WO2009030472A1 - Data communication according to the single wire protocol - Google Patents

Abstract

The invention relates to a method for data communication between a master (200) and a slave (300) according to the single wire protocol. At regular intervals that are longer than a master-to-slave bit transmission length, the master (200) sends clock pulse messages (500, 510, 520, 530, 540) to the slave (300). The slave (300) receives the clock pulse messages (500, 510, 520, 530, 540), recognizes them as clock pulse messages (500, 510, 520, 530, 540) and processes them. This allows the slave (300) to determine concrete intervals without a dedicated time measuring device, for example for determining timeouts. An NFC device (110) of a telecommunication terminal (100) can, for example, be provided as the master (200), a portable data carrier (10) as the slave (300), for example a SIM or USIM mobile communication card or a mass storage card.

Description

 Data communication according to the single-wire protocol

The present invention relates to a method for data communication between a master and a slave according to the single-wire protocol.

In a data communication that is carried out according to the so-called master-slave principle, a communication partner, the so-called master, controls the communication by sending commands to one or more other communication partners, so-called slaves. The slave responds to the commands of the master, but is in turn unable to initiate communication with the master itself. In addition, the master can control the slave e.g. supply power and provide this a clock signal.

Such a master may be, for example, an NFC device in a mobile terminal device which is used for contactless data transmission in the near range. A slave is then for example a SIM Mobufunkkarte, which is used in the mobile station and can communicate with the NFC device. The data communication between the NFC device as a master and the SIM mobile card as a slave can be performed, for example, according to the single-wire protocol. Also, a UICC ("Universal Integrated Circuit Card", often referred to as USIM mobile card), which takes on the role of the SIM mobile card in third generation mobile networks, or a mass storage card can take the role of the slave. The single-wire protocol (SWP) is based on a method which is described, for example, in WO 2006/043130 A1. Standardization of the single-wire protocol is underway (ISO / IEC JTC 1 N8018, 7 December 2005). The single-wire protocol enables data communication in duplex mode on just one transmission line. In addition, the slave on this line can be supplied with voltage by the master.

A data signal is transmitted from the master to the slave by modulating the width of a voltage pulse by a binary signal Sl (pulse width modulation). The width of the voltage pulse for transmitting a logical "1" is three times the width of the voltage pulse for transmitting a logic "0". Both voltage pulses have a duration which is in each case smaller than a fixed time period T, which is predetermined for transmitting one bit in each case. This period of time T is referred to as master-to-slave bit transmission duration in the context of the present invention. A data signal transmitted in this way implicitly carries clock information, since the voltage pulses always occur within a time interval of length T. The period T can thus be regarded as a clock signal, which is transmitted implicitly with the data signal from the master to the slave.

A data signal is transmitted from the slave to the master by the slave modulating the current drawn by the master according to a binary signal S2. A related current in a defined lower current range corresponds to a logical "0", a current referred to in a defined upper current range of a logical "1". In this way, data from the master can be simultaneously transmitted via the same line Slave by modulation of the voltage pulse width and transmitted from the slave to the master by current modulation.

The single-wire protocol has four states for the data communication connection established via the transmission line: "active", "suspend", "resume" and "reset". In the active state ("active state"), data is transferred between the master and the slave. If no electrical activity is detected over a certain period of time, the master places the data communication connection in the "suspend state". During the standby state, there is usually a constant, non-pulsed voltage on the transmission line. In the standby state, therefore, no implicit clock signal is transmitted. Both the master and the slave can put the data communication connection from the ready state back to the active state ("resume state"). The master sends a data frame on the transmission line to the slave, the slave sends a logical "1" to the master. The master can reset the slave at any time ("reset state") by applying no voltage to the line for a certain period of time.

The clock signal transmitted from the master along with the data signal is generally not used by the slave to decode received data. Instead, the slave has its own clock generator whose clock is between T / 8 and T / 128. This clock is used by the slave in particular for decoding received data. For this purpose, the number of clocks of the clock signal generated by the clock generator is counted, which occur while the input signal is applied as a logic "0" and compared with the corresponding number of clocks, which are counted while the input signal Sl is applied as a logical "1". Depending on whether this difference is positive or negative, the input signal can be undoubtedly decoded to "0" or "1".

The slave requires a device to determine specific time periods, for example, to enable a correct transmission of timeout messages, so-called "timeouts". The clock signal implicitly transmitted with the data signal can only be used to a limited extent by the slave for timing purposes, in particular also because this clock signal is not transmitted continuously by the master, but only during the active state, but not during the standby state. Time-out messages serve as part of a data communication to prevent an unlimited waiting for possibly lost messages that are embedded in special data frames embedded in the single-wire protocol. To ensure correct data transfer between the master and the slave, each data frame sent carries a number. Receipt of a correct data frame by the receiver is acknowledged by the receiver by the receiver with an acknowledgment (in the form of a special data frame) with a corresponding number. It is possible that data frames and / or receipts may be damaged or lost during data transfer. To detect and resolve this, the single-wire protocol provides a time-tracking mechanism. This specifies that a data frame that has not been acknowledged as having arrived correctly after a set period of time is sent again. In order to support this time monitoring mechanism, the slave thus needs a device to determine specific time periods. The slave has hardware components that allow it to "calculate" time periods based on the clock generated by its own clock generator. Such calculations are expensive and consume resources of the slave. Furthermore are the calculated periods of time quite inaccurate. Therefore, only an approximate time allocation between master and slave can be established.

It is therefore the object of the present invention to propose a method which, in the context of a data communication with a master according to the single-wire protocol, allows a slave to determine specific time periods, e.g. for determining timeouts.

This object is achieved by two methods, a data processing device and a data carrier having the features of the independent claims. Advantageous embodiments and further developments are specified in the dependent claims.

According to the invention, the master sends clock messages to the slave as part of a data communication in accordance with the single-wire protocol. The master sends these timing messages at intervals greater than the master-to-slave bit transmission time. On the other hand, the slave receives these timing messages, recognizes them as timing messages, and processes them. Accordingly, a data processing device according to the invention, which is set up as a master to send messages according to the single-wire protocol to a slave, comprises a timing device which is set up to transmit the timing messages in the manner described above. A portable data carrier according to the invention, which is set up to receive messages from a data processing device in accordance with the single-wire protocol, comprises a time-clock detection device which is set up to receive the time-clock messages described and to recognize and process them as such. In this way, a temporal association between the master and the slave is established. The timing messages allow the slave to specify specific time periods. A separate timing device in the slave is not required. The approximate time span calculation by means of the clock generated by the slave's own clock generator is replaced by an exact time span determination by means of the clock signals. The hardware components and other resources previously used in the data medium for the approximate time span calculation, such as computing time, can be used or saved for other purposes.

The timing messages are different from ordinary data messages implicitly containing timing information as mentioned above, particularly in that the timing messages are transmitted at intervals greater than a master-to-slave bit transmission duration of a data signal corresponding to the data message transmitted from the master to the master Slave is transmitted. In the context of the present invention, a distinction is made between a message to be transmitted and the signal to be transmitted for transmitting the message, that is to say the physical appearance of the message.

The data processing device can be, for example, an NFC device of a telecommunications terminal, e.g. a Mobilfunkendge- device, a handheld or the like. The data carrier may be a SIM or USIM mobile card, a mass storage card or the like.

For example, the volume uses the timing messages to determine a specific time-out period. In this way, the data communication between the master and the slave is carried out more effectively. ftihrt. Communication errors or waiting times due to incorrect timing are eliminated. Thus, for example, it does not occur that a data frame is sent again too early by the slave, that is to say before the time span defined for this in the single-wire protocol has expired, which would result in a communication error at the master. Likewise, it is avoided that a necessary transmission of a data frame takes place too late, which would result in unnecessary waiting times.

The time clock device of the data processing device sends the time clock messages to the data carrier at regular intervals. The timing messages serve the time clock detection means of the disk as a regular time clock and help the disk to its own regularly timed timing.

Advantageously, the time clock device of the data processing device transmits time clock messages both in the active state and in the standby state. Likewise, the clocking means of the data carrier is arranged to receive timing messages in both the active state and the standby state, to recognize and process them as timing messages. In this way, during the entire time that the data communication connection between the data processing device and the data carrier exists, the data carrier has a possibility of determining the time span.

Time-clock messages sent by the time-clock device of the data processing device can be embodied in different ways, wherein the time-clock recognition device of the data carrier is in each case set up to recognize the differently formed time-clock messages as time-clock messages. In the active state, clock messages sent by the master can be sent, for example, in the form of so-called "flags". It should be noted that a data frame according to the single-wire protocol is framed by special separators, each comprising eight bits. The so-called start-of-frame-delimiter ("SOF flag", "start-of-frame flag") has the hexadecimal name OxTE and is always at the beginning of a data frame. The so-called end-of-frame flag ("EOF flag") has the hexadecimal value 0xFE and is always at the end of a data frame. Between these frame delimiter separators are various data blocks. Some of them are for tax purposes, eg contain address information, data frame type information or check digits, another block contains the messages to be transmitted.

According to a first embodiment, a new delimiter is defined which differs from the SOF flag and the EOF flag and serves only as a clock message, for example the eight-bit separator with the hexadecimal value 0xFF. Such a delimiter defined solely for the purpose of forming a time tracking can be quickly recognized by the time-clock recognition device since an evaluation of ordinary data frames is not necessary for this purpose and it can already be recognized after eight bits received.

According to a second embodiment, it is provided that the time clock device of the data processing device sends an empty data frame as a time-clock message. An empty data frame does not include any further data blocks apart from the SOF flag and the directly following EOF flag. Such a timing message is also dependent on the time clock recognition device. tion of the data carrier quickly and easily. This time-clock message also has the advantage that no new delimiter must be defined. This also applies to the third embodiment described below.

According to the third embodiment, the clock means sends as a clock message an isolated EOF flag between two transmitted frames. Such a timing message can also be easily recognized by the time-clock recognizer, since an EOF flag following an EOF flag without an SOF flag being sent therebetween can easily be recognized as such. It is also possible that the timing device sends several EOF flags one after the other without transmitting a common data frame in between.

In the context of this third embodiment, it is also possible for the time clock device of the data processing device to alternatively or additionally use a SOF flag as the clock signal and to send it embedded in an ordinary data frame. For the time clock recognition device of the data carrier, such an SOF flag is to be recognized as a time-clock message, since the data frame in which a time-clock message formed in this way is embedded is opened by an SOF flag, but has not yet been terminated by an EOF flag. It is again possible to embed several SOF flags as time clock messages in a data frame.

The clock messages sent by the master in the standby state can also be designed differently. Preferably, a standby clock in the standby state comprises at least one bit and less than eight bits, whereby a confusion with an eight-bit delimiter, which opens a new data frame, is excluded. Vorzugswei- That is, after the sending of a timing message by the clocking means of the data processing device, the standby state is maintained. In this way, the time clock recognition device of the data carrier is also given the opportunity to determine specific time periods when no clock signal is transmitted implicitly with a data signal from the master to the slave.

The clock detection means of the data carrier may change a defined register as a result of processing the timing messages. In this way, the processing can be done quickly and this result can be accessed quickly and effectively to determine specific time periods based on the timing messages. The register can, for example, be toggled in each case after receiving a time-clock message, that is, switched back and forth between two states. It is also possible to increment or decrement the register after each received clock message. A overflow or underflow of the register resulting from this variant, possibly after some time, is preferably signaled to the time clock recognition device by a corresponding interruption. The time clock recognition device then reinitiates the register in order to be able to correctly process subsequently received time clock messages.

An inventive system accordingly comprises a data processing device described above and a data carrier described above, which are set up to carry out the method described above. Such a system comprises, for example, a telecommunication terminal with an NFC device, which is set up with a data carrier used in the telecommunication terminal, eg a SIM or USIM cellular card or a mass storage card to communicate in accordance with the single-wire protocol.

The present invention will be described by way of example with reference to the accompanying drawings. Show:

Figure 1 shows a preferred embodiment of an inventive

Data carrier;

Figure 2 shows a preferred embodiment of a system according to the invention, comprising a telecommunication terminal with an NFC device and the data carrier of Fig. 1;

FIG. 3 shows a schematic representation of a first preferred embodiment of a first embodiment of the method according to the invention;

Figure 4 is a schematic representation of a second preferred embodiment of the first embodiment of the inventive method;

Figure 5A is a schematic representation of a first variant of a third preferred embodiment of the first embodiment of the method according to the invention;

Figure 5B is a schematic representation of a second variant of the third preferred embodiment of the first embodiment of the method according to the invention; and Figure 6 is a schematic representation of a preferred embodiment of a second embodiment of the method according to the invention, which can be combined with the Ausführungsfoπnen of Figures 3 to 5B of the first embodiment.

With reference to FIG. 1, a portable data carrier 10 embodied as a SIM mobile radio card in this specific embodiment comprises a data communication interface 20 for contact-type data communication with a data processing device. The data communication interface 20 is designed as a contact field in accordance with ISO / IEC 7816 and comprises eight contacts C1 to C8. Other contact data communication interfaces are possible, for example a USB interface. The volume 10 may also be a USIM mobile card or a mass storage card, e.g. an SD card ("Secure Digital Memory Card"), which comprises a data communication interface 20 designed according to the SD specification.

The SIM mobile communication card 10 further includes a processor (CPU) 30, a non-volatile, non-rewritable ROM 40, a non-volatile rewritable FLASH memory 50 and a volatile random access memory (RAM) 60. In the ROM 40 is a Operating system (OS) 42 of the SIM mobile card 10 is stored. The FLASH memory 50 is used to store applications and data. It contains an application described in detail below with reference to FIGS. 3 to 6, which implements a time-clock recognition device 52. Furthermore, the memory 50 contains a file system and applications (not shown) of a typical SIM mobile communication card, for example applications for authenticating the user to a mobile radio network. The memory 50 may also be designed as an EEPROM memory or the like. FIG. 2 shows a telecommunications terminal 100 in the form of a mobile radio terminal. It comprises a processor (CPU) 180, which on the one hand is connected to an NFC device 110 and on the other hand to a reading device 160 for receiving a SIM mobile communication card. The NFC device 110 is connected to the reading device 160 via a connecting line 155 and is configured to communicate directly, ie without a detour via the processor 180, with the SIM mobile radio card 10 received by the reading device 160 in accordance with the single-wire protocol.

The NFC device 110 comprises an antenna 120 and a modem 130, which serve for contactless data transmission in the near range. Via the antenna 120, the NFC device 110 can also draw energy from an electromagnetic field. A control device 150 for controlling the NFC device 110 comprises a timing device 152 described in more detail below with reference to FIGS. 3 to 6.

As already mentioned, the reading device 160 serves for receiving the SIM mobile communication card 10 from FIG. 1 and therefore comprises a suitable interface which interacts with the contact surface 20 of the SIM mobile communication card 10. The NFC device 110 is connected via the interface with the SIM mobile card 10 via the connection line 155 and the reading device 160. The physical connection produced in this way uses the contact C6 of the contact surface 20 on the SIM mobile card 10 side, which is not yet occupied by other applications of the SIM mobile radio card 10. If, instead of the SIM mobile communication card 10, another data carrier is used in order to be connected to the NFC device 110, then a reading device is used which is correspondingly adapted to this data carrier and its data communication interface. It is possible that the mobile terminal 100 comprises a plurality of different reading devices and thereby can accommodate a plurality of different data carriers, which can then each communicate with the NFC device 110.

The NFC device 110 and the SIM mobile calling card 10 are set up to establish a data communication connection with each other via the connection line 155 in accordance with the single-wire protocol (SWP) and to send messages to the respective communication partner. The NFC device 110 assumes the role of the master, the SIM mobile radio card 10 the role of the slave. The SIM Mobufunkkarte 10 can be powered by the NFC device 110 via the connecting line 155 with energy. Thus, data communication is possible even if the NFC device 110 is in an electromagnetic field, but the mobile station 100 is switched off, via which the SIM mobile radio card otherwise derives its energy. If the data communication connection established between the NFC device 110 and the SIM mobile memory card 10 is in the so-called active state, then the NFC device 110 transmits a signal S1 to the SIM mobile radio card 10 in accordance with the single-wire protocol by pulse width modulation of voltage - impulses. The SIM Mobufunkkarte 10 in turn transmits in the active state of the Datenkommurύkationsverbindung in accordance with the single-wire protocol, a signal S2 to the NFC device 110 by modulating a related via the connection line 155 amperage.

The signal Sl implicitly carries a clock signal which describes a period T. T denotes a master-to-slave bit transmission duration, that is, a fixed time period which is intended to transmit a bit, "0" or "1", from the master to the slave. However, the implicit clock signal transmitted from the NFC device 110 to the SIM mobile radio card 10 is handled by the SIM mobile card 10 is generally not used to decode the signal Sl. For this purpose, and for synchronizing the signal S2 to the signal Sl, the SIM mobile communication card 10 has its own clock generator and a decoder (not shown). On the other hand, if the data communication connection established between the NFC device 110 and the SIM mobile communications card 10 is in the so-called standby state, a constant, non-pulsed voltage is applied to the connection line 155. In the standby state, therefore, no implicit clock signal is transmitted from the master to the slave.

In the context of the present invention, a data communication connection described above can be set up between any data processing device instead of the NFC device 110 and any portable data carrier instead of the SIM mobile communication card 10, as long as the data processing device and the data carrier with the components described above and suitably set up are equipped. The invention will be described below by way of example using the example of the NFC device 110 and the SIM mobile communication card 10.

As illustrated with reference to FIGS. 3 to 6, the clock means 152 of the NFC device 110 is set up as part of the data communication according to the single-wire protocol between the NFC device 110 as master 200 and the SIM mobile communication card 10 as slave 300 time clock messages 500, 510, 520, 530, 540 to the SIM mobile card 10 sen. These time-clock messages 500, 510, 520, 530, 540 are received by the time-clock recognition device 52 of the SIM mobile radio card 10, recognized and processed as time-clock messages 500, 510, 520, 530, 540. With the help of the clock messages 500, 510, 520, 530, 540, a temporal association between the NFC device 110 and the SIM mobile communication card 10 is established. The time clock device 152 of the NFC device 110 transmits the clock messages 500, 510, 520, 530, 540 at regular time intervals. For this purpose, the time clock device 152 in turn has a suitable time measuring device (not shown) or receives timing information from the outside, for example from the processor 180 of the mobile terminal 100 or via the antenna 120. It is possible, the time intervals in which the clock device 152 clock messages 500, 510, 520, 530, 540 transmits, for example, to adapt to different data carriers that can be used in the mobile device 100. However, the time intervals in each case describe a separate from the master-to-slave bit transmission time period, which accordingly exceeds the master-to-slave bit transmission time in particular.

The time clock recognition device 52 of the SIM mobile card 10 uses the timing messages 500, 510, 520, 530, 540 for determining specific time periods, in particular for the correct determination of timeouts. For this purpose, the time-clock recognition device 52 processes the time-clock messages 500, 510, 520, 530, 540 received at regular intervals by, after receiving and recognizing such a time-clock message 500, 510, 520, 530, 540, reserving a register (not shown) for this purpose ) is incremented (or decremented). The register is properly initialized at the beginning of the data communication. The value of the register indicates the number of received clock messages directly (or indirectly). Thus, the timing detection means 52 may determine the elapsed time between any two received timing messages 500, 510, 520, 530, 540 by recording the difference of the register entries at the time of receiving the respective timing messages 500, 510, 520, 530, 540 the time interval between two successive clock messages 500, 510, 520, 530, 540 multiplied. An overflow (or underflow) of the register is handled by a corresponding interrupt routine and the register is reinitialized. Also, a switchable register may be used to process the timing messages 500, 510, 520, 530, 540 by toggling the register.

The clock means 152 of the NFC device 110 sends according to a first embodiment time clock messages 500, 510, 520 or 530 to the SIM mobile card 10, while the established data communication connection is in the active state (Figures 3, 4, 5 A, 5B). According to a second embodiment, which can be combined with the first embodiment, the time clock device 152 also transmits time-clock messages 540 to the SIM mobile communication card during the standby state (FIG. 6). In this way, it is ensured that the SIM mobile communication card 10 is able to determine specific time periods during the entire duration of the data communication with the NFC device 110. Accordingly, the time clock recognition device 52 of the SIM mobile card 10 is set up to receive, recognize and process the clock messages 500, 510, 520, 530, 540 both in the active state and in the standby state.

The shape of the data blocks forming the different timing clock messages 500, 510, 520, 530, 540 will be explained in more detail below. The timing messages 500, 510, 520, 530, 540 are always messages sent in addition to or integrated with ordinary data messages separately. The temporal information transmitted by the clock clocks 500, 510, 520, 530, 540 is therefore not only implicitly part of a data signal, but is explicitly represented in the form of a message. ordinary Data messages are sent as data frame 400. A data frame 400 begins with a start-of-data frame delimiter SOF and ends with an end-of-frame delimiter EOF. These two separators are usually eight bits long, with SOF having the hexadecimal value 0x7E (binary: Olli 1110) and EOF of the hexadecimal value OxFE (binary: 1111 1110).

According to a first embodiment shown in FIG. 3, a new eight-bit delimiter is specifically defined for the purpose of forming the time-clock message 500. The delimiter has the hexadecimal value 0xFF (binary: 1111 1111) and is sent to the SIM mobile radio card 10 by the clock device 152 of the NFC device 110 between transmitted data frames 400. It is also possible to send multiple clock messages 500 without a data frame 400 being sent therebetween.

With reference to FIG. 4, according to a second embodiment, an empty data frame is sent as a clock message 510 from the master 200 to the slave 300, that is, from the NFC device 110 to the SIM mobile card 10. The empty data frame 510 comprises only an SOF and a direct following EOF, thus has (binary) the value Olli 1110 1111 1110. Also in this embodiment, the timing messages 510 may be sent between ordinary data frames 400 or sequentially, i. without sending a common data frame 400 in between.

According to a third embodiment illustrated in FIGS. 5A and 5B, SOF and EOF are themselves sent as timing messages 520, 530 from the master 200. For this purpose, in a first variant EOF is recognized by the slave 300 as a clock signal 520 if it is after a previously sent EOF (for example, at the end of a data frame 400 as in Figure 5A) or a directly previously sent clock message 520 is sent in the same form without a SOF has been sent in between. According to a second variant illustrated in FIG. 5B, SOF is recognized by the slave 300 as a timing message 530 when it is sent from the master 200 to a common data frame 400. It is also possible in this second variant that a plurality of clock messages 530 in the form SOF are embedded in the same data frame 400.

With reference to Figure 6, an embodiment of the second embodiment of the method is shown. The master 200, in the standby state in which no data messages in the form of data frames 400 are sent to the slave 300, sends clock messages 540 in the form of two-bit data blocks having the binary value 11 to the slave 300. The length and value of the Clock messages 540 serving data blocks is variable. The length can vary between one bit and seven bits. The value of the respective bits is also variable.

Claims

Patent claims A method for data communication between a master (200) and a slave (300) according to the single-wire protocol, characterized in that the master (200) at intervals, which are greater than a master-to-slave bit transmission time Sends timing messages (500, 510, 520, 530, 540) to the slave (300) which allow the slave (300) to determine a time span using the time interval known to the slave. 2. The method according to claim 1, characterized in that the master (200) in each case after expiry of the time interval, the next time-clock message (500) sends. 3. The method according to claim 1 or 2, characterized in that the master (200) as the timing message (500) sends a time stamp defined as a separator, wherein preferably the defined separator is selected such that it has the hexadecimal value of 0xFF. 4. The method according to claim 1 or 2, characterized in that the master (200) as a timing message (520) sends an end-of-data frame delimiter (EOF) between two transmitted data frames (400). 5. The method of claim 1, 2 or 4, characterized in that the master (200) as the timing message (530) sends a beginning of the data frame delimiter (SOF) within a transmitted data frame (400). 6. The method according to claim 1 or 2, characterized in that the master (200) as a timing message (510) sends an empty data frame. 7. The method according to any one of claims 1 to 6, characterized marked, that the master (200) sends clock messages (540) in the standby state. A method according to claim 7, characterized in that the master (200) transmits, as a clock message (540), a message comprising at least one bit and less than eight bits, and / or maintaining the ready state after sending the clock message (540) becomes. 9. A method for data communication between a master (200) and a slave (300) according to the single-wire protocol, characterized in that the slave (300) from the master (200) at intervals that are greater than receives a master-to-slave bit transmission time, transmitted timing messages (500, 510, 520, 530, 540), which allow the slave (300) a period of time from the known time interval of the timing messages (500, 510, 520, 530 , 540), and recognize and process them as timing messages (500, 510, 520, 530, 540). 10. The method according to claim 9, characterized in that the slave (300) from the number of received clock messages and the known time interval of the clock messages (500, 510, 520, 530, 540) determines the period of time. The method of claim 9 or 10, characterized in that the slave (300) uses the timing messages (500, 510, 520, 530, 540) to determine timeout periods. A method according to claim 10 or 11, characterized in that the slave (300) changes a defined register as a result of processing the timing messages (500, 510, 520, 530, 540), preferably the register either at each received timing message ( 500, 510, 520, 530, 540) is toggled or incremented or decremented at each received timing message (500, 510, 520, 530, 540). 13. A data processing device (110) which is set up as a master (200) to send messages according to the single-wire protocol to a slave (300), characterized by a timing device (152) which is set up at intervals, the is greater than a master-to-slave bit transfer time to send timing messages (500, 510, 520, 530, 540) to the slave (300). 14. Portable data carrier (10), which is configured as a slave (300) to receive messages according to the single-wire protocol (ETSI TS 102613) from a master (200), characterized by a time-clock detection device (52) is arranged to receive from the master (200), at time intervals greater than a master-to-slave bit transmission duration, time-of-clock messages (500, 510, 520, 530, 540) as clock messages (500, 510 520, 530, 540) to recognize and process. 15. System comprising a data processing device (110) according to claim 13 and a portable data carrier (10) according to claim 14, wherein the data processing device is set up to execute the steps of the master from a method according to claims 1 to 8 and the portable data carrier (10) is set up to carry out the steps of the slave according to one of claims 9 to 13.