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152931
NXP B.V. 2010. All rights reserved.
Product data sheet
PUBLIC
Rev. 3.1 — 21 January 2010
152931
23 of 58
NXP Semiconductors
HITAG μ
Transponder IC
10.2 RWD waiting time before sending a subsequent request
When the RWD has received a HITAG μ advanced/advanced+ response to a previous
request other than inventory and quiet, it needs to wait T
Fp2
before sending a
subsequent request. T
Fp2
starts from the time the last bit has been received from the
HITAG μ advanced/advanced+.
When the RWD has sent a quiet request, it needs to wait T
Fp2
before sending a
subsequent request. T
Fp2
starts from the end of the quiet request's EOF (falling edge
of EOF pulse + 42
×
T
C
). This results in awaiting time of (150
×
T
C
+ 42
×
T
C
) before
the next request.
The minimum value of T
Fp2
is T
Fp2min
= 150
×
T
C
ensures that the HITAG μ
advanced/advanced+
ICs are ready to receive a subsequent request.
Remark:
The RWD needs to wait at least 2.33 ms after it has activated the
electromagnetic field before sending the first request, to ensure that the HITAG μ
transponder ICs are ready to receive a request.
When the RWD has sent an inventory request, it is in an inventory process.
10.3 RWD waiting time before switching to next inventory slot
An inventory process is started when the RWD sends an inventory request. For a detailed
explanation of the inventory process refer to
Section 13.3
and
Section 13.4
.
To switch to the next slot, the RWD sends an EOF after waiting a time period specified in
the following sub-clauses.
10.3.1
RWD started to receive one or more HITAG μ transponder IC responses
During an inventory process, when the RWD has started to receive one or more HITAG μ
advanced/advanced+ transponder IC responses (i.e. it has detected a HITAG μ
advanced/advanced+ transponder IC SOF and/or a collision), it shall
wait for the complete reception of the HITAG μ advanced/advanced+ transponder IC
responses (i.e. when a last bit has been received or when the nominal response time
T
NRT
has elapsed),
wait an additional time T
Fp2
and then send an EOF to switch to the next slot, if a 16
slot anticollision request is processed, or send a subsequent request (which could be
again an inventory request).
T
Fp2
starts from the time the last bit has been received from the HITAG μ
advanced/advanced+ transponder IC.
The minimum value of T
Fp2
is T
Fp2min
= 150
×
T
C
.
T
NRT
is dependant on the anticollisions current mask value and on the setting of the CRCT
flag.