ATA555811C-DDB Atmel, ATA555811C-DDB Datasheet - Page 19

• Manufacturer Part Number: ATA555811C-DDB
• Description: IC IDIC 1KBIT R/W DIE
• Manufacturer: Atmel

Specifications of ATA555811C-DDB

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

5.6
5.7
5.8
4681E–RFID–11/09
Quiet State
Public Mode (PM) and PM READY State
Electronic Article Surveillance (EAS)
The tag goes into the Quiet state from the Selected state when a new selection takes place i.e. a
Select or a GetID command is received. Unlike the READY state, the tag’s Tag ID in this state is
known. Tags in the Quiet state are excluded from subsequent anticollision detection.
In the Public Mode, communication commences with a single “Start of Frame” pattern (SOF), fol-
lowed by a continuous stream of serialized user data which is read cyclically from the user
memory. This starts with block 0, bit 31 and continues sequentially through to bit 0 of the final
block address defined by the configuration parameter MAXBLOCK. After reaching the MAX-
BLOCK address, data transmission repeats with block 0, bit 31. If, for example MAXBLOCK
were set to 1, block 0 and 1 would be continuously transmitted. This transmission process con-
tinues indefinitely until terminated by either switching the field off or on the receipt of a valid
interrogator command.
On the start of a new command the tag will proceed temporarily from the PM READY state into
the (ITF) READY state. If the command is valid, it will be executed and the tag state changes as
if in the ITF mode (see
into the PM READY state and continue to transmit data. To restart the public mode transmis-
sion, the tag must be re-initialized by reapplying the field (POR) or by using a ResetToReady
command.
Figure 5-2.
The EAS Mode is intended for retail article surveillance whereby the device will be physically
attached to retail articles in a store or supermarket. The device will be preprogrammed into an
”unpaid state” before entering the sales area by programming the block 0 to MAXBLOCK of the
user memory to all 0s. For convenience reasons MAXBLOCK should be set to 0 in the configu-
ration word. To increase security, the memory pages containing block 0 to MAXBLOCK should
be assigned a write password security level (see password protection). Once the article has
been purchased at the cash desk, the device is programmed into a “paid state” by writing the
block 0 with all 1 s, using the appropriate password (if necessary). As soon as an “unpaid”
device enters an interrogator field, it will modulate the interrogator field with an RF/2 signal. This
can be detected by the surveillance interrogator and used to trigger an appropriate audio or
visual warning. A “paid” device will remain silent. As in the Public Mode, the device will revert to
ITF mode READY state as soon as it receives a valid interrogator command. By reapplying the
field (POR) or using a ResetToReady command, the device returns to EAS mode.
POR
initialisation
Public Mode Start Up
delay
POR
Check Operating
Mode (= PM)
Figure 5-1 on page
Start of Frame
(SOF)
31 30
1
0
Data Block 0
29
18). If the command is invalid, then it will drop back
0
28
1
27
1
26
0
25
0
Example data values
4
1
Bit position
(Maxblock )
Data Block
3
0
2
0
1
1
0
1
31 30
1
0
Continue from
Data Block 0
29
0
28
ATA5558
1
27
1
26
0
19