Change Request
NFC Forum Committee
Title:
ACM ATR_RES Timeout Value
To:
Technical Committee
Document to
be changed:
Digital Protocol 2.0 Candidate
Submitting
Companies:
Sony Corporation
Contact
Details:
Klaus Röhrle <Klaus.Roehrle@eu.sony.com>
Katsuyuki Teruyama <Katsuyuki.Teruyama@jp.sony.com>
Date:
12 October 2015
Replaces:
N/A
Classification:
Reason for Change
We see a problem with the current timeout value for ATR_RES in response to the
ATR_REQ. The timeout value RWT (RWTNFCDEP,ACTIVATION = 4096×212) is defined in Digital
Protocol TS 2.0 Candidate. This value is approximately 1.2 sec.
This timeout value is applied to both of passive and active communication modes.
The problematic situation happens when a mobile phone as the polling device is tapped to
the R/W that always generates an operating field and sends poll commands periodically
like transport gate system.
More precisely, the polling device enters in the operating field of the R/W just after the
Initial RFCA followed by generating a field and then sending an ATR_REQ Command.
The polling device follows the flow of Technology Detection Activity (section 9.2.3) as
defined in Activity TS 2.0 Candidate.
In symbol 4, the device detects the remote field generated by the R/W because it always
generates the field. Then go to symbol 5.
In symbol 5, the device waits for ATR_RES, but the R/W never sends ATR_RES but
sends poll commands periodically. It is interpreted as invalid response, then ignored and
the device waits for ATR_RES for 1.2 sec at maximum.
The R/W sends poll commands periodically, but it interpreted as invalid response, then
ignored and the device waits for ATR_RES.
After that, in symbol 9, the device will not detect the remote field off as the R/W does not
stop generating the field and then ends up with listen mode.
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Finally, the device in listen mode can respond to the R/W.
However, 1.2 sec is a big problem for the user to go through the transport gate because
the user has to wait 1.2 sec before the R/W starts the transaction for the transport gate
system.
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Passive
Communication
Mode
Active Communication Mode
Poll Mode
Listen Mode
Device-A
Timeout, then move to Listen Mode
ATR_
REQ
Res
Device-A does not detect
Remote Field here since it is
far from the R/W.
GTACM >= 5.1ms
RWTNFCDEP,ACTIVATION = 1.2 s at maximum
R/W
Poll
Poll
Poll
Poll
Poll
There might be another interpretation on receiving an erroneous response when waiting
for a response to the ATR_REQ, that is, the polling device might immediately stop
receiving another response and then conclude the Technology Detection Activity and
move to the Listen Mode.
However, as the behavior is not clear, defining the new ATR_RES Timeout would avoid
the case where the polling device waits for long duration for a response.
This CR proposes to define a timeout value for ATR_RES in active communication mode.
As the timeout value should be similar to poll command of other technologies, this CR
proposes approx.38 ms ((256 × 16/fC) × 27) for the value.
IPR
Input in this document is subject to the Intellectual Property Rights Policy of NFC Forum,
Inc. A member who is submitting technology for inclusion in a Specification must confirm
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that all controlled necessary claims included in this submission will be licensed on RAND
conditions.
Recommendation
The detailed description should be incorporated into the specification accordingly.
Detailed Description of Proposed Change
The proposal is to introduce a new timeout value for ATR_RES in Active Communication
Mode, which is used during Technology Detection Activity.
The proposal also contains some editorial updates.
<Update the following section with track changes>
17.11.2
Response Waiting Time
The Response Waiting Time (RWT) defines the maximum amount of time a Target has between the end of a
Poll Frame and the SoD of its Response. It is calculated by the following formula:
RWT = (256 × 16/fC) × 2WT
where the value of WT has the range from 0 to 14. WT is included in the ATR_RES Response as specified in
Section Error! Reference source not found..
NOTE
The RWT and the Frame Delay Time PollListen are both started after the receipt of a Poll
Frame. The Target sends the Response in the time interval between the minimum Frame Delay
Time PollListen and RWT. For the Frame Delay Time the SoF of the Response is relevant as
defined in Section Error! Reference source not found., whereas for the RWT it is the SoD as
defined in Section Error! Reference source not found..
The RWT does not impose any limit on the timing of the Initiator; the delay before sending the
next Command is only constrained by the relevant Frame Delay Time ListenPoll.
For the Technology Detection Activity in Active Communication Mode, the following specific RWTs are
defined:

RWTACM,NFCDEP,ACTIVATION
A specific RWT is defined for the ATR_REQ Command in Active Communication Mode. For this
Command, the Target starts sending its Response frame within RWTACM,NFCDEP,ACTIVATION (response
waiting time). Refer to Section Error! Reference source not found. for the definition of the ATR_REQ
Command.
For the Device Activation Activity and the Data Exchange Activity, the following specific RWTs are
defined:

RWTNFCDEP,ACTIVATION
A specific RWT is defined for the ATR_REQ Command in Passive Communication Mode. For this
Command, the Target starts sending its Response frame within RWTNFCDEP,ACTIVATION (response waiting
time). Refer to Section Error! Reference source not found. for the definition of the ATR_REQ
Command.
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NOTE

The response waiting time RWTNFCDEP,ACTIVATION is introduced and defined in this document.
RWTINT
When the Target sends an RTOX Request with a specific RTOX value, the Initiator waits for RWTINT
for the next PDU. Refer to Section Error! Reference source not found. for the definition of RWTINT.
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Requirements 1: Response Waiting Time
Initiator
Target
17.11.2.1
Following the ATR_REQ
17.11.2.2
Command in Passive
Communication Mode, the
Initiator SHALL wait at least
RWTNFCDEP,ACTIVATION +
RWTNFCDEP for the SoD of the
ATR_RES Response.
Between RWTNFCDEP,ACTIVATION +
RWTNFCDEP and
RWTNFCDEP,ACTIVATION +
RWTNFCDEP +
TNFCDEP,INITIATOR, the Initiator
MAY accept the ATR_RES
Response or MAY generate a
Timeout Error.
If the Initiator does not receive the
SoD of the ATR_RES Response
within RWTNFCDEP,ACTIVATION +
RWTNFCDEP +
TNFCDEP,INITIATOR, then the
Initiator SHALL treat this as a
Timeout Error.
Refer to Appendix 17.11.2 for the
value of RWTNFCDEP and
TNFCDEP,INITIATOR.
Following the EoD of the
ATR_REQ Command in Passive
Communication Mode, the Target
SHALL wait no longer than
RWTNFCDEP,ACTIVATION before
sending the SoD of the ATR_RES
Response.
Refer to Appendix 17.11.2 for the
value of RWTNFCDEP,ACTIVATION.
17.11.2.3
Following the ATR_REQ
17.11.2.4
Command in Active
Communication Mode, the
Initiator SHALL wait at least
RWTACM,NFCDEP,ACTIVATION +
RWTNFCDEP for the ATR_RES
Response.
If the Initiator does not receive the
SoD of the ATR_RES Response
within RWTACM,NFCDEP,ACTIVATION
+ RWTNFCDEP, then the Initiator
SHALL treat this as a Timeout
Error.
Following the EoD of the
ATR_REQ Command in Active
Communication Mode, the Target
SHALL wait no longer than
RWTACM,NFCDEP,ACTIVATION before
sending the SoD of the ATR_RES
Response.
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Initiator
17.11.2.5
Target
Except for the ATR_REQ
Command, the Initiator SHALL
wait at least RWT + RWTNFCDEP
for the SoD of the Response from
the Target.
Between RWT + RWTNFCDEP
and RWT + RWTNFCDEP +
TNFCDEP,INITIATOR, the Initiator
MAY accept the Response or
MAY generate a Timeout Error.
17.11.2.6
Except for the ATR_REQ
Command following the EoD of a
Command, the Target SHALL
wait no longer than RWT before
sending the SoD of the Response.
17.11.2.8
After receiving the RTOX
Response PDU of the Initiator, the
Target SHALL send the SoD of
the next PDU within RWTINT.
If the Initiator does not receive the
SoD of the Response from the
Target within RWT +
RWTNFCDEP +
TNFCDEP,INITIATOR, then the
Initiator SHALL treat this as a
Timeout Error.
17.11.2.7
After sending the RTOX
Response PDU in response to an
RTOX Request PDU from the
Target, the Initiator SHALL wait
for RWTINT + RWTNFCDEP for
the SoD of a PDU of the Target.
Between RWTINT + RWTNFCDEP
and RWTINT + RWTNFCDEP +
TNFCDEP,INITIATOR, the Initiator
MAY accept the PDU or MAY
generate a Timeout Error.
If the Initiator does not receive the
SoD of a PDU from the Target
within RWTINT + RWTNFCDEP +
TNFCDEP,INITIATOR, then the
Initiator SHALL treat this as a
Timeout Error.
17.11.2.9
The Initiator SHALL apply
RWTINT + RWTNFCDEP only
until the next PDU has been
received from the Target.
17.11.2.10 The Target SHALL apply
RWTINT only until the next PDU
has been sent by the Target.
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For NFC-F frame timing, the FDTF,LISTEN,MAX defined in Section Error! Reference source not found.
equals RWT - 16 bd (where 16 bd is the bit duration of the SoF). Similar for the ATR_REQ, the
FDTF,LISTEN,MAX,ATR equals RWTNFCDEP,ACTIVATION - 16 bd.
B.10 NFC-DEP Protocol
Table 1: NFC-DEP Protocol Poll Mode and Listen Mode Parameter Values
Parameter
Initiator Value
Min
Target Value
Max
Min
Units
Max
WTNFCDEP,MAX
14
RWTNFCDEP
16
1/fC
TNFCDEP,INITIATOR
100
ms
RWTNFCDEP,ACTIVATION
4096×212
4096×212
1/fC
RWTACM,NFCDEP,ACTIVATION
4096×27
4096×27
1/fC
14
tNFCDEP,RETRANSMISSION
0
4096×212
nNFCDEP,RETRY,NACK
1
4
nNFCDEP,RETRY,ATN
1
4
nNFCDEP,TO,MAX
2
5
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-
1/fC