Mifare DESFire EV2 Card Removed While writing Data

Forum / MIFARE general topics and applications / Mifare DESFire EV2 Card Removed While writing Data

  • 19. November 2019 at 6:50
    hi, what happens to data in file on card when the card is removed while writing data?
    also, does this operation affects the file, or just the data on file?
    File type: standard
    + 0  |  - 0

    Re: Mifare DESFire EV2 Card Removed While writing Data

    19. November 2019 at 9:37
    Hi Jack,

    If you remove the card while a writing operation is ongoing, then it is undefined what data could be stored and what not. Therefore, a MIFARE DESFire has several file types for this case. For the type “StandardDataFile” this behavior is undefined (the data file might be corrupted). Hence, you should use this file type only for read-only data.

    For updating data in the field, you should use a file of type “BackupDataFile”. This file type allows you to terminate all writing sequences with the command CommitTransaction. With this command all saved data blocks are set as valid. The previous file content is updated. If the user removes the card from the field before CommitTransaction was called, all written data is discarded, and the file is not updated.

    The MIFARE DESFire has other file types: ValueFile, LinearRecordFile and CyclicRecordFile. The “backup mechanism” is also available for these file types.

    The TapLinx team
    + 0  |  - 0
Viewing 2 posts - 1 through 2 (of 2 total)

You must be logged in to reply to this topic.