EP1766589B1 - Method for managing a plurality of electronic chip token readers and equipment units for carrying out said method - Google Patents

Description

The present invention relates generally to the field of chips incorporating an electronic chip and contactless radiofrequency readers of these chip tokens, these readers, also RFID reader (Radiofrequency Identification), being able to work in reading and / or in writing.

More particularly, but without limitation, the invention finds its application in the field of casinos or gaming rooms for the management of a large fleet of gambling chips, also called casino chips, these being distributed between the bank The use of contactless radiofrequency readers communicating with chip chips facilitates the work of the casino operator, particularly for the detection of fraudulent tokens, the location and location of the casino. the tracking of chips in the casino, the counting of chips in number and value, the monitoring of transactions at tables of exchange or game, etc ...

For the rest of the discussion, a game token is any disc or plate-shaped element most often made of rigid plastic material. The tokens have various patterns in designs and colors to form a more or less complex decor and reduce the risk of forgery and / or fraudulent reproduction. Some tokens incorporate an electronic memory circuit, or electronic chip, in which information about the token is stored, including its serial number or identification code and its numerical value. These tokens equipped with electronic memory circuits are also referred to as electronic chip tokens or electronic memory tokens. According to the models of the tokens, the electronic circuits are of the PROM single read-only type, reprogrammable EEPROM memory with readability and / or write capability or even microprocessors with a memory. Finally, the electronic circuits of the chips or electronic circuits comprise a winding used to make a radio frequency transponder without contact and to communicate by magnetic coupling with the antennas of the radio frequency readers, the electric field radiated by the antennas of the readers being also used to generate the energy electric necessary for fleas. In practice, the communication of the information-carrying signals is done by modulation / demodulation of a pre-established frequency carrier wave, by way of non-limiting example of 125 KHz.

For the remainder of the talk, we also mean the term reader in its widest sense as a device allowing in particular the reading of the memory of the chip and / or the writing in memory and without any limiting character, each reader is associated with a microprocessor control unit so as to issue commands and data to a chip in the corresponding antenna field and to receive and process the responses therefrom, some readers being able to control in turn several antennas. In practice, a central reader control unit that manages a plurality of readers is used.

Interest in casinos' introduction of Chip Tokens drives operators to multiply their numbers and reduce the distance between corresponding antennas to two separate readers. This results in risks of disturbances in communications between chips and readers all the more troublesome in terms of reception to the readers, the signal intensity emitted by the winding of the chip being much lower than the signal strength emitted by the antenna of a reader. Thus the reception by a reader can be seriously disturbed by the simultaneous emission of the antenna of a nearby reader too close. This unsatisfactory situation occurs when several readers are mounted close enough to each other, for example on the exchange tables or on the same game table, such as a roulette table or blackjack where the distance between antennas can go down up to 30cm. The solution consisting in equipping the concerned tables with electromagnetic shielding around the antennas is inconvenient or difficult to implement, often for lack of space, and does not seem very effective in the end.

The document US-5,646,607 discloses an identification system using transponders and interrogation devices, the identification system for identifying the position or presence of the transponders in a defined area. The system implements in particular synchronization means interrogation devices, so that they transmit their transmission information exactly simultaneously.

Although limiting interferences in transmissions between the interrogation devices and the transponders, this system is not effective for processing transmission operations whose durations are all different, such a system being based on a predetermined time interval for transmit the information.

The purpose of the invention is to propose a method of managing a plurality of contactless radiofrequency readers of Tokens making it possible to eliminate disturbances between readers due to disordered transmission / reception operations, in particular by close-up antennas, or at least to reduce very significantly the effects on the communications go and / or return between readers and chips.

To this end, the invention proposes a method of coordinating management of a plurality of contactless radio-frequency chip readers in accordance with claim 1.

Thus, the synchronization of the Tx / Rx cycles by separate grouping of the transmission operations Tx on one side and the reception operations Rx on the other hand makes it possible to make several parallel antenna readers work simultaneously, the final time saving for the processing a batch of chips shared between Nx active readers simultaneously compared to a treatment of this batch by a single reader or the Nx readers but work successively to avoid the aforementioned disturbances being much greater than the delay introduced by the process synchronization. It should be noted that the readers concerned by the synchronization process are the only Nx readers then active of the plurality of NL readers, and for which a TxMx cycle is pending, without prejudice to any generalization or assimilation of others. readers of the plurality if necessary, for example non-limiting as will appear below in the case of cuts and restoration of antenna currents.

On the other hand, the grouping makes it possible to minimize the time interval necessary for the Tx transmissions thus grouped (in this case the longest transmission time Tx) and to start the reception operations Rx immediately after the instant Tx transmissions are terminated so as to also reduce the time interval required for the Rx receptions thus grouped to the longest reception time.

• une étape de collecte des durées TxL des transmissions Tx des instructions de commande des premiers cycles Tx/Rx en attente des lecteurs actifs (certaines protocoles de commandes pouvant prendre la forme d'une suite de plusieurs cycles Tx/Rx), et
• une étape d'émission d'ordres d'exécution aux lecteurs actifs des transmissions Tx des instructions de commande des cycles Tx/Rx échelonnés dans le temps et ordonnés selon les durées TxL décroissantes en commençant par le lecteur auquel est affectée l'instruction de commande du cycle Tx/Rx ayant la plus grande durée TxL, le délai entre un ordre d'exécution et son suivant étant égal à la différence des durées TxL des instructions de commande des cycles Tx/Rx à transmettre par les deux lecteurs correspondants, ceci jusqu'à l'ordre d'exécution associé à la plus courte durée TxL.

According to a first advantageous variant of the method according to the invention, the synchronization process comprises:

• a step of collecting the TxL durations of the Tx transmissions of the instructions for controlling the first Tx / Rx cycles waiting for the active readers (certain control protocols may take the form of a series of several Tx / Rx cycles), and
• a step of issuing execution orders to the active readers of the Tx transmissions of the instructions for controlling the Tx / Rx cycles staggered in time and ordered according to the decreasing times TxL starting with the reader to which the command instruction is assigned of the cycle Tx / Rx having the greatest duration TxL, the delay between an execution order and its next being equal to the difference of the durations TxL of the command instructions of the cycles Tx / Rx to be transmitted by the two corresponding readers, this up to 'to the execution order associated with the shortest duration TxL.

Such a structured process can be implemented by hardware and / or software solutions as will appear in more detail hereinafter.

Moreover, for reasons of energy saving and / or of putting the chips of the chips placed in the field of an antenna of a reader back into the standby state, it is desirable or necessary to cut the current of this antenna. These cuts and restoration of antenna current can cause disturbances, especially at Rx receptions as long as the antenna current is not stabilized. An advantageous solution to this problem is provided by the following variant of the method according to the invention.

• ces instructions CA à des instructions de commande d'un cycle Tx/Rx vers un lecteur actif,
• la durée de la stabilisation du courant d'antenne suite à l'exécution d'une instruction CA à la durée TxL de transmission Tx de l'instruction de commande d'un cycle Tx/Rx au lecteur actif, ladite durée de stabilisation étant appelée ci-après durée TxL assimilée et l'instruction CA étant également appelée ci-après transmission Tx assimilée, et
• un ordre d'exécution d'une commande CA à un ordre d'exécution d'une transmission Tx d'un cycle Tx/Rx dans lequel la durée de l'opération Rx est nulle, ci-après appelé cycle Tx/Rx assimilé, le lecteur concerné par une commande CA étant alors assimilé à un lecteur actif.

According to another optional but advantageous variant of the method according to the invention, the synchronization process integrates the synchronization of the instructions for establishing and / or breaking AC of the antenna current of one or more readers of said plurality of readers by assimilating:

• these CA statements to instructions to control a Tx / Rx cycle to an active drive,
• the duration of the stabilization of the antenna current following the execution of an instruction CA with the duration TxL of transmission Tx of the instruction command of a cycle Tx / Rx to the active reader, said stabilization duration being called hereinafter duration TxL assimilated and the instruction CA being also called hereinafter transmission Tx assimilated, and
• an order of execution of a command CA to an order of execution of a transmission Tx of a cycle Tx / Rx in which the duration of the operation Rx is zero, hereinafter called Tx / Rx cycle assimilated, the reader concerned by a command CA being then assimilated to an active reader.

This variant makes it possible, on the one hand, to eliminate the disturbances caused by the cuts and recovery of antenna current and, on the other hand, to obtain this elimination without hindering the coordinated management of the plurality of readers and at a lower cost in material resources. and software.

To further improve the synchronism between readers, the TxL times, real and / or assimilated, are in the form of multiples of the period of the carrier wave used by the readers.

Advantageously, the synchronization process is implemented by a synchronization circuit according to a synchronization cycle CS initiated either by the first request for authorization to execute a real Tx / Rx cycle or similar, made by a reader as a result a request from a central control unit of the reader, either automatically at the end of the last Rx reception operation of the real Tx / Rx cycles corresponding to the previous CS synchronization cycle or to the actual Tx / Rx cycle failure at the end of transmission operations Tx assimilated.

This procedure of the method according to the invention makes it possible to actually involve in the synchronization process only the Nx readers actually active (having a Tx / Rx cycle pending) of the plurality NL of readers in coordinated management.

Advantageously, participate in a new CS synchronization cycle all the readers having transmitted requests for authorization of execution of a real Tx / Rx cycle or assimilated since the beginning of execution of the previous CS synchronization cycle.

This operating mode of the method according to the invention makes it possible to limit the waiting of the execution orders of the transmissions Tx of the active readers.

Advantageously also participate in the new CS synchronization cycle all active readers who participated in the previous synchronization cycle.

This procedure of the method according to the invention makes it possible to automatically process the series or series of several Tx / Rx cycles for the same reader without risk of interruption.

Advantageously for each synchronization cycle CS, the step of collecting the times TxL, real and / or assimilated, is carried out for all the NL readers of the plurality of readers with determination of the number Nx of readers for which an order of execution of the transmission Tx, real or assimilated, will have to be issued and in that the step of transmitting transmission execution orders Tx is adapted as a function of Nx.

This operating mode of the method according to the invention allows a saving of time in the execution of the synchronization cycle.

According to another optional but advantageous variant of the method according to the invention the clock signals of each reader of the plurality of readers are synchronized from the same time base.

This operating mode allows the readers to generate synchronized carrier waves at the chosen frequency, in this case, by way of non-limiting example, at 125 KHz.

• détermination, à l'occasion de la détection d'une collision par discordance entre la valeur 0 ou 1 d'un bit de la réponse par rapport à la valeur attendue pour ce même bit, d'un degré « fort » ou « faible » de la collision en fonction du niveau d'incertitude sur la valeur détectée du bit de réponse concerné;
• traitement des collisions par itération avec pour la première itération le seul traitement des collisions à degré « fort».

According to yet another advantageous variant of the method according to the invention in a version where it is intended to be used with readers having a function of detection and management of collisions at the level of the simultaneous responses of several chips to the same control command. a Tx / Rx cycle, the method is characterized that it is associated with means adapted to implement the accelerated collision management process according to:

• determining, on the occasion of the detection of a discrepancy collision between the value 0 or 1 of a bit of the response with respect to the value expected for the same bit, of a "strong" or "weak" degree the collision as a function of the level of uncertainty on the detected value of the response bit concerned;
• collision processing by iteration with for the first iteration the only treatment of "strong" collisions.

This procedure makes it possible to process during the first iteration of the method only the collisions with "strong" degree (for which the uncertainty is low) and which in practice corresponds to the true collisions (for example reading by the reader of an answer to a request for identification of a given serial number token, stored in its own chip, by the chip of another token carrying a neighboring serial number), the false collisions (generally resulting from the difficulty, and therefore of a high level of uncertainty, to read the value of the bit concerned in the response) being then eliminated from the processing of the first iteration. By way of nonlimiting example, the processing may consist in obtaining confirmation by targeted interrogation of certain serial number fields of the number of the token originating from the answer, even if it eliminates the incriminated token by rendering it "silent" (inhibition of operation Rx), if it is not one of the wanted tokens. This operating mode makes it possible to very substantially accelerate the management of true collisions and the playing and / or writing times of the chips. It should be noted that each false collision unnecessarily increases the reading time due to attempts to discover SNR serial numbers which in reality do not exist, hence the need to avoid such collisions.

Advantageously, the discrimination between the "strong" and "low" degrees of the collisions is obtained by fixing for each reader a predetermined sharing threshold associated with the level of uncertainty on the detected value of the response bit concerned.

This mode of operation makes it possible to adapt the sharing threshold to each reader and to his immediate environment (distance between reader antennas, forms and / or arrangement of the antennas, real power dissipated, etc.).

Advantageously, the sharing threshold is chosen so as to distinguish the true collisions, collisions of "strong" degree, resulting from the simultaneous responses of several separate chips, false collisions, collisions of "weak" degree resulting in particular from electromagnetic disturbances external to the readers or disturbances between antenna readers in close proximity during the transmission of Rx responses.

The invention also relates to a synchronization circuit for a plurality of non-contact token electronic chip readers for implementing the method according to the invention presented above in all its variants, the circuit comprising a processing unit. microprocessor-based device adapted to perform the execution of the synchronization process, the processing unit being associated with an interface circuit intended to be suitably connected with each of the readers of said plurality of readers. For this purpose the processing unit has the hardware and software means to perform the execution of the synchronization process.

It should also be noted that the synchronization circuit is able to work independently, for example so as to be installed next to the readers of the same casino table but can also be integrated or attached to the central unit of the casino. management of readers.

Advantageously, the interface circuit comprises demultiplexing means between the data transmission lines from the readers.

Optionally, the interface circuit advantageously comprises means for delivering to the readers synchronized clock signals from the time base of said processing unit of the synchronization circuit.

The invention also relates to a non-contact token electronic chip reader adapted for implementing the method according to the invention in association with a synchronization circuit defined above, the reader comprising signal switching means. clock to switch from an internal time base to the time base of said processing unit.

The invention also relates to a non-contact token electronic chip reader adapted for implementing the method according to the invention in association with a synchronization circuit defined above, the reader having hardware and software means allowing him to within a plurality of readers to carry out the execution of the synchronization process, the coordinated management of the read and / or write cycles Tx / Rx, in particular in its variant to cut control and / or restore the current of antenna and / or in its variant with implementation of the accelerated collision management process.

The invention also relates to a system for reading and / or writing radio frequency contactless smart chips to be used with implementation of the method according to the invention in all its variants, having a plurality of readers defined above connected to a synchronization circuit defined above and managed by a central microprocessor control unit.

The invention also relates to a system for reading and / or writing radiofrequency non-contact chip chips for use with implementation of the method according to the invention in all its variants, comprising a plurality of clock-matched readers defined above and synchronized by the time base of a synchronization circuit defined above.

• la figure 1 représente une vue schématique d'un mode de réalisation d'un système de lecture et/ou écriture radiofréquence sans contact de jetons à puce électronique selon l'invention destiné à être utilisé avec mise en oeuvre du procédé selon l'invention ;
• la figure 2 représente un organigramme général des opérations effectuées par le circuit de synchronisation dans le cadre de la mise en oeuvre du procédé selon l'invention (dans sa variante avec prédétermination du nombre de lecteurs de la pluralité à synchroniser dans le prochain cycle de synchronisation CS);
• la figure 3 représente un organigramme d'opérations effectuées par un lecteur lors de l'exécution d'un cycle de synchronisation CS dans le cadre de la mise en oeuvre du procédé selon l'invention, notamment le protocole de transfert des durées TxL vers le circuit de synchronisation;
• la figure 4 représente un organigramme partiel d'opérations effectuées par le circuit de synchronisation lors de l'exécution du cycle de synchronisation CS présenté figure 3, notamment protocole de collection des nombres TxL par le circuit de synchronisation; et
• la figure 5 représente le schéma d'un circuit de commutation d'horloge pour lecteur permettant de passer du mode 'lecteur indépendant' au mode 'lecteur synchronisé'.

Other characteristics and advantages of the present invention will become apparent on reading the following description presented solely by way of nonlimiting example with reference to the accompanying drawings in which:

• the figure 1 represents a schematic view of an embodiment of a non-contact electronic chip token reading and / or writing system according to the invention intended to be used with implementation of the method according to the invention;
• the figure 2 represents a general flowchart of the operations performed by the synchronization circuit in the context of the implementation of the method according to the invention (in its variant with predetermination of the number of readers of the plurality to be synchronized in the next CS synchronization cycle);
• the figure 3 represents a flowchart of operations performed by a reader during the execution of a CS synchronization cycle as part of the implementation of the method according to the invention, in particular the protocol for transferring TxL times to the synchronization circuit ;
• the figure 4 represents a partial flowchart of operations performed by the synchronization circuit during the execution of the synchronization cycle CS presented figure 3 , in particular protocol for collecting TxL numbers by the synchronization circuit; and
• the figure 5 is a diagram of a reader clock switching circuit for switching from 'independent reader' mode to 'synchronized reader' mode.

The embodiment of the non-contact chip electronic reading and / or write system 10 according to the invention intended to be used with implementation of the method according to the invention illustrated schematically in FIG. figure 3 comprises, by way of example having no limiting character, a plurality 12 of three readers L1, L2 and L3 respectively referenced 12a, 12b, 12c. Each reader comprises at least one antenna, respectively 13a, 13b 13c, associated with the plate 14 a same game table or cash table to define corresponding read / write zones in which are arranged game chips 15a, 15b and 15c to electronic chip (plates or disks), either unitarily flat (chips 15b) or stacked (tokens 15a and 15c), the batteries can reach the number of 20 or more chips.

Still as a non-limiting example, the three readers 12a, 12b and 12c are of the VEGAS read-write device type (VEGRED2 version) produced by Gaming Partners International SAS. Each gaming chip includes an electronic chip 16 radio frequency transponder without contact, in this case a transponder Hitag Vegas produced by Philips Semiconductors.

The three readers 12a, 12b and 12c are connected by RS232 serial interfaces 17a, 17b and 17c to a same host computer OH 18 defining a central control unit of the readers transmitting commands to the readers and using the data provided by them. It should be noted that, according to a variant not shown and without departing from the scope of the invention, each reader can have its own central control unit (computer OH); for example, we can have a synchronization card, three readers and three independent computers. Each reader 12a, 12b or 12c comprises in particular a microprocessor reader μP (not shown) and a digital signal processor DSP (not shown), used in particular for the processing including the "anti-collision" algorithm. In general terms, the three readers 12a, 12b and 12c are loaded with the same software and configured identically so that the operating characteristics of the three readers 12a, 12b and 12c are identical (to the specific identity of each reader near).

Thus the TX transmission of a command to the chips by a reader (12a, 12b or 12c) is performed by strong modulation of the current of the antenna associated with the reader, detected by the chips 16 placed in the field thereof . Similarly, the reception Rx by the reader of the response of the chips as a result of a command is performed by the detection by the reader of the low modulation of the voltage on the antenna.

The energy required for the operation of the chip 16 is provided by the magnetic field of the antenna of the corresponding reader. The reader (12a, 12b or 12c) sends commands to the chips by modulating the amplitude of the oscillations of the magnetic field. The chips respond by modulating an internal resistance, the magnetic coupling ensuring the transmission of this modulation to the reader.

Still as a non-limiting example, the following states are distinguished in the operation of the chip 16 Hitag type.
Off. The chip is outside the field of the antenna.
Ready. The chip has just been placed in the field of the antenna. In this state it accepts only the SetCC command, after which it sends the serial number (SNR) to the reader and goes to the Initial state .
Initial. In this state the chip accepts the following commands.
SetCC - same effect as in Ready state .
ReadID - the reader sends N bits to the chips (1 ≤ N ≤ 31). Chips in which the first N bits of the SNR coincide with the N bits received respond by sending the other 32-N bits of the SNR; the other chips go to the Ready state .
Select - the drive sends 32 bits to the chips. The chip whose SNR coincides with the received bits responds by sending the data from its configuration page into memory and switches to the selected state; the other chips go to the Ready state .
SELECT. In this state, the chip accepts the read and write commands of the data as well as the Halt command, after which it switches to the Silent state .
Quiet. In this state the chip does not respond to any other command, thus allowing the reader to communicate with other chips. The only way to leave this state is to return to the Off state .

As a result of the SetCC and ReadID commands, it can happen that several chips send their responses at the same time. The responses of the chips are synchronized, in particular by the clock of the reader when it works in 'independent reader'mode; they contain 32 bits for SetCC and 32-N bits for ReadID . If the answers differ on certain bit positions, we say that we have collisions on the corresponding positions. The reader detects and processes these by the anti-collision algorithm.

In order to get the chips 16 out of the Silent state , the reader has the command HFReset momentary stopping of the current of the antenna. It also has the SetPowerDown command that turns off the antenna during periods of inactivity.

The three readers 12a, 12b and 12c are also connected to a synchronization circuit CSL 20 made by an electronic card comprising at least the following three main components: a microprocessor processing unit 22 model AT89C55WD of the company ATMEL, a circuit of Xilinx CPLD XC9572 interface model 24 and a MAX202 type 26 interface from the company Maxim.

The microprocessor 22 executes the synchronization protocol of the invention. It also communicates, through the serial interface 26, to a computer attached to the CSL circuit (in this case advantageously but not mandatory the computer 18) with which one can perform tests to check if all the components of the system (CSL, readers 12a, 12b and 12c and interconnect cables 17a, 17b and 17c) function properly. Note, however, that the presence of a computer for the CSL circuit 20 is not required during normal operation of the system 10 according to the invention.

• Il assure l'interface entre le microprocesseur 22 et les trois lecteurs 12a, 12b et 12c; en particulier, il agit comme démultiplexeur entre le microprocesseur 22 et les lignes DATA.
• Il distribue aux lecteurs un signal à 4 MHz obtenu en divisant la fréquence de 20 MHz de la base de temps du microprocesseur 22. Ce signal est utilisé par les lecteurs 12a, 12b et 12c afin de générer les ondes porteuses synchronisées à 125 KHz.
• Il assure l'initialisation du microprocesseur 22 lors de la mise sous tension et la réinitialisation de celui-ci en cas de blocage du programme. Pour cela, on a réalisé dans le circuit le circuit d'interface un sous-circuit (non représenté) de type « Watchdog » (circuit de surveillance) à une entrée pilotée par le microprocesseur 22 et une sortie qui pilote le signal RESET de ce dernier. Si le microprocesseur 22 ne pilote pas l'entrée du sous-circuit pendant un certain laps de temps, le sous-circuit pilote le signal RESET. Cette solution a été préférée à la place de l'utilisation du circuit « Watchdog » intégré dans le microprocesseur ou d'une capacité associée à la ligne RESET, car les deux dernières variantes ne peuvent pas assurer un démarrage correct du microprocesseur lors de la mise sous tension. En effet, il se peut que la mise sous tension d'un lecteur 12a, 12b et 12c précède celle du circuit 24 et que, par hasard, quelques lignes logiques reliant ce lecteur au circuit 24 se trouvent au niveau haut (normalement, le lecteur les remet au niveau bas lors de sa mise sous tension). Dans ces conditions, il est possible que la tension présente sur ces lignes engendre un démarrage partiel du microprocesseur 22, suffisant pour décharger une capacité liée à sa ligne RESET mais insuffisant pour assurer l'activation correcte de tout le processeur, en particulier de son circuit « WatchDog ». Ainsi, le microprocesseur 22 ne démarrerait pas lors de sa propre mise sous tension retardée par rapport au lecteur. Au contraire, le sous-circuit 24 commencera alors sa fonction et ne tardera de piloter le signal RESET du microprocesseur 22.

The interface circuit 24 performs the following functions:

• It provides the interface between the microprocessor 22 and the three readers 12a, 12b and 12c; in particular, it acts as a demultiplexer between the microprocessor 22 and the DATA lines.
• It distributes to readers a 4 MHz signal obtained by dividing the 20 MHz frequency of the microprocessor 22 time base. This signal is used by the readers 12a, 12b and 12c to generate the carrier waves synchronized at 125 KHz.
• It ensures the initialization of the microprocessor 22 during power up and reset of it in case of blocking the program. For this purpose, the interface circuit has formed a sub-circuit (not shown) of the "Watchdog" type (monitoring circuit) to an input controlled by the microprocessor 22 and an output which drives the RESET signal of this type. latest. If the microprocessor 22 does not drive the input of the subcircuit for a certain period of time, the subcircuit drives the signal RESET. This solution has been preferred over the use of the "watchdog" circuit integrated in the microprocessor or a capacity associated with the RESET line, since the last two variants can not ensure a correct start of the microprocessor when setting under pressure. Indeed, it is possible that the powering up of a reader 12a, 12b and 12c precedes that of the circuit 24 and that, by chance, some logical lines connecting this reader to the circuit 24 are at the high level (normally the reader lowers them when power is turned on). Under these conditions, it is possible that the voltage present on these lines generates a partial start of the microprocessor 22, sufficient to discharge a capacity related to its line RESET but insufficient to ensure the correct activation of the entire processor, particularly its circuit "WatchDog". Thus, the microprocessor 22 would not start during its own delayed power-up relative to the reader. On the other hand, the sub-circuit 24 will then begin its function and will soon be piloting the RESET signal of the microprocessor 22.

To enable the readers 12a, 12b and 12c to receive the 4 MHz signal supplied by the circuit 24, it is important to associate each reader with a clock switching circuit, for example the switching circuit 28 illustrated in FIG. figure 5 (after possibly turning off the internal clock divider circuit of the reader associated with the microprocessor of the latter). The circuit 28 is based on the Philips Semiconductors integrated circuit 74HC390 and operates the reader in 'synchronized reader' or 'independent reader' modes.

In the 'independent reader' mode, the dividing counters are placed in series by 5 (terminals CKB / QC) and by 2 (terminals CKA / QA) of the integrated circuit 30, thus obtaining division by 10 of the 20 MHz signal supplied by the internal processor of the reader (line 32), which gives the signal at 2 MHz (line 34) necessary for the reader to generate the carrier wave and other signals required by the transmission Tx and Rx reception. To do this, the single jumper 36 and the jumper 38a are closed, the jumper 38b being open.

In the 'synchronized reader' mode (present case of the readers 12a, 12b and 12c), the divider by 5 is quiescent while the 4 MHz signal supplied by the circuit 24 (line 33) has passed through the divider by 2 (CKA / QA); the 2 MHz signal necessary for the reader is thus obtained on line 34, the passage through the divider (CKA / QA) also intended to ensure clear transitions of the signal, eliminating the possible disturbances introduced by the transmission cable. . To do this, the single jumper 36 and the jumper 38a are open, the jumper 38b being closed.

The signals at 2 MHz are thus synchronized for all the readers 12a, 12b and 12c because they come from a common time base, that of the microprocessor of the circuit processing unit 22 of the synchronization circuit 20.

The coordinated management process according to the invention of the plurality of three readers 12a, 12b and 12c is implemented as follows.

The activity of each reader 12a, 12b or 12c takes place in response to the commands received from the central management unit 18 (hereinafter also called computer OH). Following such a command, the reader takes actions including zero, one or more Tx / Rx cycles.

For all intents and purposes it will be recalled that the Tx / Rx cycle itself of the readers comprises two steps: the transmission (Tx) of a command from the reader to the chips followed by the reception (Rx) of the response of the chips by the reader. In the particular case, but not limited to, readers 12a, 12b or 12c the answer Rx chips is automatic and follows almost immediately the end of the transmission Tx of the player concerned.

In the case of a synchronized reader, a Tx / Rx cycle is preceded by an additional synchronization process which in particular precedes and coordinates the transmission Tx of the command with respect to the Tx commands of the other readers. This process is intended to ensure that no Tx interval of a player is superimposed on any Rx interval of another player and hence that the strong modulation of Tx does not disturb the weak modulation of Rx. In other words, the synchronization process has the function of grouping the transmission operations Tx in a first time interval and of grouping the reception operations Rx in a second time interval, without overlapping between the two time slots. According to a preferred mode of implementation of the coordinated management method according to the invention, the process synchronizes the readers 12a, 12b and 12c in such a way that all the Tx transmissions of the active readers finish at the same time allowing the Rx receptions to start in same time. The process is implemented by executing a CS synchronization cycle presented below.

First, each reader 12a, 12b or 12c, made active by a command of the computer OH 18, calculates the duration TxL of the corresponding transmission Tx, as a 16-bit integer expressing the duration of the command in multiples of the period (8 microseconds) of the carrier wave of 125 KHz. This duration is then communicated by the interface circuit 24 to the CSL synchronization circuit 20, after which the reader awaits the START signal. Only after receiving this START signal from the CSL circuit 20, the reader executes the Tx / Rx cycle, that is, the Tx transmission operations of the control to the chip 16 and the chip Rx receiver. .

• 8 lignes DATA (DONNÉES) direction lecteur-circuit CSL ;
• une ligne BUSY (OCCUPÉ) direction lecteur-circuit CSL :
• une ligne REQUEST (REQUÊTE)direction lecteur-circuit CSL ;
• une ligne START (DÉPART) direction circuit CSL-lecteur.

Si l'octet supérieur de la durée TxL est nul, le transfert de TxL vers le circuit CSL 20 se fait en une seule étape, en utilisant les 8 lignes DATA pour le transfert de l'octet inférieur. Si l'octet supérieur n'est pas nul, le transfert se fait en trois étapes. On transfère d'abord un octet égal à zéro ; cette valeur n'étant pas une valeur valable pour une durée TxL, elle signale au circuit CSL 20 qu'un transfert en deux étapes va suivre, à savoir l'octet supérieur puis l'octet inférieur de la durée TxL.In order to be able to communicate the numbers TxL to the circuit CSL 20, each of the three readers 12a, 12b and 12c is connected to the interface circuit 24 by means of the following logical lines (see figure 1 ):

• 8 lines DATA (DATA) direction reader-circuit CSL;
• a BUSY line (BUSY) direction player-circuit CSL:
• a line REQUEST (direction) drive-circuit direction CSL;
• a line START (START) direction CSL-reader circuit.

If the upper byte of the duration TxL is zero, the transfer of TxL to the CSL circuit 20 is done in one step, using the 8 lines DATA for the transfer of the lower byte. If the upper byte is not zero, the transfer is done in three steps. First, a byte equal to zero is transferred; this value not being a value valid for a duration TxL, it signals to the circuit CSL 20 that a transfer in two steps will follow, namely the upper byte then the lower byte of the duration TxL.

• BUSY = 0, REQUEST = 0 - le lecteur ne participe pas au cycle de synchronisation CS courant (lecteur non actif) ;
• BUSY = 1, REQUEST = 1 - le lecteur vient de transférer l'octet inférieur de TxL ou un octet nul ;
• BUSY = 1, REQUEST = 0 - le lecteur vient de transférer l'octet supérieur de TxL,
• BUSY = 0, REQUEST = 1 - le lecteur attend le signal START.

The values assigned by the relevant reader 12a, 12b or 12c to the BUSY and REQUEST lines (see figure 1 ) have the following meanings:

• BUSY = 0, REQUEST = 0 - the reader does not participate in the current CS synchronization cycle (drive not active);
• BUSY = 1, REQUEST = 1 - the reader has just transferred the lower byte of TxL or a null byte;
• BUSY = 1, REQUEST = 0 - the reader has just transferred the upper byte of TxL,
• BUSY = 0, REQUEST = 1 - the reader is waiting for the START signal.

From the point of view of the CSL timing circuit 20, a CS timing cycle begins when a '1' is detected on at least one of the REQUEST lines. The cycle comprises two major steps: i) the collection of TxL numbers, extending from the beginning of the CS cycle (see figure 4 , step 400) until the detection of '0' on all BUSY lines (see figure, step 404, ii) the distribution of the START signals as a function of the numbers TxL. After these two major steps, the CSL circuit 20 returns to the idle state until the beginning of a new cycle.

In the figures 3 and 4 , the symbol <- (little arrow to the left) is used to indicate either the transfer of the values of variables or constants located on the right of the sign on the logical lines on the left, or the memorization of the values of the logical lines on the right in the variables on the left. The symbol [T] will mean that the expectation of achieving a certain logical condition does not extend to infinity, but until the expiry of a time counter, reset to zero in the first verification of the condition in question; this is to avoid blocking the system in an infinite loop in case of faulty operation in one of its components or connection cables.

The operation of the software program attached to the synchronization circuit CSL 20 and to the readers 12a, 12b and 12c integrates the infinite loop presented in FIG. Figure 2 . The TxL number transfer protocol to the CSL circuit 20 used by the reader is presented in Figure 3 while the TxL number collection protocol used by the CSL circuit 20 is presented in Figure 4 .

Regarding the infinite loop of the figure 2 once the CSL circuit 20 is energized, this circuit CSL first performs the collection of the TxL numbers of each of the plurality of readers 12 to keep only the active readers for which the number TxL is greater than zero (step 201 ). Depending on the number Nx of drives at TxL> 0, the CSL circuit 20 will synchronize the three readers (step 202), two readers (step 203) or a single reader (step 204).

The software program of the synchronization circuit CSL 20 has three logical 8-bit DATA ports (1 - 3) by means of which the circuit CSL reads the values deposited on the lines DATA by the three readers 12a, 12b and 12c. The CSL circuit also has the BUSY_REQUEST logical port with which it can simultaneously read the values of the BUSY and REQUEST lines connected to the three readers.

• le tableau à trois entrées TxL(1 - 3), où l'on mémorise les nombres TxL provenant des trois lecteurs ;
• le tableau à trois entrées TxLSET(1 - 3) ;
• la variable auxiliaire D.

The software program of the CSL synchronization circuit 20 further uses the following variables in the TxL collection protocol illustrated. figure 4 :

• the three-input table TxL (1 - 3), where the TxL numbers from the three readers are stored;
• the three input TxLSET array (1 - 3);
• the auxiliary variable D.

The TxL and TxLSET arrays are reset at the end of each CS synchronization cycle. A '1' in the i-th input of TxLSET means that the transfer of the TxL number for the i-th reader is complete.

The synchronization process illustrated in figure 3 (reader side 12a 12b or 12c, hereinafter the i-th reader) and at the figure 4 (circuit side CSL 20, according to an iterative process i ranging from 1 to NL = 3 in the present case) is now presented:

After receiving a command from the computer OH 18, the i-th reader places a '1' on the BUSY line (step 301), thereby signaling the CSL synchronization circuit 20 its intention to participate in the CS synchronization cycle. If the top byte of his number TxL is zero (condition 301 '), the ith reader transfers the lower byte of its TxL by depositing this byte on the DATA lines (step 302), then placing a' 1 'on the REQUEST line (step 303) ). Following the '1' detected on the REQUEST line of the i-th reader (step 401), the CSL circuit 20 reads the value of the DATA port (i) (step 402); this being non-zero, the CSL circuit deposits it in the lower byte of TxL (i) and writes a '1' in TxLSET (i) (step 403), the transfer of TxL being thus completed for the i-th reader.

If the upper byte of its TxL is non-zero (condition 301 '), the ith reader deposits a zero on the DATA lines (step 304), then places a' 1 'on the REQUEST line (step 305). Following the '1' detected on the REQUEST line of the i-th reader (step 401), the CSL circuit 20 reads the value of the DATA port (i) (step 402); the latter being zero and the two conditions TxL (i) = 0 and TxLSET (i) = 0 being satisfied, the CSL circuit knows that a transfer of a 16-bit TxL number must follow. For this purpose, the circuit CS places a '1' on the START line of the i-th reader (step 405); in response (condition 305 '), the i-th reader transfers the upper byte of its TxL by depositing this byte on the DATA lines (step 306), then placing a' 0 'on the REQUEST line (step 307). Following the '0' on the REQUEST line (condition 405 '), the CSL circuit 20 deposits the value of DATA (i) into the upper byte of TxL (i) (step 406), and then resets the START line of i-th reader at '0' (step 407). In response to '0' on the START line (condition 307 '); the i-th reader transfers the lower byte of its TxL by depositing this byte on the DATA lines (step 302), then placing a '1' on the REQUEST line (step 303). Following the detection on the REQUEST line of the i-th reader, CS reads the value of the DATA port (i) (step 402); even if this one is null (it is possible that the lower byte of TxL is null if the upper byte is not it), the conditions TxL (i)> 0 and TxLSET (i) = 0 (condition 402 ') signal to the CSL that it is now the transfer of the lower byte of TxL; therefore, the CSL circuit 20 deposits the value of DATA (i) in the lower byte of TxL (i) and writes a '1' in TxLSET (i) (step 403), thus the TxL transfer is completed for the i-th reader.

The i-th reader now starts waiting for permission to send the command to the chips (execution of the Tx transmission). For this purpose, it resets the BUSY line while keeping the '1' on the REQUEST line (step 308). The permission is granted by the CSL circuit by placing a '1' on the START line of the i-th reader (condition 308 '); at this time, the i-th reader resets its REQUEST line (step 309), then places a '1' on its BUSY line (step 310). Then the reader runs its Tx / Rx cycle and sends its command to the chips and receives the response. The current Tx / Rx cycle is thus completed.

However, the transmission of the START signal for the i-th will take place only during the actual synchronization (with the distribution of the signals START as a function of the numbers TxL) after the end of the iteration process described in FIG. figure 4 (the collection of TxL numbers), or after interrogation of all the other readers of the plurality of readers (condition 407 '). If one of the readers is inactive, either with the signals REQUEST = 0 and BUSY = 0 (conditions 401 'and 401 "), this reader will be discarded from the actual synchronization process executed later and the values TxI (i) and TxISET (i ) Finally, the actual synchronization process will begin after step 404 of ending the collection of TxL numbers, once fulfilled the dual condition of at least one signal REQUEST = 1 and the three signals BUSY to zero (condition 407 ").

If the command of the computer OH 18 requires another Tx / Rx cycle, the fact that we kept the '1' on the BUSY line guarantees the participation of the i-th reader in the CS synchronization cycle which will follow the CS cycle current.

After having completed all the Tx / Rx cycles requested by the execution of the command of the computer OH 18, the i-th reader will normally reset its BUSY line, thus signaling to the circuit CSL 20 that it has become inactive . Another CS synchronization cycle can begin without the participation of the i-th reader. If the latter receives a command from the computer OH 18 during the course of a CS synchronization cycle in which it does not participate, it will have to wait until the next CS cycle. If this is undesirable in some situations, the delayed reset mode of the BUSY line is alternatively provided (not shown). In this mode, the reader does not reset the BUSY line immediately after completion of the command of the OH computer 18, but with a delay of approximately 80 milliseconds. This delay allows the computer OH 18 to immediately send a new command to the reader that will not miss the next CS synchronization cycle. If the computer OH 18 does not wish to send a new command, it can ask the reader to reset the BUSY line.

In addition, the commands of the computer OH 18 for the purpose of establishing and cutting the current of the antennas 13a, 13b and 13c do not contain any real Tx / Rx cycle. However, these orders are preferentially also synchronized. For this purpose, the reader indicates to the circuit CSL a value of TxL assimilated of sufficient duration so that the current of the antenna is stabilized, then executes the command concerning the current (command CA assimilated to a transmission Tx) after the reception of the signal START .

The CSL synchronization circuit 20 also starts the synchronization of the current CS cycle when all the BUSY lines from the three readers 12a, 12b and 12c are set to zero. This condition is distinguished from the situation where all readers are idle by the fact that there is at least one REQUEST line set to '1'. The synchronization method depends on the number of readers participating in the current CS synchronization cycle, equal to the number Nx of the non-zero TxL values that have just been transferred.

• Ordonner les valeurs des nombres TxL. On utilise à cet effet un tableau à trois entrées READERS(1 - 3), en écrivant dans ces entrées les numéros des trois lecteurs (12a, 12b ou 12c) de façon que l'on ait TxL(READERS(1)) >= TxL(READERS(2)) >= TxL(READERS(3)).
• Placer un '1' sur la ligne START du lecteur dont le numéro est écrit dans READERS(1), correspondant à l'émission de l'ordre d'exécution du cycle Tx/Rx du lecteur pour lequel la transmission Tx de l'instruction de commande est la plus longue (premier lecteur lancé).
• Attendre un laps de temps égal à (TxL(READERS(1)) -TxL(READERS(2))) fois la période de l'onde porteuse, correspondant au délai d'émission d'ordre d'exécution du cycle Tx/Rx du second lecteur par rapport au premier lecteur lancé.
• Placer un '1' sur la ligne START du lecteur dont le numéro est écrit dans READERS(2) (lancement du second lecteur).
• Attendre un laps de temps égal à (TxL(READERS(2)) -TxL(READERS(3))) fois la période de l'onde porteuse, correspondant au délai d'émission d'ordre d'exécution du cycle Tx/Rx du troisième lecteur par rapport au second lecteur lancé.
• Placer un '1' sur la ligne START du lecteur dont le numéro est écrit dans READERS(3) (lancement du troisième lecteur).
• Attendre [T] que les lignes BUSY de tous les trois lecteurs soient mises à 1'.
• Remettre à zéro les lignes START des trois lecteurs.
• Remettre à zéro les tableaux TxL(1 - 3) et TxLSET(1 - 3).

The synchronization process as performed for three participating readers (Nx = NL = 3) is presented below (see figure 2 ):

• Order the values of TxL numbers. For this purpose, use a table with three READERS entries (1 - 3), writing in these entries the numbers of the three readers (12a, 12b or 12c) so that we have TxL (READERS (1))> = TxL (READERS (2))> = TxL (READERS (3)).
• Place a '1' on the START line of the reader whose number is written in READERS (1), corresponding to the transmission of the order of execution of the Tx / Rx cycle of the reader for which the transmission Tx of the instruction command is the longest (first drive launched).
• Wait for a time equal to (TxL (READERS (1)) -TxL (READERS (2))) times the period of the carrier wave, corresponding to the Tx / Rx cycle execution order transmission delay the second drive relative to the first drive launched.
• Place a '1' on the START line of the player whose number is written in READERS (2).
• Wait for a time equal to (TxL (READERS (2)) -TxL (READERS (3))) times the period of the carrier wave, corresponding to the Tx / Rx cycle execution order transmission delay of the third drive compared to the second drive launched.
• Place a '1' on the START line of the player whose number is written in READERS (3).
• Wait [T] until the BUSY lines of all three readers are set to 1 '.
• Reset the START lines of the three readers.
• Reset the tables TxL (1 - 3) and TxLSET (1 - 3).

The process in the case of two participating readers is similar, with the only difference that it is for two readers instead of three.

The process in the case of a single participating reader is to immediately give the START signal, wait [T] for the BUSY line of the reader to be set to 1, reset the START line of the reader and reset. Tables TxL (1 - 3) and TxLSET (1 - 3).

It should be noted that the invention is not limited to a plurality NL of 3 readers and can be implemented with a larger number of readers subject to modify the circuits and software accordingly based on the information data above and to the extent that commands sent by separate readers do not significantly disturb each other.

It should also be noted that the invention is not limited to reading and / or writing contactless radio frequency electronic chip chips for casino and gaming rooms but applies to all applications of reading / contactless RFID entries of tokens, plates or electronic smart card (for example non-limiting, tokens or access card, countermarks or electronic tags, etc.).

The invention is also not limited to the readers and / or the reader / chip and chip / reader communication protocol by Tx / Rx cycles described above. The coordinated management method of a plurality of readers and the synchronization process according to the invention are applicable i) to all readers using a command type communications protocol sent by the reader followed by the responses sent by the chips, the responses can be automatic and immediate (as in the Tx / Rx cycle described above) or automatic and not immediate or emissions controlled over time; and ii) optionally to all readers having antenna current stop commands, the electronic chips being adapted, in each of the above-mentioned cases, to the readers both from the hardware and software point of view.

Claims (18)

1. Method for coordinated management of a plurality (12) of contactless radio-frequency readers (12a, 12b, 12c) of chips (15a, 15b, 15c) incorporating an electronic microcircuit (16), in which a current transmit/receive cycle Tx/Rx between a reader (12a, 12b, 12c) and the microcircuits (16) accessible by the reader includes a transmit operation Tx of transmitting a command instruction from the reader to the microcircuits followed by a receive operation Rx of the reader (12a, 12b, 12c) receiving the response from the microcircuits (16), the transmit/receive cycles Tx/Rx of the active readers being subject to a synchronization process to group the transmit operations Tx in a first time interval and to group the receive operations Rx in a second time interval with no overlap between the two time intervals, wherein the transmit operations have different durations and the grouping of the transmit operations Tx are carried out by the synchronization process such that the transmit operations Tx finish at substantially the same time, to be used with readers having the function of detecting and managing collisions at the level of simultaneous responses of a plurality of microcircuits to the same command instruction of a Tx/Rx, characterized in that it is associated with means adapted to implement the following accelerated collision management process:

   - on detection of a collision by virtue of a mismatch between the value '0' or '1' of a bit of the response and the expected value for that bit, determining the "strong" or "weak" nature of the collision as a function of the level of uncertainty as to the detected value of the response bit concerned;

   - iteratively processing collisions, only "strong" collisions being processed on the first iteration.
2. Method according to claim 1, characterized in that the synchronization process includes:

   - a step of collecting the TxL durations of the transmit operations Tx for sending command instructions of the first awaiting Tx/Rx cycles of the active readers (12a, 12b, 12c), and

   - a step of sending the active readers instructions to execute the transmit operations Tx for sending the command instructions of the Tx/Rx cycles spread over time and in order of decreasing TxL duration, beginning with the reader assigned the command instruction of the Tx/Rx cycle having the greatest TxL duration, the delay between one execution instruction and the next being equal to the difference between the TxL durations of the Tx/Rx cycle command instructions to be transmitted by the corresponding two readers, up to the execution instruction associated with the shortest TxL duration.
3. Method according to claim 2, characterized in that the synchronization process includes synchronization of the CA instructions for connecting and/or disconnecting power from the antenna (13a, 13b, 13c) of one or more readers of said plurality of readers, by assimilating:

   - these CA instructions as command instructions of a Tx/Rx cycle to an active reader,

   - the time for the antenna current to stabilize after the execution of a CA instruction as the TxL time of the transmit operation Tx sending the Tx/Rx cycle command instruction to the active reader, said stabilization time being referred to hereinafter as the assimilated TxL duration, and the CA instruction being referred to hereinafter as the assimilated Tx transmit operation, and

   - an instruction to execute a CA instruction as an instruction to execute a transmit operation Tx of a Tx/Rx cycle in which the Rx receive operation has a null duration, hereinafter referred to as an assimilated Tx/Rx cycle.
4. Method according to either claim 2 or claim 3, characterized in that the real and/or assimilated TxL durations take the form of multiples of the period of the carrier used by the readers (12a, 12b, 12c).
5. Method according to anyone of claims 2 to 4, characterized in that the synchronization process is effected by a synchronization circuit (20) in accordance with a CS synchronization cycle initiated either by the first request for authorization to execute a real or assimilated Tx/Rx cycle submitted by a reader following a request from a central control unit (18) of the reader, or automatically at the end of the last Rx receive operation of real Tx/Rx cycles corresponding to the preceding CS synchronization cycle or, if there is no real Tx/Rx cycle, at the end of the assimilated Tx transmit operations.
6. Method according to claim 5, characterized in that all the readers (12a, 12b, 12c) that have transmitted requests for authorization to execute a real or assimilated Tx/Rx cycle since the start of execution of the preceding CS synchronization cycle participate in a new CS synchronization cycle.
7. Method according to claim 6, characterized in that all active readers that have participated in the preceding synchronization cycle also participate in the new CS synchronization cycle.
8. Method according to anyone of claims 5 to 7, characterized in that, for each CS synchronization cycle, the step of collecting real and/or assimilated TxL durations is effected for all the NL readers of the plurality (12) of readers, with determination of the number Nx of readers for which an instruction to execute the real or assimilated Tx transmit operation must be sent, and the step of sending instructions to execute the Tx transmit operation is adapted as a function of Nx.
9. Method according to anyone of the preceding claims, characterized in that the clock signals of each reader of the plurality of readers (12a, 12b, 12c) are synchronized to the same timebase.
10. Method according to claim 1, characterized in that discrimination between "strong" and "weak" collisions is obtained by fixing for each reader (12a, 12b, 12c) a predetermined sharing threshold associated with the level of uncertainty as to the detected value of the response bit concerned.
11. Method according to claim 10, characterized in that the sharing threshold is selected to distinguish between real collisions, "strong" collisions resulting from simultaneous responses from a plurality of microcircuits (16) separate from false collisions, and "weak" collisions resulting in particular from electromagnetic interference external to the readers (12a, 12b, 12c) or interference between readers with antennas in close proximity during sending of the responses Rx.
12. Synchronization circuit (20) for a plurality (12) of contactless radiofrequency readers of chips (15a, 15b, 15c) incorporating an electronic microcircuit adapted to implement the method according to anyone of the preceding claims, characterized in that it includes a microprocessor-based processing unit (22) that is adapted to effect the synchronization process and is associated with an interface circuit (24) adapted to be readily connected to each of the readers (12a, 12b, 12c) of said plurality (12) of readers.
13. Synchronization circuit (20) according to claim 12, characterized in that the interface circuit (24) includes means for demultiplexing data transmission lines from the readers.
14. Synchronization circuit (20) according to either claim 12 or claim 13, characterized in that the interface circuit (24) includes means for delivering to the readers (12a, 12b, 12c) clock signals synchronized to the timebase of said processing unit (22).
15. Contactless radio-frequency reader (12a, 12b, 12c) of chips (15a, 15b, 15c) incorporating an electronic microcircuit (16) adapted to implement the method according to anyone of claims 1 to 11 in conjunction with a synchronization circuit (20) according to anyone of claims 12 to 14, characterized in that it has access to or includes hardware and software means enabling it to effect the synchronization process within a plurality (12) of readers, the coordinated management of read and/or write Tx/Rx cycles, in particular in the variant controlling connection of power to and/or disconnection of power from the antennas (13a, 13b, 13c) and/or in the variant employing the accelerated collision management process.
16. Contactless radio-frequency reader (12a, 12b, 12c) of chips (15a, 15b, 15c) incorporating an electronic microcircuit (16) adapted to implement the method according to anyone of claims 1 to 11 in conjunction with a synchronization circuit (20) according to any one of claims 12 to 14, characterized in that it includes clock signal switching means (28) for switching from an internal timebase to the timebase of said processing unit (22).
17. System of contactless radio-frequency read/write reader (10) of chips (15a, 15b, 15c) incorporating an electronic microcircuit (16) adapted to implement the method according to anyone of claims 1 to 11, characterized in that it includes a plurality (12) of readers according to anyone of claims 15 and 16 connected to a synchronization circuit (20) according to anyone of claims 12 to 14 and managed by a microprocessor-based central control unit (18).
18. System of contactless radio-frequency read/write reader (10) of chips (15a, 15b, 15c) incorporating an electronic microcircuits (16) adapted to implement the method according to anyone of claims I to 11, characterized in that it includes a plurality (12) of readers according to claim 15 using adaptation of the clock signal and synchronized by the timebase of a synchronization circuit (20) according to claim 14.

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