the application does not need to react on the warning.

DS Write was interrupted
If the DS write proceeded up to writing the DCS, the DS is valid. If the
EOR has not been written, the DS will automatically be refreshed.
In this case additionally Flash write operations might take some more time
and so, enlarge the time until the driver leaves the state
EEL_OPERATION_STARTUP.

DS Write was interrupted
If the DS write did not proceed up to writing the DCS, the DS is invalid.
The start-up process does no special action, but this DS instance is not
considered on DS read.
Application update issues
6.3.7.1 Change DS length
When a user application shall be updated but the EEPROM emulation data
shall be used also further on, different constraints need to be considered with
respect to the ROM ID-L table.
On application update it might be required to change the DS length of some
IDs. Differing from the MF2/UX4 EEELib, this is automatically done, when the
ID-L table in ROM is updated. After that update all DS’s are read/written with
the new length and also the Refresh process copies the data with the new
length:

Old length < new length
Data is extended by any data stored after the DS (data words of the next
DS à undefined)

Old length > new length
Data is cut to new length
Note:
After DS length change, a Read operation will always return a checksum error
(EEL_ERR_WRONG_CHECKSUM) as the checksum does not match to the
DS data (see above) anymore. To fix this, the DS must be written once more
by the application.
Anyhow, differing from the EEELib, the DS length is no longer stored within the
DS, but in the ID-L table. When the table is updated, the information of the
former DS size get lost. So, the library provides no measure to get the length
of the last stored DS instance. This information must be provided otherwise.
User’s Manual U20280EE1V2UM00
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