ATA559001-DBW Atmel, ATA559001-DBW Datasheet - Page 82

• Manufacturer Part Number: ATA559001-DBW
• Description: RF Wireless Misc UHF (1kbit r/w anti- collis. Ni-Au)
• Manufacturer: Atmel

Specifications of ATA559001-DBW

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

13.1
13.2
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Anticollision Status Register
Deterministic Anticollision Procedure in Principle
ATA5590
The status1 register contains the information of the anticollision procedure. A part of this register
can be read out. The value of the status1 register is stored up to 8s (at 25°C) after the supply
voltage falls below an internal POR voltage level. The storage time depends on fabrication toler-
ances and temperature effects, and will increase if the temperature is below 25°C or decrease if
the temperature is higher than 25°C.
After getting power back (POR), the status of the register will be refreshed, which means that the
IC stores back the load information of a capacitor into the register. Therefore, only logical infor-
mation will be refreshed. Due to the leakage current of the circuit, the capacitor loses the stored
information over time. If this charge is less than a certain value, the contents is interpreted as a
logical 0.
To reset the register contents, the carrier must be switched off for a certain amount of time (a
function of the temperature as explained above), or the reader has to send a reset command
(control bit and selection condition must be true).
The stored values are
Group-selection commands affect only the pre_select bit, whereas anticollision commands are
influenced by the ID and the ID_s flags. The reader can use the pre_select and ID flags to con-
trol the functionality of the tag.
After releasing an anticollision procedure by the tag, the backscatter link is controlled by the ID
and ID_s flags. If an anticollision procedure is started, the tag backscatters information to the
reader:
If ID_s is set, the tag must receive a reset command before beginning new communication, or
the RF power must be switched off for a certain time (> 8s at 25°C)
The anticollision procedure is based on the contents of register status1 (ID_s, ID, and
pre_select), and the internal signal arbitration lost. The power-on reset (POR) signal does not
reset this status1 register, but the contents is refreshed during each POR and general reset. The
internal signal arbitration lost is not persistent, meaning that it will be reset if a POR occurs.
• ID_s: The tag was identified (selected) during arbitration, and is in the sleep state now. The
• ID: The tag was identified (selected) during arbitration, and has not received a new
• Pre_select: The tag was identified by a group select command and the result was true. The
• If it has not won an arbitration during the last arbitration field
• If ID is set and ID_s is “0”
• If the reader sends a short command, the tag answers if ID is set and ID_s is ”0”
tag can receive any stream coming from the reader and analyze it, but the tag will not act
unless the reset condition is true.
anticollision command. The reader can communicate with all selected tags.
reader can communicate with all tags which are pre-selected by setting the select bit or
choosing the right short command.
4817C–RFID–03/07