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XRAG2_08 Datasheet, PDF (25/33 Pages) STMicroelectronics – 432-bit UHF, EPCglobal Class1 Generation2 and ISO 18000-6C, contactless memory chip with user memory
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XRAG2
XRAG2 command descriptions
Figure 18. Reader-to-tag and tag-to-reader communication timings
Reader
Select
Carrier Wave
Query
ACK
t4
RN16
t1
t2
t1
Carrier Wave
QueryRep
PC + EPC + CRC16
t2
NAK
QueryRep or
QueryAdjust
if EPC is valid
NAK is EPC
is invalid
Reader
Tag
Collided Reply
No Reply
Carrier Wave
Query
QueryRep
Invalid ACK
Carrier Wave
QueryRep
ACK
QueryRep
Collision
detected
RN16
t1
t2 t1
No
Reply
t3
t1
RN16
t2
No
Reply
t3
t1
ai12334b
Table 10. Reader-to-tag and tag-to-Reader communication timings(1) (2) (3) (4)
Parameter Description
Conditions
Min
Nominal
Max
T1(5)
Delay between Measured between the
end of Reader
command and
beginning of tag
last rising edge of Reader
command signaling and
the first rising edge of tag
max(RTcal, 10 Tpri) max (RTcal,
× (1_FT) – 2µs
10
Tpri)
max(RTcal, 10 Tpri)
× (1_FT) + 2µs
answer.
reply
T2(6)
Delay between
tag reply and
next Reader
command.
Measured from the last
falling edge of the last bit
of tag reply to the first
falling edge of reader
command signaling.
3.0 Tpri
20 Tpri
T3
Reader waits T1 before issuing new
command when the tag does not reply.
0 Tpri
T4 Minimum time between reader command
2.0 RTcal
1. Tpri = 1/ LF, denotes either the period of an FM0 symbol or a single Miller subcarrier.
2. Characterized only.
3. If a Reader issues a new command during an tag reply, it does not demodulate the command.
4. See EPCglobal Class 1 generation 2 RFID UHF specification, revision 1.0.9 for more detailed information.
5. FT is the tag-to-reader link frequency tolerance.
6. maximum value of T2 only applies on tags in Reply or Acknowledged state. In this case, if T2 expires:
– without receiving a valid command, the tag returns to the Arbitrate state
– during the reception of a valid command, the tag executes the command
– during the reception of an invalid command, the tag returns to the Arbitrate state upon determining that the command is
invalid
– In all other states, the maximum value of T2 does not apply.
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