ATA559001-DDT Atmel, ATA559001-DDT Datasheet - Page 33

• Manufacturer Part Number: ATA559001-DDT
• Description: RF Wireless Misc UHF (1kbit r/w anti-collision)
• Manufacturer: Atmel

4.9.7
4.9.8
4.10
4817C–RFID–03/07
Summary of the Supported Arbitration Possibilities
Mute State
Isolate State
The mute state is quite similar to the select state. However, as the select condition was false, the
tag remains silent, and no operation (such as programming, arbitration or backscattering data) is
done.
The isolate state is also quite similar to the select state. The tag is isolated and waits on a
power-on reset or a reset command, which will reset the ID_s flag of the status1 register.
If more than one tag is in the RF field and ready to operate, the system must support an arbitra-
tion procedure to be able to select one or a group of tags for further operations (for example,
program or read), or to identify them.
The system must also be able to isolate a tag after an operation to be sure that this tag does not
disturb the following communications. The flag which indicates this silent mode is ID_s, one of
the status1 register bits.
Furthermore, in some applications it is helpful to get a first impression of whether there are sev-
eral tags in the field or not. Therefore, the ATA5590 supports wake-up commands. After the
return link header, the protocol supports a slot zone containing 16 bits. A tag modulates one of
the 16 slots (the select mechanism for the slot is based on a random value calculated on-chip).
ATA5590 supports two kinds of principal arbitration mechanisms:
ATA5590 can mix these procedures, yielding a two-level arbitration mechanism.
The deterministic procedure can be combined with a random approach to be able to handle data
structures in the arbitration process which are not unique. This random approach is not
Aloha-based, and, therefore, strongly deterministic.
The result of each procedure is stored in the register status1.
Aloha-based procedures also influence the ID_s flag, and are able to consider the flags
pre_select and ID.
Aloha is controlled by slot commands. The close slot command finishes the Aloha arbitration.
After POR, the tag starts to calculate a random value. The calculation continues as long as the
tag receives power.
• A deterministic-arbitration procedure which is able to handle hierarchical processes, and
• An Aloha-based procedure which is time-slot-based. The size (time and bit count) of such a
slot is under control of the reader
ATA5590
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