
184430
All information provided in this document is subject to legal disclaimers.
NXP B.V. 2010. All rights reserved.
Product data sheet
PUBLIC
Rev. 3.0 — 18 March 2010
184430
15 of 44
NXP Semiconductors
HITAG μ
ISO 18000 transponder IC
11.2 RWD waiting time before sending a subsequent request
When the RWD has received a HITAG μ ISO 18000 response to a previous request
other than inventory or 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
ISO 18000.
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 a waiting 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 ISO 18000 ICs
are ready to receive a subsequent request.
Remark:
The RWD needs to wait at least 2.5 ms after it has activated the electromagnetic
field before sending the first request, to ensure that the HITAG μ ISO 18000 transponder
ICs are ready to receive a request.
When the RWD has sent an inventory request, it is in an inventory process.
11.3 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 14.3
and
Section 14.4
.
To switch to the next slot, the RWD sends an EOF after waiting a time period specified in
the following sub-clauses.
11.3.1
RWD started to receive one or more HITAG μ ISO 18000 transponder IC
responses
During an inventory process, when the RWD has started to receive one or more HITAG μ
a ISO 18000 transponder IC responses (i.e. it has detected a transponder IC SOF and/or
a collision), it shall
wait for the complete reception of the HITAG μ ISO 18000 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 ISO 18000
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.