CN103595420B - Decode the decoder for the TYPE a-signals that card reader is sent - Google Patents
Decode the decoder for the TYPE a-signals that card reader is sent Download PDFInfo
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- CN103595420B CN103595420B CN201210286884.2A CN201210286884A CN103595420B CN 103595420 B CN103595420 B CN 103595420B CN 201210286884 A CN201210286884 A CN 201210286884A CN 103595420 B CN103595420 B CN 103595420B
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Abstract
The decoder of the TYPE a-signals sent the invention discloses card reader in a kind of decoding agreements of ISO/IEC 14443, including：One counter, the counter reset during the groove of data waveform is received, counted between data waveform high period is received；One state machine, the state machine have 3 states, respectively X states, Y states, Z condition；The original state of the state machine is Z condition；The State Transferring of the state machine is determined by current state and the count value of counter with the one group of threshold value set result of the comparison；One decode logic circuit, the status switch of decode logic circuit state machine according to receive process, decode the TYPE a-signals that card reader is sent, including start of frame delimiter, data and frame end mark.Existing decoding circuit, the reception signal in half of data cycle can only be less than to the groove time and is decoded.And the present invention can not only decode reception signal of the groove time less than half of data cycle, moreover it is possible to decode reception signal of the groove time more than half of data cycle.
Description
Technical field
The present invention relates to field of intelligent cards, decodes card reader in the agreements of ISO/IEC 14443 more particularly to one kind and sends
TYPE (type) a-signal decoder.
Background technology
Used in the TYPEA signals that card reader is sent in the agreements of ISO/IEC 14443 is the amendment of very amplitude modulation(PAM)
Miller signal (ASK 100%Modified Miller).The data encoding for the TYPE a-signals that card reader is sent has 3 kinds of waveforms,
X, Y and Z waveform are referred to as, its oscillogram is referring to shown in Fig. 1~3.First half cycle of the X waveforms in the data cycle is logic 1,
First there is the logical zero of lasting W times in the later half cycle in data cycle, is then logic 1 again.Y waveforms are all in the whole data cycle
Logic 1.Z waveforms have the logical zero of lasting W times in the incipient stage in data cycle, are then logic 1 again.In this 3 kinds of waveforms
Logical zero part is also referred to as " groove ".
In the agreements of ISO/IEC 14443, the coding rule for the TYPE a-signals that card reader is sent is as follows：
In the incipient stage of every frame data signals, start of frame delimiter is first sent, then sends signal wave corresponding with data
Shape, finally send frame end mark.
Start of frame delimiter is a Z waveform.Frame end mark is different and different according to the last value for sending bit, if
The value for finally sending bit is 1, then frame end mark is two continuous Y waveforms；If the value for finally sending bit is 0,
Frame end mark is that a Z waveform closelys follow a Y waveform.
Waveform is described as follows corresponding to other data：
If first transmission data, then if it is 0 to send data, send Z waveforms；If it is 1 to send data,
Then send X waveforms.
When not being first transmission data, if it is 0 to send data, then to see that previous bit sends data.Such as
It is also 0 that the previous bit of fruit, which sends data, then sends Z waveforms；If it is 1 that previous bit, which sends data, Z waveforms are sent.
When not being first transmission data, if it is 1 to send data.So send X waveforms.
Existing decoding circuit, the reception signal in half of data cycle can only be less than to the groove time and is decoded.
The content of the invention
Sent the technical problem to be solved in the present invention is to provide card reader in a kind of decoding agreements of ISO/IEC 14443
The decoder of TYPE a-signals, reception signal of the groove time less than half of data cycle can not only be decoded, moreover it is possible to during to groove
Between be more than half of data cycle reception signal decoded.
In order to solve the above technical problems, the TYPEA letters that card reader is sent in the decoding agreements of ISO/IEC 14443 of the present invention
Number decoder, including：
One counter, the counter reset during the groove of data waveform is received, and are receiving data waveform high level
Period counts；
One state machine, the state machine have 3 states, respectively X states, Y states, Z condition；The state machine it is initial
State is Z condition；The State Transferring of the state machine is by current state and the count value of counter and one group of threshold value ratio set
Compared with result determine；
One decode logic circuit, the status switch of decode logic circuit state machine according to receive process, solution
Code goes out the TYPEA signals of card reader transmission, including start of frame delimiter, data and frame end mark；
The control logic of the State Transferring of the state machine is as follows：
Under X states, if the count value of counter is more than first threshold, next state of state machine is exactly Y shapes
State, if instead the count value of counter is less than or equal to first threshold, next state is exactly X states；
Under Y states, if the count value of counter is more than the 3rd threshold value, next state of state machine is exactly Y shapes
State；If the count value of counter is less than or equal to the 3rd threshold value and is more than Second Threshold, next state is exactly X states；Such as
The count value of fruit counter is less than or equal to Second Threshold, then next state is exactly Z condition；
Under Z condition, if the count value of counter is more than the 5th threshold value, next state of state machine is exactly Y shapes
State；If the count value of counter is less than or equal to the 5th threshold value and is more than the 4th threshold value, next state is exactly X states, such as
The count value of fruit counter is less than or equal to the 4th threshold value, then next state is exactly Z condition.
The present invention realizes decoding using state machine, and three states of state machine correspond to X, tri- kinds of waveforms of Y, Z respectively.Due to
The first waveform that card reader is sent in the agreements of ISO/IEC 14443 is, it is known that so known to original state.The State Transferring of state machine
Determined by current state and the count value of a counter with the one group of threshold value set result of the comparison.The counter is recessed
Reset during groove, counted when receiving data waveform high level.Utilize the status switch in receive process of the state machine
With regard to groove signal can be decoded more than the TYPE a-signals that the card reader in half of data cycle is sent, including start of frame delimiter, number
According to this and frame end mark.
Brief description of the drawings
The present invention is further detailed explanation with embodiment below in conjunction with the accompanying drawings：
Fig. 1 is the X waveform diagrams of the TYPE a-signals that card reader is sent in ISO/IEC14443 agreements；
Fig. 2 is the Y waveform diagrams of the TYPE a-signals that card reader is sent in ISO/IEC14443 agreements；
Fig. 3 is the Z waveform diagrams of the TYPE a-signals that card reader is sent in ISO/IEC14443 agreements.
Fig. 4 is the logic diagram of the decoder for the TYPE a-signals that the decoding card reader is sent.
Embodiment
Assuming that the data cycle is T, the typical recess width that receives is W.Meanwhile a counter is realized, it is in the groove phase
Between clear 0, in X, Y, count at the high level of Z waveforms.
With reference to shown in Fig. 4, the operation principle of the decoder for the TYPE a-signals that the decoding card reader is sent is as follows：
It is X in known current form according to the coding rule in the agreements of ISO/IEC 14443, Y, in the case of Z waveforms,
To the waveform decoder immediately following it.It is described in detail as follows：
May be with X waveforms or Y waveforms after X waveforms.If be X waveforms, then between the groove of two X waveforms height electricity
Flat length is T-W, i.e. the count value of counter is T-W.If be Y waveforms, then because Y waveforms do not have groove, count
The count value of device is more than or equal to 1.5T-W.One threshold value is set in advance, is set to first threshold, the scope of first threshold is (T-
W)~(1.5T-W).If that the count value of counter is more than first threshold, be considered as be Y waveforms；, whereas if
The count value of counter is less than or equal to first threshold, be considered as be X waveforms.
May be with X waveforms, Y waveforms or Z waveforms after Y waveforms.Due to according to coding rule, the previous waveform one of Y waveforms
Surely it is X waveforms.The groove of so counter from that X waveform before Y waveforms begins to count from terminating.If after Y waveforms
Be X waveforms, counter is 2T-W；If Y waveform heels is Z waveforms, counter is 1.5T-W；
If Y waveform heels is Y waveforms, counter is more than or equal to 2.5T-W.Two threshold values are set in advance, are set to
Second Threshold and the 3rd threshold value.The scope of Second Threshold is (1.5T-W)~(2T-W)；The scope of 3rd threshold value is (2T-W)
~(2.5T-W).If the count value of counter is more than the 3rd threshold value, be considered as be Y waveforms；If the counting of counter
Value less than or equal to the 3rd threshold value and Second Threshold is more than, be considered as be X waveforms；If the count value of counter is less than or equal to
Second Threshold, be considered as be Z waveforms.
May be with X waveforms or Y waveforms after Z waveforms.If be X waveforms, then the count value of counter is 1.5T-
W；If be Y waveforms, then because Y waveforms do not have groove, the count value of counter is more than or equal to 2T-W；If with
It is Z waveforms, then the count value of counter is T-W.Two threshold values are set in advance, sets be designated as the 4th threshold value and the 5th threshold respectively
Value.The scope of 4th threshold value is (T-W)~(1.5T-W)；The scope of 5th threshold value is (1.5T-W)~(2T-W).If
The count value of counter is more than the 5th threshold value, be considered as be Y waveforms；If the count value of counter is less than or equal to the 5th threshold
Value and be more than the 4th threshold value, be considered as be X waveforms；If the count value of counter is less than or equal to the 4th threshold value, it is considered as
Be Z waveforms.
The above logic realizes that three states (X states, Y states, Z condition) of state machine have recorded by state machine
The waveform currently received, that is, the X waveforms received, Y waveforms, Z waveforms distinguish X states, Y states and Z-shaped in corresponding states machine
State.And according to coding rule, start of frame delimiter is Z waveforms, so the original state of state machine is Z condition.
Finally, using a decode logic circuit, decoded according to the status switch of state machine.According to coding rule, state
The original state Z of machine is decoded into start of frame delimiter；Immediately Y states are decoded for the continuous Y states of two of state machine or Z condition
Into frame end mark；In the case of other, the X states of state machine are decoded into logic 1, and the Y or Z condition of state machine, which are decoded into, to patrol
Collect 0.
The present invention is described in detail above by embodiment, but these are not formed to the present invention's
Limitation.Without departing from the principles of the present invention, those skilled in the art can also make many modification and improvement, these
It should be regarded as protection scope of the present invention.
Claims (2)
- A kind of 1. decoder for the type A signal that card reader is sent in decoding agreements of ISO/IEC 14443, it is characterised in that bag Include：One counter, the counter resets during the groove of data waveform is received, between data waveform high period is received Count；One state machine, the state machine have 3 states, respectively X states, Y states, Z condition；The original state of the state machine It is Z condition；The State Transferring of the state machine is by current state and the count value of counter compared with one group of threshold value set As a result determine；One decode logic circuit, the status switch of decode logic circuit state machine according to receive process, is decoded The type A signal that card reader is sent, including start of frame delimiter, data and frame end mark；The control logic of the State Transferring of the state machine is as follows：Under X states, if the count value of counter is more than first threshold, next state of state machine is exactly Y states, instead If the count value of counter be less than or equal to first threshold, next state is exactly X states；Under Y states, if the count value of counter is more than the 3rd threshold value, next state of state machine is exactly Y states；Such as The count value of fruit counter is less than or equal to the 3rd threshold value and is more than Second Threshold, then next state is exactly X states；If count The count value of device is less than or equal to Second Threshold, then next state is exactly Z condition；Under Z condition, if the count value of counter is more than the 5th threshold value, next state of state machine is exactly Y states；Such as The count value of fruit counter is less than or equal to the 5th threshold value and is more than the 4th threshold value, then next state is exactly X states, if counted The count value of device is less than or equal to the 4th threshold value, then next state is exactly Z condition.
- 2. decoder as described in claim 1, it is characterised in that：The input of the decode logic circuit is the shape of state machine State sequence, its decode logic are as follows：If the state of state machine is original state Z condition, start of frame delimiter is exported；If shape The state of state machine is two continuous Y states or Z condition immediately Y states, then exports frame end mark；If the state of state machine It is that X states then export 1,0 is exported if the state of state machine is Y states or Z condition.
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| CN103595420B true CN103595420B (en) | 2018-02-13 |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105224894B (en) * | 2014-05-28 | 2018-02-13 | 上海华虹集成电路有限责任公司 | Decode the circuit of the type A signal that card reader is sent in ISO/IEC14443 agreements |
| CN108958114B (en) * | 2018-07-12 | 2020-03-24 | 四川赛科安全技术有限公司 | Hardware coding and decoding method built in MCU for realizing industrial bus communication |
| CN109412757B (en) * | 2018-12-07 | 2021-01-22 | 上海爱信诺航芯电子科技有限公司 | Modified Miller self-adaptive decoding method and device |
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| JP3589092B2 (en) * | 1999-06-17 | 2004-11-17 | サクサ株式会社 | Non-contact IC card reader |
| CN1940972A (en) * | 2005-09-30 | 2007-04-04 | 富士通株式会社 | Noncontact tag, control method therefor and noncontact id identification system |
| CN201533303U (en) * | 2009-05-20 | 2010-07-21 | 上海华虹集成电路有限责任公司 | Improved Miler code encoding circuit |
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| US6962293B2 (en) * | 2002-09-26 | 2005-11-08 | Samsung Electronics Co., Ltd. | Circuit for generating clock signal and decoding data signal for use in contactless integrated circuit card |
| US8076970B2 (en) * | 2009-06-10 | 2011-12-13 | Infineon Technologies Ag | Adaptive demodulator |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3589092B2 (en) * | 1999-06-17 | 2004-11-17 | サクサ株式会社 | Non-contact IC card reader |
| CN1940972A (en) * | 2005-09-30 | 2007-04-04 | 富士通株式会社 | Noncontact tag, control method therefor and noncontact id identification system |
| CN201533303U (en) * | 2009-05-20 | 2010-07-21 | 上海华虹集成电路有限责任公司 | Improved Miler code encoding circuit |
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| 基于ISO/IEC 14443A协议的读卡器设计;张海鹏 和 王忠勇;《通信技术》;20091231;第42卷(第11期);全文 * |
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