JP2002312738A - Non-contact ic card device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish appropriate synchronization on an IC card side when erroneously detecting a phase for communication noise in a non-contact IC card device in which the synchronization is established by detecting the phase of data signals received from a reader-writer and non-contact communication is performed with the reader-writer. SOLUTION: After the phase is detected from received data signals 112 by a clock generation circuit 102, a synchronization code in the data signals 112 is detected by a logic circuit 103 and elapsed time from the point of time of detecting the phase is counted by a decision time counter 105. When the synchronization code is not detected before preset standby time elapses, it is considered that the phase detection is an error, retry instruction signals 119 are outputted to the clock generation circuit 102 and the phase is detected again.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact IC card device including a non-contact IC tag device for establishing non-contact communication by establishing synchronization of an internal clock by detecting a phase of a signal received from a reader / writer. In particular, the present invention relates to a countermeasure for shortening a time required for establishing proper synchronization when a phase is erroneously detected for communication noise.

[0002]

2. Description of the Related Art Generally, an IC card device naturally needs means for synchronizing with a data signal from a reader / writer when communicating with a reader / writer. By the way, in the non-contact type IC card device, since the power supply is unstable and is easily affected by noise,
It is not suitable to mount a synchronization circuit such as an LL circuit, and a simpler means for establishing synchronization is required. At that time,
If there is room in the circuit, it is possible to perform data discrimination after oversampling the received data and performing waveform shaping, but the circuit scale becomes large.

[0003] Therefore, in a low-cost non-contact IC card device such as a non-contact IC tag device, phase detection is performed from the edge of a received data signal as a synchronization establishing means that is simpler and requires a smaller circuit scale. Then, a technique of adjusting the phase of the internal clock based on the information is used.

Here, an example of a conventional non-contact IC card device is shown in FIG. In this device, the received signal is converted into a received data demodulated signal 61 by a non-contact data transmission circuit 601.
2 demodulated. Next, the phase detection / clock generation circuit 602 detects the phase of the received data demodulated signal 612 from the signal change point of the received data demodulated signal 612, and uses the phase information and the received carrier signal 613 to generate a data processing clock. A signal 614 is generated. Then, the protocol processing logic circuit 603 performs protocol processing based on the data processing clock signal 614 and outputs the transmission data 615 to the non-contact data transmission circuit 601, and stores the transmission data 615 in the non-volatile memory with the non-volatile memory 604. Data 616 is exchanged.

[0005]

In the above-mentioned non-contact IC card device, when communication noise overlaps with the received data signal, the noise may be erroneously detected in phase. In this case, it is necessary to release the phase synchronization once and perform the phase detection again.

However, in the conventional non-contact IC card device, the IC card cannot determine whether or not the phase detection is for communication noise.
Therefore, on the reader / writer side, it is considered that the phase detection is erroneous when there is no response from the IC card for a long time, and the carrier transmission is temporarily stopped and the re-communication operation is performed. As a result, there is a problem that not only the burden on the system but also the loss of communication time increases.

The present invention has been made in view of the above points, and a main object of the present invention is to provide a non-contact IC card which establishes synchronization of an internal clock by detecting a phase of a received signal to perform non-contact communication. The device focuses on the synchronization code in the received data used for the protocol processing, and by utilizing this synchronization code, when the phase of the communication noise is erroneously detected, the IC card side can detect that. Is to reduce the load on the system by reducing the time required to establish proper synchronization and reduce the loss of communication time.

[0008]

In order to achieve the above object, according to the present invention, the correctness or wrongness of the phase detection is determined by detecting the synchronization code. When the synchronization code is detected, the phase detection is determined to be correct. Judgment was made. However, by itself, it is necessary to wait until the synchronization code is detected.Therefore, a waiting time until the determination is performed is set. If the detection is not performed within the waiting time, the phase detection is determined to be erroneous. To detect the phase again.

According to the first aspect of the present invention, clock generating means for detecting a phase of a data signal received from a reader / writer to generate a clock signal, and the data signal based on the clock signal generated by the clock generating means. A synchronous code detecting means for detecting a synchronous code of a communication protocol from the synchronous code detecting means, which has a preset waiting time, and has a predetermined waiting time, from the time when the clock generating means detects the phase until the waiting time elapses. And a retry unit for causing the clock generation unit to perform phase detection again when the synchronization code is not detected.
Note that the synchronous code in the present invention also includes a substitute code.

According to this configuration, when the synchronization code is not detected within the waiting time, the IC card determines that the phase detection is erroneous, and enters a recovery operation in which the synchronization establishment operation is restarted from the phase detection. As compared with the case where the re-communication operation is performed by judging whether the phase detection is correct on the reader / writer side, the load on the system is reduced and the loss of communication time is reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, the retry means is configured to be capable of changing a waiting time. Then, counting means for measuring the number of retries of the phase detection of the clock generation means by the retry means, and waiting time changing means for changing the waiting time of the retry means based on the number of retries counted by the counting means. Be prepared.

According to this configuration, the waiting time of the retry means is changed every time the phase detection of the clock generating means is performed again. Therefore, when the communication noise is stationary and the waiting time coincides with the noise cycle. Furthermore, a situation in which phase detection for the noise is repeated is avoided. In addition, if the phase detection is repeated because the elapsed time until the detection of the synchronization code is long even though the position detection is appropriate, if the method of changing the waiting time by the waiting time changing means is devised, Such a situation can be easily avoided.

According to a third aspect of the present invention, in the second aspect of the present invention, the waiting time when the synchronous code is detected by the synchronous code detecting means within a certain waiting time is determined by the retry means at the time of detecting the next synchronous code. And an initial value setting means for setting an initial value of the waiting time.

According to this configuration, once the synchronization code is detected from the data signal and the non-contact communication with the reader / writer succeeds once in an arbitrary use environment, the waiting time at that time is the next synchronization time. Since the initial value of the waiting time at the time of code detection becomes, the waiting time is optimized for the usage environment,
The loss of time required to establish proper synchronization is reduced.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows the entire configuration of a non-contact IC card device according to Embodiment 1 of the present invention, and this embodiment corresponds to the first aspect of the present invention.

This non-contact IC card device synchronizes with a non-contact data transmission circuit 101 for receiving and transmitting signals in a non-contact state with a reader / writer (not shown) and a reception signal from the reader / writer. A phase detection / clock generation circuit 102 as clock generation means for generating an internal clock, a protocol processing logic circuit 103 for performing protocol processing, and a non-volatile memory 104 for storing data in a readable manner. ing.

The data transmission circuit 101 demodulates the signal based on the signal received from the reader / writer, outputs a signal 112 after demodulation of the received data, and outputs a received carrier signal 113.

Clock generation circuit 102 receives reception data signal 112 and reception carrier signal 113 from data transmission circuit 101, and detects the phase of reception data signal 112. When the phase is detected, the data processing clock signal 114
And output it.

The logic circuit 103 includes the data transmission circuit 1
In response to the received data signal 112 from the clock signal 01 and the clock signal 114 from the clock generation circuit 102, protocol processing is performed based on the clock signal 114. When transmitting data, the transmission data 115 is transmitted to the data transmission circuit 1.
01, and on the other hand, exchanges the nonvolatile memory storage data 116 with the nonvolatile memory 104.

In this embodiment, the logic circuit 1
03 is configured to detect a synchronization code in the received data signal 112, has a predetermined waiting time T, and, from the time when the phase is detected by the clock generation circuit 102, A determination time counter 105 is provided to cause the clock generation circuit 102 to perform the phase detection again when the synchronization code is not detected by the logic circuit 103 until the waiting time T elapses. In the present embodiment, the logic circuit 103 constitutes a synchronous code detecting means of the present invention, and the determination time counter 105 constitutes a retry means of the present invention.

More specifically, the clock generation circuit 102
When the phase detection signal 117 is output in addition to the clock signal 114 and the phase is not detected, the phase detection signal 117 is made non-active. When the phase is detected, the phase detection signal 117 is made active.

The logic circuit 103 outputs the synchronization code detection signal 120. When no synchronization code is detected, the logic circuit 103 deactivates the synchronization code detection signal 120. When a synchronization code is detected, the logic circuit 103 outputs a synchronization code detection signal. Activate 120.

The determination time counter 105 receives the phase detection signal 117 from the clock generation circuit 102 and the synchronization code detection signal 120 from the logic circuit 103, and sends a clock generation retry instruction signal 119 to the clock generation circuit 102. When the phase detection signal 117 becomes active, the counting of the elapsed time until the synchronization code detection signal 120 becomes active is started, and when the synchronization code detection signal 120 becomes active. The counting operation is stopped.

The waiting time T is set to a constant value T1 (T = T1). When the count time is less than the waiting time T1, the retry instruction signal 119 is made non-active, and when the count time reaches the waiting time T1, the retry instruction signal 119 is made active and the clock generation circuit 102 Instructs re-execution of phase detection. That is, the waiting time T from the time when the phase is detected
When the synchronization code is not detected before 1 elapses, the clock generation circuit 102 performs the phase detection again.

The synchronization establishing operation of the non-contact IC card device configured as described above will be described below.

In the non-contact IC card device, when detecting the phase of the received data signal 112, the clock generating circuit 102 generates a clock signal 114 for data processing using the result and the received carrier signal 113. And outputs the phase detection signal 117 to the determination time counter 105. The logic circuit 103 continuously performs a detection operation on the synchronization code in the received data signal 112 based on the clock signal 114, and activates the synchronization code detection signal 120 for the determination time counter 105 when the synchronization code is detected. I do. Upon receiving the phase detection signal 117 from the clock generation circuit 102, the determination time counter 105 starts counting the elapsed time from when the phase is detected to when the synchronization code detection signal 120 becomes active. The determination is made based on the waiting time T1. When the count time reaches the waiting time T1, that is, when the synchronization code is not detected within the waiting time T1, it is considered that the phase detection is erroneously performed for the communication noise. The retry instruction signal 119 for the clock generation circuit 102 is activated. Upon receiving the retry instruction signal 119, the clock generation circuit 102 temporarily releases the synchronization and performs the phase detection again. At this time, the determination time counter 105 is also reset to the initial state.

On the other hand, when the synchronization code detection signal 120 becomes active within the waiting time T1, it is considered that the phase detection is appropriate for the signal received from the reader / writer, and the determination time counter is determined. 105 maintains the non-active retry instruction signal 119 for the clock generation circuit 102. Thereby, the synchronization of the clock signal 114 is determined, and the logic circuit 103 continues the protocol processing operation based on the clock signal 114.

The synchronization establishing operation of the non-contact IC card device will be further described with reference to FIG. When communication noise is superimposed on an interrogation signal (POLLING) from the reader / writer (R / W), and the clock generation circuit 102 of the IC card mistakenly detects the phase as an appropriate interrogation signal, The generated clock signal 114 has the wrong phase. Therefore, if there is no means for verifying the correctness of the phase detection on the IC card side as in the related art, it is necessary to correctly process the subsequent signal from the reader / writer. Can not.

On the other hand, in the case of this embodiment, the IC
If the synchronization code is not detected within the waiting time T1 on the card side, the phase detection is determined to be erroneous, and the operation of establishing synchronization from the phase detection is performed again. When the synchronization code is detected within the waiting time T1, the proper internal synchronization is determined, and the data from the reader / writer is properly processed.

Therefore, according to the present embodiment, in the non-contact IC card device, the synchronization code is generated by the logic circuit 103 between the time when the phase is detected by the clock generation circuit 102 and the time when the predetermined waiting time T1 elapses. When the phase is not detected, the clock generation circuit 102 is made to perform the phase detection again by the determination time counter 105. Therefore, when the phase is erroneously detected for the communication noise, the error of the phase detection is detected by the IC card. Can judge the situation and start the recovery operation.
Compared with the conventional case, the load on the system can be reduced and the loss of communication time can be reduced.

(Embodiment 2) FIG. 3 shows the entire structure of a non-contact IC card device according to Embodiment 2 of the present invention, and the same parts as those in Embodiment 1 are denoted by the same reference numerals. . This embodiment corresponds to the second aspect of the present invention.

In this embodiment, the judgment time counter 105
Is a variable judgment time counter capable of changing the waiting time T. Then, a detection number counter 10 as a counting means for measuring the number of re-detections of the phase of the clock generation circuit 102 by the variable judgment time counter 105
7 and the number of redoes counted by the detection number counter 107, the determination time variable counter 10
5 is provided with a time setting circuit 108 as a waiting time changing means for changing the waiting time T.

Specifically, the detection number counter 107 is
Retry instruction signal 119 of variable judgment time counter 105
Is detected, the number of times of detection is counted, and data obtained by the detection is output to the time setting circuit 108 as detection number count data 121. On the other hand, the time setting circuit 108 has, for example, a correspondence table between the number of times of detection and a time value created in advance, and an arithmetic expression for calculating a time value using the number of times of detection. Basically different time setting value 1
22 is output to the variable judgment time counter 105. Also,
The determination time variable counter 105 has the time setting value 122
Is used as the waiting time T to determine the elapsed time from the phase detection time. The other configuration is the same as that of the first embodiment, and the description is omitted.

The synchronization establishing operation of the non-contact IC card device configured as described above will be described below.

In the non-contact IC card device, when the phase detection of the clock generation circuit 102 is performed one or more times, every time the retry instruction signal 119 of the variable determination time counter 105 becomes active, the detection number counter 107 Detects this, measures the number of times of detection, and outputs it to the time setting circuit 108 as detection number count data 121. The time setting circuit 108 sets a time value in accordance with the value of the number-of-detections count data 121, and outputs the time value as the time setting value 122 to the determination time variable counter 105. As a result, the waiting time T of the variable determination time counter 105 is changed based on the number of times the phase detection is performed again. Then, the determination time variable counter 105 determines the elapsed time based on the changed waiting time T every time the position detection is performed again.

Here, a state transition on the IC card side under an environment where a system-specific steady communication noise occurs before an interrogation signal (POLRING) from a reader / writer (R / W) will be described. This will be described in comparison with the first embodiment with reference to FIG. First, Embodiment 1
In the case of (2), as shown in FIG. 4B, the waiting time T from the detection of the phase to the detection of the synchronization code is constant (T
= T1), the phase detection is always performed on the communication noise if the cycle of the phase detection redoing coincides with the generation cycle of the communication noise. It is difficult to establish proper synchronization under the influence of.

On the other hand, in the case of this embodiment, FIG.
As shown in (a), the waiting time T changes (T = T1, T
2, ...), so the effects of stationary noise are eliminated,
Therefore, correct synchronization can be established.

Therefore, according to the present embodiment, in the non-contact IC card device, the determination time counter 1 for determining whether or not the elapsed time from the phase detection has reached the waiting time T.
Reference numeral 05 denotes a variable determination time variable counter for the waiting time T, a detection number counter 107 for detecting that the retry instruction signal 119 of the variable determination time counter 105 has become active and counting the number of detections. The time setting circuit 108 for changing the waiting time T of the variable judgment time counter 105 according to the number of detections counted by the number of times counter 107 is provided, so that proper synchronization can be achieved even under the influence of steady communication noise. The time required for establishment can be reduced.

If the time required for detecting the synchronization code is exceeded and the synchronization is released, despite the fact that the phase detection is appropriate, the method of changing the waiting time T may be simply improved. Such a situation can be easily avoided.

(Embodiment 3) FIG. 5 shows the entire structure of a non-contact IC card device according to Embodiment 3 of the present invention, and the same parts as those in Embodiment 2 are denoted by the same reference numerals. ing. This embodiment corresponds to the third aspect of the present invention.

In the present embodiment, the logic circuit 103
The waiting time T when the synchronization code is detected by the logic circuit 103 and proper synchronization is determined is set to the time setting circuit 1.
08 is set to the initial value, and the logic circuit 103 constitutes an initial value setting means in the present invention.

More specifically, the logic circuit 103 inputs the time setting value 122 to itself each time the time setting circuit 108 outputs the time setting value 122, and outputs the time setting value 122 when the synchronization code is detected. While the data is stored in the non-volatile memory 104, the time setting value 122 is read from the non-volatile memory 104 at the time of detecting the synchronization code at the time of the next non-contact communication with the reader / writer, and the time setting initial value 12 is read.
3 is output to the time setting circuit 108. The time setting circuit 108 outputs the time setting initial value 12
3 is output to the determination time variable counter 105 as the first time setting value 122.

The synchronization establishing operation of the contactless IC card device configured as described above will be described below.

In the non-contact IC card device, the phase detection of the clock generation circuit 102 is performed one or more times, and when the time setting circuit 108 outputs the time setting value 122 based on the number of times of the redoing, the time is used. The set value 122 is input to the logic circuit 103 in addition to the determination time variable counter 105 each time. Then, as a result of performing several times, when the proper synchronization is successfully established, the logic circuit 103 sets the time setting value 122 at that time to:
The data is stored in the nonvolatile memory 104.

Thereafter, when a new non-contact communication with the reader / writer is started next time, the logic circuit 103
The time setting value 122 is read from the non-volatile memory 104 and is output to the time setting circuit 108 as the time setting initial value 123 of the waiting time T. And the time setting circuit 1
08 sets the time setting initial value 123 to the time setting value 122
Is output to the variable judgment time counter 105, and the variable judgment time counter 105 generates a clock based on the time setting value 122, that is, the waiting time T when the appropriate synchronization is successfully established at the start of the previous non-contact communication. Circuit 102
From the time when the phase is detected by the logic circuit 103
To determine the elapsed time until the synchronization code is detected.

Therefore, according to the present embodiment, the value of the waiting time T when synchronization is successfully established is used as the initial value at the time of determining the next elapsed time. The time T can be optimized, so that the time loss until the proper synchronization is established and the system load can be efficiently reduced.

In the first to third embodiments, the detection of the phase by the clock generation circuit 102 is recognized by the phase detection signal 117 of the clock generation circuit 102. However, the detection is performed by other means. You may make it.

In the first to third embodiments, the synchronization code detecting means (including the initial value setting means in the case of the third embodiment) is constituted by the logic circuit 103. It is also possible to configure with other things.

Further, in the first to third embodiments, the case of a non-contact IC card device is described, but the present invention can be applied to a non-contact IC tag device and the like.

[0051]

As described above, according to the first aspect of the present invention, when a synchronization code is not detected until a predetermined waiting time elapses from the phase detection, the phase detection is performed again. As a result, it is possible to determine again whether or not the phase detection was erroneously performed with respect to communication noise and restart the synchronization operation, thereby reducing the load on the system and reducing the communication time. Loss can be reduced.

According to the second aspect of the present invention, since the waiting time is changed according to the number of times of redoing, it is possible to avoid the situation where the redoing of the phase detection is repeated due to the influence of stationary noise. Communication time loss under such a use environment can be reduced.

According to the third aspect of the present invention, the waiting time when the proper synchronization is successfully established is set as the initial value at the time of the next synchronization establishment, so that the waiting time can be optimized for the use environment. It is possible to further reduce communication time loss.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a non-contact IC card device according to Embodiment 1 of the present invention.

FIG. 2 is a timing chart showing correspondence between received data and state transition on the IC card side when communication noise is superimposed on an interrogation signal from a reader / writer (R / W).

FIG. 3 is a diagram corresponding to FIG. 1, illustrating an entire configuration of a non-contact IC card device according to a second embodiment of the present invention.

FIG. 4 shows a correspondence relationship (a) between received data and a state transition on the IC card side in the second embodiment when communication noise is present on an interrogation signal from a reader / writer (R / W) in the first embodiment. It is a timing chart figure shown in comparison with case (b).

FIG. 5 is a diagram corresponding to FIG. 1 showing an overall configuration of a non-contact IC card device according to a third embodiment of the present invention.

FIG. 6 is a diagram corresponding to FIG. 1 showing the overall configuration of a conventional non-contact IC card device.

[Explanation of symbols]

Reference Signs List 102 Phase detection / clock generation circuit (clock generation means) 103 Protocol processing logic circuit (synchronization code detection means, initial value setting means) 105 Judgment time counter, judgment time variable counter (retry means) 107 Detection count counter (counting means) 108 Time setting circuit (waiting time changing means) 112 Received data demodulated signal (data signal) 114 Data processing clock signal (clock signal)

Claims (3)

[Claims] 1. A clock generating means for detecting a phase of a data signal received from a reader / writer to generate a clock signal, and a synchronization code of a communication protocol from the data signal based on the clock signal generated by the clock generating means. And a synchronization code detecting means for detecting the synchronization code. The synchronization code detecting means has a predetermined waiting time, and the synchronization code detecting means detects the phase of the synchronization code between the time when the phase is detected by the clock generation means and the time when the waiting time elapses. A non-contact IC card device, comprising: retry means for causing the clock generation means to perform phase detection again when no is detected. 2. The non-contact IC card device according to claim 1, wherein the retry means is configured to be capable of changing a waiting time, and a counting means for measuring the number of times the clock generation means performs the phase detection again by the retry means; A non-contact IC comprising a waiting time changing means for changing a waiting time of the retry means based on the number of redoes counted by the counting means.
Card device. 3. The non-contact IC card device according to claim 2, wherein the waiting time when the synchronization code is detected by the synchronization code detection means within a certain waiting time is retried when the next synchronization code is detected. A non-contact IC card device comprising an initial value setting means for setting an initial value of the waiting time.