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e5561
4699A–RFID–04/03
Every section consists of one or more EEPROM blocks. Programming is carried out by
sending the programming data sequence to the e5561. When the base station sends
data to the transponder, this direction of data transmission will be designated as 'write'.
When the base station has sent the data sequence and the specified block has been
programmed, the e5561 transmits the content of the programmed EEPROM block. The
content is always sent in loop with terminator 1. The beginning of the data stream is indi-
cated by a preburst.
During programming, the e5561 monitors several fault and protection mechanisms. If a
fault or a protection violation is detected, the e5561 switches to ID mode.
Direct-access Mode
If the base station transmits a special data sequence to the e5561, it will enter the direct-
access mode. The base station can activate two different functions:
Read the content of a single block of the EEPROM
In this case, the e5561 transmits the block's content in loop, starting with a preburst
followed by the terminator which is also used to indicate the beginning of the trans-
mission of the specified block data.
Reset the e5561 in case of all modes
During direct-access mode, the e5561 monitors several fault and protection mecha-
nisms. If a fault or a protection violation is detected, the e5561 switches to ID mode.
Crypto Mode
In crypto mode, a non-linear high-security encryption algorithm called AUT64 is used to
authenticate the e5561.
After the base station has identified the e5561 (i.e., read the ID code), the base station
may authenticate the transponder by transmitting a challenge. Receiving this data
sequence causes the e5561 to switch to crypto mode.
This initiates the following actions:
While calculating the AUT64 result, the transponder transmits the checksum of the
challenge
The e5561 generates the response from the calculated result of the AUT64
As soon as the calculation is finished, the e5561 interrupts the transmission of the
checksum by sending a terminator
The e5561 transmits the response in loop with a terminator back to the base station
The base station can read the response and authentify the transponder. It is possible to
interrupt the calculation of the AUT64 result by sending another data sequence (e.g., if
the checksum was found to be wrong).
During crypto mode, the e5561 monitors several fault and protection mechanisms. If a
fault or a protection violation is detected, the e5561 enters ID mode.
Stop Mode
If two or more transponders are used simultaneously (e.g., in a manufacturing step), it
might be useful to be able to set the transponders to a passive state. To avoid a commu-
nication conflict, the base station has to transmit a special data sequence to the active
transponder(s) forcing them to switch to stop mode.
In stop mode, the e5561 switches off the damping as long as the RF field is applied.
After a power-on reset or after having received the software-reset command, the e5561
enters start-up and ID mode again.
During the data sequence of the stop mode, the e5561 monitors fault mechanisms. If a
fault is detected, the e5561 enters ID mode.