Abstract:
A memory card or chip card reader system in which the reader is connected to a microcomputer by a connection link enabling the connection, in a branch, of another computer peripheral such as a printer. This link enables the transmission, to the reader, of at least one operation signal. Such a system makes it possible to provide for a reader that has no microprocessor and therefore has no processing function. Furthermore, the microprocessor can possess only one connector common to the reader and printer. Applications to microcomputer links and card readers.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a memory card or chip card reader system and more particularly to a card reader that can be connected to a microcomputer. Such a reader can be applied to the reading of synchronous memory type cards, for example telephone cards, as well as to the reading of the bank card types known as chip cards. 
     2. Discussion of the Related Art 
     The many readers that are in existence have the common feature of operation achieved by a microprocessor of their own that manages the sampling of an input/output line of the card and the associated transmission protocol. Furthermore, the microprocessor of the reader also provides for the interfacing with the microcomputer. Each reader therefore has a microprocessor whose design is developed to a greater or lesser extent and has a considerable effect on the cost of the reader. 
     The cards accepted by each reader and the protocols of transmission to the microcomputer are fixed in the microprocessor of the reader. This microprocessor finds out whether it can process the card presented to it and, together with the microcomputer, decides on the transmission protocol. 
     The connection of a card reader to the microcomputer is done by means of a connector or port on the microcomputer that is reserved solely for the connection of the reader. This port may be designed for serial or parallel transmission. This therefore necessitates a specific port for the card reader on each microcomputer. This is a drawback because it is useful, for reasons of cost or flexibility of use, to reduce the number of ports in the microcomputer. 
     SUMMARY OF THE INVENTION 
     The invention relates to a memory card (or chip card) reader system comprising at least one microcomputer equipped with at least one input/output connector of the microcomputer as well as a card reader. This system comprises notably a connection link enabling the connection, in a branch, to the same input/output connector of the microcomputer, of the card reader as well as another peripheral device. This link enables the transmission, to the reader, of at least one signal to validate the operation of the reader, the reader having a circuit to identify this validation signal. 
     A design of a transmission architecture such as this has now become possible because of the development of microcomputers. The processing capacities are now sufficiently developed and, in particular, the processing speeds enable the microcomputer to take charge of the work done hitherto by the microprocessor of the reader. 
     For example, an 8086 type processor worked with 8 bits at a clock frequency of 4 to 5 MHz. The 286 type processor with the 16-bit registers works at a frequency of 16 MHz. At present, the 386 and 486 type processor work with 32-bit and 64-bit registers respectively and at speeds corresponding respectively to 33 MHz and 66 Mhz. Furthermore, certain new processors integrate architectural improvements such as ultra-fast memories known as cache memories that make it possible to reduce memory-call operations and increase the processing power of the processor. 
     Under these conditions, a microcomputer has become capable of taking charge of the work of managing the card reader. It will notably be capable of managing the transmission protocols to the reader. The result of this is that it will be easy to modify the protocols since it will be possible to modify them in the microcomputer. 
     According to an embodiment of the invention, the card reader does not have any microprocessor, the microcomputer being appropriately programmed to exchange information with the reader according to a protocol adapted to this reader. 
     According to this design, the microcomputer is fast enough to sample the input/output line of the card. The transmission speed is limited only by the speed of the microcomputer. 
     However, while the microcomputer can process an information element at each bit time without any difficulty, it is difficult for it to produce the necessary time base with sufficient precision. Consequently, for reception, the reader has the task of carrying out a high-precision sampling of the input/output line to keep the information available for the microcomputer software throughout the duration of a bit time. The transmission works according to a similar principle. The bits transmitted by the microcomputer software are resynchronized by the reader. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The different objects and features of the invention shall appear more clearly in the following description and in the appended figures, of which: 
     FIGS. 1a and 1b show simplified exemplary embodiments of the system of the invention; 
     FIG. 2 shows a simplified exemplary embodiment of the reader according to the invention; 
     FIG. 3 represent data signals and their transmitted sampling signals; 
     FIGS. 4a to 4b show a detailed exemplary embodiment of the reader according to the invention. 
    
    
     DETAILED DESCRIPTION 
     An object of the invention is to make a card reader that can be connected to a parallel port of the microcomputer, generally used for the printer. The printer then shares the same port as the card reader. This does not complicate the connection equipment of the microcomputer. The invention provides a simplified reader, related to this connection mode, that is capable of working in cooperation with the microcomputer. 
     However, such a design comes up against the question of the compatibility of the reader with the microcomputer to which it is connected, as well with the peripherals (such as printers) connected to the microcomputer. Furthermore, a reader such as this, connected to the same port as another peripheral, should not disturb the working of this other peripheral nor be disturbed by this other peripheral. 
     A valuable application of the reader of the invention lies in the use of memory cards or chip cards as a software protection key. Indeed, the great variety of memory cards and chip cards and their flexibility of use make them products that are particularly well suited to checking access to software. The following are some examples of services that can easily be provided with a memory card (or a chip card) used in a reader according to the invention: 
     the management of the closing date of validity for a hired or demonstration software program; 
     the prepayment of time units for the effective use of the software program; 
     the validation of functions according to user, namely permitting a user to use determined functions of a software program under operation in the microcomputer; 
     the replacement of several keys for software by a single card. 
     Another characteristic of the reader according to the invention lies in its architecture. Indeed, this reader requires no microprocessor. The software of the microcomputer (PC) directly guides the reader. Consequently, the products and protocols accepted depend solely on the software of the microcomputer. 
     This organization gives rise to another appreciable advantage that lies in the open-ended nature of the system and its flexibility of use and adaptation. For example, the updating of the software of the microcomputer is done by the loading of diskettes whereas, in known readers, a change in product or protocol dictates a change in the program memory of the microprocessor of the reader. Certain readers can be remote-loaded but are costly and hardly applicable for current applications. 
     Referring to FIGS. 1a and 1b, a description shall be given first of all of a general exemplary embodiment of the system according to the invention. 
     These figure show a microcomputer referenced PC (such as a personal computer), a card reader LC and another computer peripheral such as a printer IMP. 
     The card reader LC may be capable of reading cards CA of the memory card or chip card type. According to the invention, these cards may belong to a variety of models and brands. 
     In particular, according to the invention, the microcomputer PC has only one connector or port CO1 for both the connection with the card reader LC and connection with the printer IMP. 
     According to FIG. 1a, the card reader has a port CO2 for the connection of the reader to the port CO1 of the microcomputer by means of the cable CA1 and a port CO3 for the connection of the reader to the port CO4 of the printer by means of the cable CA2. The ports CO2 and CO3 are interconnected in the reader. 
     According to FIG. 1b, the port CO2 of the reader is connected to the port CO1 of the microcomputer but the cable CA2 is connected in a branch connection to the cable CA1 in such a way that the reader has only one port CO2 to which the port CO4 of the printer IMP can be connected. 
     FIG. 2 shows an exemplary simplified embodiment of the reader of the invention indicating the wires and signals needed for communications between the microcomputer and the card reader. FIGS. 4a and 4b show a detailed practical embodiment with, notably, the standardized meanings of the signals attached to a standardized parallel type connector. 
     The upper part of this FIG. 2 shows the ports CO2 and CO3 enabling the connection of the reader respectively to the microcomputer PC and to a peripheral such as the printer IMP. 
     Connection devices such as JC7 and JC9 enable the connection of a card to the reader. Should there be a card in the reader, a circuit PR detects the presence of this card and gives a presence signal on the wire CARD to the microcomputer PC. 
     The reader LC has a circuit STR enabling the identification of a signal received from the microcomputer and informing it that it will exchange information elements with the microcomputer. 
     The microcomputer provides a signal on a wire called ST READER. This signal is identified by the circuit STR. If necessary, the circuit STR verifies the absence of a signal on a wire called STROBE. Indeed, a signal STROBE enables the starting of a call from the microcomputer PC to the printer IMP. The reader LC is then activated in reception mode. 
     In the case of the transmission of information elements from the microcomputer PC to the reader LC, the microcomputer PC sends information elements on a wire called DATA OUT. 
     After the start of each information bit, a clock circuit H gives, on a wire called SYNCH BIT, a clock signal whose leading edge is located after the leading edge of the bit, for example in the middle of each bit. This signal SYNCH BIT is used by the microcomputer to sample or bring about the sampling of the bits received on the E/S or DATA OUT wires. 
     For each transmitted bit, the reader LC, by means of a recording circuit EN, samples the information bit DATA OUT with the validation signal CLK EN. This enables the reader to take the value of each bit (typically by storing it in a register) by getting rid of the effect of parasites and untimely modulations that may affect the start (leading edge) of each bit. The circuit EN then retransmits, as the case may be, the information elements on the connection JC7 to the card. The circuit EN has, for example, a monostable circuit that produces a calibrated delay. This monostable circuit preferably has a counter to count the delay period. The circuit EN and the circuit STR are preferably formed by means of a 74HC174 type circuit. 
     In the case of the transmission of information in the direction going from the reader l,C to the microcomputer PC, a circuit DIN that has received information elements from the card by the connection E/S connected to the terminal JC7 presents them on the wire DATA IN. The circuit PR, the circuit H and the circuit DIN are preferably set up by means of a 39V18 type integrated circuit. 
     FIG. 3 shows an example of transmitted bits DATA OUT. This figure shows, offset with respect to the leading edges of the bits, the validation signal CLK EN and the corresponding data element transmitted to the card by the connection E/S. 
     The card reader thus described may be implemented without any microprocessor, unlike existing card readers. The card reader therefore no longer requires any smart functions. The functions such as those of protocol conversion, for example the conversion of byte-oriented protocols into byte group oriented protocols may be done in the microcomputer PC. Similarly the adaptation to the type of card may be done in the microcomputer. 
     The card reader system is therefore simplified as regards the reader but gives flexibility of use by transferring the possibilities of the modification of the operation to the microcomputer. 
     Furthermore, the system of the invention provides for security of transmission even though the reader no longer has any operational autonomy. 
     FIGS. 4a and 4b show a detailed exemplary embodiment of a card reader. 
     FIGS. 4a and 4b are placed together in a state of graphic correspondence. 
     These figures again show the ports CO2 (to the microcomputer) and CO3 (to the printer). 
     At the bottom of these figures is the port CO5 for the connection of a card. The figure also shows certain wires described with reference to FIG. 2. 
     The different connection wires bear the names of the signals that they convey. The signals have the following functions: 
     STROBE=signal for the validation of data to the printer; 
     FEED=page feed signal to printer; 
     BAUD 0, 
     BAUD 1=signals for the printer or initialization of the reader; 
     ERROR=error signal for the printer; 
     END SHORT=the signal END indicates the end of a byte and the signal SHORT indicates an operation in synchronous mode or a printer data element; 
     ST READER=operation validation signal intended for the reader or a printer data element; 
     RST --  EN=signal to reinitialize or reset the card or a printer data element; 
     CLK --  EN=signal to validate the clock of the card or a printer data element; 
     DATA --  OUT=data signals sent out by the microcomputer to the reader; 
     VCC --  EN=signal to validate the electrical supply of the card or a printer data element; 
     CARD 
     (or ACK)=signal indicating the presence of a card in the card reader; or acknowledgment sent out by the printer; 
     SYNCH --  BIT=validation clock signal sent out by the reader to the microcomputer or indication that the printer is busy; 
     DATA IN=signal representing information elements sent by the reader to the microcomputer, or indications that the printer is connected. 
     With respect to the port CO5 for the connection of a card, the different connections, which are duplicated to meet different connection standards, have the following functions: 
     JC5/JC15=supply of a ground GND; 
     JC4/JC14=transmission of the control signal known as B for a memory card or chip card; 
     JC9/JC10=the presence of a card has the effect of prompting the opening of the contacts normally closed at rest and connecting the two connections JC9 and JC10. The opening of this contact indicates the presence of a card; 
     JC7/JC17=transmission of I/O information in both directions of transmission; 
     JC3/JC13=clock signal for the validation of transmitted data bits. 
     Since the microcomputer connector used is preferably of the parallel connector type, it will be noted that in the invention the useful data are exchanged according to a series protocol with the wires DATA OUT and DATA IN. 
     Having thus described at least one illustrative embodiment of the invention, various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description is by way of example only, and not intended to be limiting. The invention is limited only as defined in the following claims and the equivalents thereto.