ATA555812C-DDB Atmel, ATA555812C-DDB Datasheet - Page 17

• Manufacturer Part Number: ATA555812C-DDB
• Description: IC IDIC 1KBIT R/W DIE
• Manufacturer: Atmel

Specifications of ATA555812C-DDB

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

5. Operating Modes
5.1
5.2
5.3
5.4
5.5
4681E–RFID–11/09
Interrogator Talks First Mode (ITF)
Tag State Machine
Power Down State
READY State (ITF)
Selected State
After initialization, the Operating Mode (Configuration block bits 23 and 24) is interrogated and
depending on it’s state, the device will go into either the READY state of the “Interrogator Talks
First” (ITF) mode or the Public Mode’s PM READY state if the PM bit is set or the “Electronic
Article Surveillance” (EAS) mode is selected.
For multi-tag applications, the ATA5558 is used in the “Interrogator Talks First” (ITF) mode with
anticollision handling capability. In this mode, the tag starts up in the READY state, where it
remains silent and waits for further interrogator commands before communication can take
place.
Any tag can find itself in one of the following states:
In the state diagram shown in
or removing the field (power on/off) or via one of the commands Select, SelectAll, SelectGroup,
ResetSelected or ResetToReady. When a tag is unable to decode or process an interrogator
command (e.g. CRC or bit frame error), it will remain in the current state. Depending on the
state, tag(s) will only accept certain commands.
The tag is in the Power Down state when there is not enough energy in the interrogator field to
activate the tag. The ATA5558 commences a power-on initialization delay with an activated
weak damping level to achieve a field strength threshold for stable operation.
The ATA5558 tag enters the READY state after it has been activated by the interrogator
(RF-field on) or after receiving either a ResetToReady or ResetSelected command (the EAS and
PM deactivated). The READY state is the initial anticollision state, and in general all tags on this
state are unidentified.
Before a tag can in any way be accessed, it must first be selected. Tag selection can take place
individually in which case they find themselves within the Selected state. They can enter the
Selected state as a result of receiving an explicit Select command with the matching Tag ID. In
this way, only one tag can theoretically be in the Selected state at any one time. If a tag should
find itself in the Selected state and a second tag is selected by a subsequent Select command,
the first tag will automatically proceed into the Quiet state.
• POWER DOWN
• PM READY (for PM or EAS modes only)
• READY (ITF mode)
• SELECTED
• QUIET
Figure 5-1 on page
18, a state transition takes place by applying
ATA5558
17