ATA559001-DBW Atmel, ATA559001-DBW Datasheet - Page 78

• 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

11. Anticollision Procedures
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ATA5590
ATA5590 supports an Aloha-based selection procedure, a deterministic selection procedure,
and the mixture of deterministic and Aloha.
Additionally, the deterministic anticollision procedure supports non-unique ID structures (migra-
tion path).
To get a first impression about the situation, a wake-up command is transmitted. Each
addressed tag in the field modulates one of the 16-bit slots which are part of the return link. If the
reader has not seen a modulation in more than one slot, then there is the possibility that only
one tag is in the field. After the slot window is closed, the tag backscatters the ID information
automatically.
A deterministic procedure is based principally on long commands containing the command, the
parameter field, and, for special commands, an address field. To minimize the time for determin-
istic anticollision procedures, ATA5590 supports a short command called repeat_arb. After
receiving this command, the last command is repeated if it was received successfully. To solve
problems where the ID is not unique, or to solve the problem of virgin tags, ATA5590 can insert
a 16-bit random value. Then the ID need not be unique.
Deterministic procedures can set status1 flags (storage time 8 seconds without external power
at 25°C). Deterministic anticollision procedures operate in full duplex mode, allowing very fast
operation. The data rate is under the control of the reader. After selection, the tag is free for
operation (reading, programming, etc.).
ATA5590 also supports an Aloha-based anticollision procedure. The system is based on slot
commands (short commands), and a slot value of 32. Each tag calculates a random value at the
beginning of Aloha. This random value is then the slot number during which the tag switches to
an active state (enabling operation and backscattering).
To get a first impression if there is a tag in the field, each tag operates in two slots
The user is free to mix the two anticollision modes.
• The first slot, and
• An additional slot (1 out of the next 31 slots).
4817C–RFID–03/07