ATA555814C-DBB Atmel, ATA555814C-DBB Datasheet - Page 20

• Manufacturer Part Number: ATA555814C-DBB
• Description: IC IDIC 1KBIT R/W SAWN WAFER
• Manufacturer: Atmel

Specifications of ATA555814C-DBB

• Function: Read/Write
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 5-3.
6. Anticollision Protocol
20
ATA5558
POR
EAS Startup
initialisation
delay
POR
Check Operating
Mode (= EAS)
The aim of the anticollision protocol and associated arbitration process is to detect and identify
the Tag ID’s of all tags within the READY state which are present within range of the interrogator
field.
The interrogator masters all communication with single or multiple tags. Tag arbitration commu-
nication is initiated by issuing the GetID command. All tags in the READY state will then enter
the anticollision detection loop and synchronously start to transmit an identification response
that represents the tag’s individual unique Tag ID code. Using an iterative bit-wise sorting algo-
rithm on these Tag ID’s, the interrogator is capable of eliminating all but one tag. This remaining
tag is thus selected and can be accessed directly by following commands. Tags eliminated dur-
ing the detection loop are muted, drop back into the READY state to participate in the next
detection cycle.
A typical anticollision procedure is illustrated in the following scheme:
a) The interrogator starts the anticollision detection by sending a GetID command.
Any previously eliminated and muted tag will be put into the READY state. All tags in the
READY state participate initially in the anticollision detection loop.
If nothing is known of the Tag ID’s within range, then the GetID command includes no further
parameters and the detection group encompasses all tags. After a predefined number of
field clock cycles, all tags within range reply by synchronously transmitting a SOF pattern
followed by their own respective Tag ID(MSB).
Anticollision detection can be reduced to a subgroup of tags by passing a partial Tag ID pat-
tern as Tag ID command parameter. These bits represent the most significant bits of the
Tag ID subgroup. Anticollision detection will then be carried out on this subgroup, continuing
as above with the synchronous reply from all constituent tags, followed by their most signifi-
cant unknown Tag ID bit(s).
(Block 0 = all '0's)
"Unpaid" Device
POR
initialisation
delay
POR
Check Operating
Mode (= EAS)
(Block 0 = all '1's)
"Paid" Device
4681E–RFID–11/09