EP0571848A1 - Local paging receiver - Google Patents

Abstract

This receiver, commonly called "pager", is intended to receive radio broadcast message signals, comprising call signalling information and the message information. It comprises a receiver (3) intended for receiving and demodulating the coded message signals, a memory (5) for holding the said message information, a decoder (4) of the coded message signals for selectively supplying the message information to the memory (5) and means of function control (8) capable of supplying control signals to the memory and of receiving therefrom the message information which is held there. The memory (5) comprises internal processing means for controlling the reception of the message information originating from the said decoder (4). Hence, selected message information supplied by the decoder (4) can be held in the memory without it being necessary to make use of the command from a microcomputer or from a microprocessor external to this memory, which thus becomes, to some extent, "intelligent". Application especially to pagers built into a wristwatch.

Description

The present invention relates to local call systems and, more particularly, to the storage and manipulation of message information received by a local call receiver. In the remainder of this description, the term "pager" will be used to designate such local pagers, since this term is now very widely accepted and used in French-speaking countries, both by specialists and by the general public who use it. is the user.

The present invention can be used in portable pagers capable of receiving message signals transmitted at high frequency, the invention being described below in relation to this example of application to which it is however not limited.

Telecommunication systems in general, and local calling systems in particular, using broadcast message signals are currently widely used to pager calls for the purpose of selectively sending information to them. from a central station. This information is transmitted by means of coding schemes and determined message formats, such as those known under the term POCSAG or GOLAY. As regards the POGSAG scheme, we can refer in particular to the recommendation of CCIR 584-1, Dubrovnik, 1986.

The predominant transmission coding schemes used for pager calling have evolved from simple systems based on sequential acoustic signals to formats based on code words composed of many bits, and the functions offered to the user have changed from concomitantly from a simple acoustic warning signal to a warning signal multifunctional complex involving reading on a display of digital or alphanumeric data.

To realize these multifunctional possibilities, current local call systems and pager receivers include microprocessors, or even microcomputers, allowing them to react to information containing a wide variety of coded broadcast message signals. To this end, the already known pagers are capable of receiving these signals, of demodulating them, of extracting therefrom the dedicated information of call signaling and the message information proper, of memorizing this information and finally of displaying certain selected elements of the message transmitted.

The prior art pagers also allow the user to have special functional possibilities such as the subsequent recall of messages already received and the display of the number of messages received or the current time.

The microcomputers used in known pagers are designed to control the operation of the receiver so that it can receive the broadcast message signals, and to perform the functions of decoding the coded message signals, of storing given message signals , for controlling the display and for manipulating the stored message signals, so that the various functional possibilities to be controlled can be implemented.

One of the important requirements imposed on a pager is that he must process the information received in real time, otherwise there is a risk of loss of information, for example due to the fact that the decoding speed is too high low compared to that at which the information is received. Consequently, the operations carried out by the microcomputer relating to the reception, decoding, storage and manipulation of the coded message information received must be fast enough for the results obtained to be useful for controlling the device without the risk of loss of information. It is therefore necessary to use particularly efficient microcomputers operating at high speed.

The clock frequency required to achieve high operating speeds in real time can be 500 kHz, for example. These high clock frequencies increase the supply voltage and the energy consumed by the pager, while making it more expensive. However, the battery required to power existing microcomputers largely determines the cost, dimensions and weight of the pagers.

In addition, such high clock frequencies and the signals they induce in pager circuits at harmonic frequencies of the clock frequency, seriously disturb the quality of processing that should be expected in a good pager. . Furthermore, the high energy consumption and the physical limits of these microcomputers also lead to a limitation of the functions that can be implemented and offered by existing pagers.

It is also common to repeat two or three times the broadcast of message signals to ensure that the pager for which these signals are intended receives them correctly. Known pagers thus include memory space whose dimensions must be compatible with a storage not only of the original message signals, but also of their repetitions. The additional memory capacity required by these repetitions further increases the energy consumption and the cost of known pagers.

The object of the invention is to provide a pager which attenuates or even eliminates the drawbacks of pagers of the prior art.

The invention therefore relates to a pager intended to receive broadcast message signals, comprising call signaling information and message information, said message information comprising one or more messages, said pager comprising a receiver intended to receive and to demodulate the coded message signals, a memory device, for memorizing said message information, a decoder intended to decode said coded message signals and for selectively providing said message information to said memory device, function control means capable of supplying control signals to said memory device and receiving message information stored therein , said pager being characterized in that said memory device comprises internal processing means for controlling the reception of the message information coming from said decoder.

Thus, selected message information supplied by the decoder can be memorized by the memory device without it being necessary to have the control of an external microcomputer or microprocessor in relation to this communication device. memory, the latter thus becoming, in a way, "intelligent".

As a result, the selected message information can be stored directly and in real time in the "intelligent" memory device which allows the microcomputer or the external microprocessor with respect to the storage means, to accomplish other pager functions, without clock frequencies or processing speed being as high as in known pagers.

According to another characteristic of the invention, the pager can also be adapted to handle the message information stored in the memory device, so that the deletion, copying and shifting of the information thus stored, can be performed inside the memory device, thereby removing the constraints imposed by these operations to the function control means, in other words to the pager's microcomputer.

According to yet another characteristic of the invention, the pager can also be made capable of comparing the message information received by the memory device with information previously stored. In this way, it suffices to store only message information which differs from the previously stored message information, which reduces the required storage capacity.

• la figure 1 est un schéma simplifié d'un mode de réalisation d'un pager suivant l'invention;
• les figures 2A et 2B montrent un diagramme représentant le schéma de codage POGSAG pouvant être utilisé pour la transmission de l'information de message destinée au pager de la figure 1;
• la figure 3 est un schéma plus détaillé du pager suivant l'invention;
• la figure 4 est un schéma simplifié d'un dispositif de mémoire utilisé dans le pager de la figure 1; et
• la figure 5 représente schématiquement une mémoire vive utilisée dans le dispositif de mémoire de la figure 4.

Other characteristics and advantages of the invention will appear during the description which follows, given solely by way of example and made with reference to the appended drawings in which:

• Figure 1 is a simplified diagram of an embodiment of a pager according to the invention;
• FIGS. 2A and 2B show a diagram representing the POGSAG coding scheme which can be used for the transmission of the message information intended for the pager of FIG. 1;
• Figure 3 is a more detailed diagram of the pager according to the invention;
• Figure 4 is a simplified diagram of a memory device used in the pager of Figure 1; and
• FIG. 5 schematically represents a random access memory used in the memory device of FIG. 4.

Referring now to Figure 1 of the accompanying drawings, there is shown a simplified diagram of a pager 1 constructed, by way of example, according to the present invention. This pager 1 comprises an antenna 2 to which is connected a receiver 3 intended to receive the coded message signals broadcast by a central station or by another source from which it is desired to call the user of pager 1. The message signals broadcast codecs may include, on the one hand, selective call signaling information to identify a pager particular among several or a large number of pagers conforming to FIG. 1 and, on the other hand, of the particular message information, the signals being able to be coded according to the POGSAG format or any other suitable coding format. The transmitted coded message signals received on the antenna 2 are demodulated by the receiver 3 and a serial binary data packet representing these coded message signals is supplied to an output 3a of the receiver 3.

The pager 1 also includes a decoder 4 connected to the output 3a of the receiver 3 by its input 4a. The decoder 4 comprises a memory area 4d intended for the storage of predetermined address information to which the pager 1 considered will respond. The decoder 4 is adapted to make a comparison between the coded message signals received at the input 4a and the predetermined address information stored in the memory area 4d. If the selective call signaling information corresponds to one of the stored addresses, the decoder supplies the message information proper associated with the coded message signals, at the output 4c of the decoder.

The pager 1 also includes an intelligent memory device 5 connected to the output 4c of the decoder 4 by its input 5a. This device 5 comprises a data processing unit 6 and a memory area 7 and it is suitable for receiving coded message signals on its input 5a and for storing these message signals in the memory area 7. The unit 6 data processing is adapted to control the manner in which these message signals are stored in the memory area 7 and extracted therefrom; it can also perform manipulations on message signals, addresses, pointers and other internal variables. The detailed operation of the intelligent memory device 5 will be described later.

The pager 1 also includes a microcomputer 8 connected to the output 5c of the intelligent memory 5 by its input 8a. The microcomputer 8 comprises, in a way known per se, a display interface 9, a microprocessor 10, a memory 11 with random access (RAM) and an area 12 of read only memory (ROM). The display interface is designed to display selected message information by controlling a display 13 via an input 13a and includes a serial driver and multiplexed serial drivers for liquid crystal display cell. This is adapted to display message information stored in the memory area 7 of the intelligent memory 5 and it can also be adapted to display the time or other information.

The ROM zone 12 contains, by construction, instructions for controlling the operation of the microprocessor 10, for example a program for the display of signs corresponding to the message information stored in the memory zone 7, for controlling the functions of input / output of the microcomputer 8, for supplying control signals intended for the intelligent memory 5 and for the decoder 4, and for controlling the time base of the microcomputer 8. The RAM area 11 is used for the temporary storage of data in the microcomputer 8 and provides, among other functions, a data buffer for the message information provided by the smart memory 5 and to be displayed.

The pager 1 also includes a circuit 14 of control inputs for applying, by an output 14a, data to an input 8b of the microcomputer 8, these data representing input information supplied by the user. User inputs 14b, c, d and e are connected to the control input circuit 14, these inputs being able to be in the form of pushbuttons, rotary knobs or other control members allowing the user to control certain functions of pager 1. The circuit 14 of control inputs can also be adapted to control other devices associated with pager 1. For example, a timepiece can be combined with pager 1 and the user inputs 14b, c, d and e can be used to provide certain commands for such associated devices. In addition, the control input circuit 14 can directly control certain functions of the timepiece associated with the pager 1, such as that of supplying the current to excite the motor 15 of an electronic clockwork movement. It should be noted that the pager thus combined with a timepiece may be in the form of a wristwatch.

A portable power supply 16 such as a battery is also provided in the pager 1 to supply, via the output 16a, energy to the input 3b of the receiver 3, to the input 4b of the decoder 4, to the input 5b of the intelligent memory 5 and at the input 8c of the microcomputer 8. Another portable power supply 17 provided with an output 17a is provided to supply energy to the circuit 14 of control inputs by the input 14f. The arrangement just described provides energy from separate sources respectively to the pager and its associated devices, such as a timepiece, so that if, for example, the pager's battery runs out, the timepiece can continue to operate. However, it is understood that the pager and its associated devices can just as easily be powered by a single energy source.

An example of message information and pager coding scheme used to broadcast message signals such as those used by pager 1, are shown in Figures 2A and 2B. The POGSAG system, well known to those skilled in the art, uses a digital coding format (FIG. 2A) composed of groups of code words 20, themselves each composed of a synchronization word 21 and a group 22 of eight frames of two code words each, these groups of code words being transmitted in a serial format at regular intervals. Each group 22 of eight frames is transmitted following a synchronization word 21, the eight distinct frames possibly containing either address information or message information. For the sake of explanation, Figure 2B shows that each frame has an address code word, 23.1 to 23.8 respectively, and a message code word, 24.1 to 24.8 respectively.

Thus, in the example represented in FIG. 2B, each pager of a group made up of pagers conforming to that represented in FIG. 1, must operate on one of the eight address code words so that each of these words represent signaling information with the help of which each pager of the group is respectively identified.

The invention will be better understood with reference to FIG. 3 which shows a more detailed diagram of a preferred embodiment of pager 1 according to the invention. As already described above, the pager 1 essentially comprises an antenna (not shown in FIG. 3), the receiver 3, the decoder 4, the smart memory 5 and the microcomputer 8. The circuit 14 for control inputs intended for controlling a timepiece 15 associated with the pager is also shown in FIG. 3.

The receiver 3 is connected by its terminal 3.1 to a positive supply conductor 16.1 of the portable energy supply 16 (not shown in FIG. 3), its terminal 3.2 being connected to a negative supply conductor 16.2 of the power supply 16. In a manner known per se, coded radio broadcast message signals are picked up and demodulated by the receiver 3 and the antenna to which it is connected, so that binary data packets such as those shown in the figure 2A, are generated at the output 3.3 of the receiver 3 and transmitted to the input 4.1 of the decoder 4. The receiver 3 comprises in its internal circuit an assembly (not shown in the figures and known per se) of monitoring of the voltage of the energy source 16, this circuit providing an indication signal of exhaustion of this source on the output 3.4 of the receiver 3. The output 3.4 transmits, if necessary, the signal of indication of exhaustion to other circuits of pager 1, so that a display readable by the user can be ensured on display 13.

The decoder 4 is connected to the positive supply conductor 16.1 by its terminal 4.4 and to the negative supply conductor 16.2 by its terminal 4.5. A voltage stabilizing capacitor 4d is connected between terminals 4.4 and 4.5. The decoder may be of the PCA 5001 type manufactured by Philips and its task is to separate the selective call signaling information from the message information proper in the coded message signals, and to compare the signaling information with the predetermined address information stored in the decoder and specific to the pager considered.

If the selective call signaling information corresponds to one of the stored addresses, any message code word following the relevant address code up to the next address word code is transmitted in the form of serial data. , from output 4.6 to input 5.1 of smart memory 5

The output 4.7 of the decoder 4 provides a data transfer signal to allow reading by the intelligent memory 5 of the data present on the output 4.6, this signal being able to take a high level or a low level at the input 5.2 of the memory. 5. The message information supplied at the output 4.6 is introduced into the memory area 7 of the intelligent memory 5, when a complete byte of data has been transferred from the receiver 3 to the decoder 4.

A resonator circuit 25 is connected to the decoder 4 via the inputs 4.8 and 4.9 of the latter. It essentially includes a 25a quartz resonator connected in parallel to a damping resistor 25b and to inputs 4.8 and 4.9. The positive supply conductor 16.1 is connected to one of the terminals of the quartz resonator 25a by means of a resonance capacitor 25c. The resonator circuit 25 cooperates with the internal circuit of the decoder 4 to form an oscillator circuit which supplies a periodic waveform of 32 kHz, for example to the decoder 4 to determine the rate of transmission of the message signals from the receiver 3 to the decoder 4. Of course, other clock frequencies can be used depending on the rate of transmission of the message signals. The resonator circuit 25 is also used to supply a clock signal to the microcomputer 8 and to the intelligent memory 5. This clock signal is supplied to the microcomputer 8 by the output 4.10 of the decoder 4. The values of the resistor 25b and capacitor 25c can be 4.7 MΩ and 10 pF respectively.

The decoder 4 comprises an electrically erasable reprogrammable memory of the EEPROM type (not shown) in which the system parameters of the decoder 4 are kept. Control signals can be sent from the microcomputer 8 to the inputs 4.11, 4.12 and 4.13 to control the functions of the decoder 4. One of the functions of the decoder 4 which can be controlled, is the rate of transmission of the bits between the decoder 4 and the intelligent memory 5, this rate can be as high as 5000 bits / sec. In this case, the message information is stored by the circular buffer located in the intelligent memory 5 without undergoing any other processing (such as the comparison between the last two messages which have just been stored).

The input 5.3 of the intelligent memory 5 is connected to the positive supply conductor 16.1, while the input 5.13 is connected to the negative supply conductor 16.2. The time base for the smart memory 5 is determined by the clock signal supplied by output 8.8 of the microcomputer 8 at input 5.4.

The intelligent memory 5 has four terminals 5.5, 5.6, 5.7 and 5.8 connected respectively to the corresponding terminals 8.1, 8.2, 8.3 and 8.4 of the microcomputer 8, which ensures a simple parallel connection with the latter allowing the sending of control signals from the microcomputer 8 to the intelligent memory 5 and the sending of message information stored in the memory area 7 of the intelligent memory 5 to the microcomputer 8 so that this message information can be displayed. Depending on the nature of the control signal sent, terminals 5.5 to 5.8 can also control the intelligent memory 5 to supply status information to the microcomputer 8 relating to the reception of message information by the memory 5. D other control signals can control it to manipulate message information stored therein, as will appear later. A data transfer input 5.11 from memory 5 is also provided for ensuring the simultaneous transfer of data to terminals 5.5 to 5.8.

An input 5.9 determines whether inputs 5.5 to 5.8 carry data or introduce control signals into smart memory 5. When a high level signal is present at input 5.9, the signals on inputs 5.5 to 5.8 are interpreted as being control signals from the microcomputer 8, while if a low level signal is present, the signals are interpreted as data.

A terminal 5.10 of the intelligent memory 5 makes it possible to indicate to the microcomputer 8 that it is ready to receive control signals from it. A high logic level signal on terminal 5.10 is interpreted by the microcomputer 8 as indicating that the memory 5 is ready for a new communication with the microcomputer 8, while a low level logic signal is interpreted to mean that the memory 5 is still in the process of either performing a manipulation on data or another operation, or of transferring data to the microcomputer 8.

An output terminal 5.12 of the memory 5 is used to supply an interrupt signal to the microcomputer 8 to indicate its functional state in response to received message information or to control signals. A signal of high logic level is sent to the microcomputer 8, if for example fresh or repeated message information is received, or if an unknown, prohibited or impracticable function is requested by the microcomputer. This interrupt signal can thus be used to indicate to the microcomputer 8 that a new operation is required, such as for example, the announcement of the arrival of fresh message information or the sending of a new one. smart memory command 5. A low level signal indicates that no new action is required by the microcomputer 8.

This microcomputer 8 can be of any known type, suitably programmed. It is connected to the positive supply conductor 16.1 by its input 8.5 and to the negative supply conductor by its input 8.6. An input 8.7 receives the clock pulse train from output 4.10 of the decoder 4. An output terminal 8.8 provides a clock signal to input 5.4 of the intelligent memory 5.

The microcomputer 8 also includes the output terminals 8.9 and 8.11 for supplying control and data transfer signals described above respectively to the inputs 5.9 and 5.11 of the intelligent memory 5, while the input terminals 8.10 and 8.12 are provided to receive respectively the acceptance and interruption signals described above from the intelligent memory 5.

A liquid crystal display 13 is connected to the microcomputer 8. It comprises segments numbered from 00 to 47 which are connected to the display driver circuit (not shown in FIG. 3) of the microcomputer 8 by a bus 13a so that each segment can be individually controlled and desired message information can be displayed by the display 13. Specialists will understand that various voltage values are required for the driver to control the various segments of the display 13. The input terminals 8.13 to 8.16 are connected to the positive supply conductor 16.1 via capacitors 8d to 8g to supply these various voltages. The capacitors 8d to 8g can have values of 220, 100, 100 and 100 nF respectively. The microcomputer 8 also comprises output terminals 8.17, 8.18 and 8.19 for supplying, in a manner known per se, control and time base signals to the display 13 coming from the driving circuit.

The input terminals 8.20, 8.21 and 8.22 are provided to stabilize and smooth the internal voltage levels of the microcomputer 8. One of the terminals of a capacitor 8h is connected to the input 8.20, while one terminals of another capacitor 8i is connected to input 8.21. The other terminals of capacitors 8h and 8i are connected together to terminal 8.22.

The microcomputer 8 is also provided with inputs 8.23 to 8.26 for control by the user, each of which is connected to the positive supply conductor 16.1 by means of switches 8j, 8k, 8l and 8m which can be actuated by the user. When this is the case, a signal of high logic level is applied to the control inputs by the user, for example when he wishes to turn on or off the pager 1, make it silent, protect the message displayed by the display 13 or delete a displayed message, as will be explained below. It will be understood that various other user-controlled functions may be provided in this manner and a separate input is not required for each of these functions so provided; for example, one or more switches or pushbuttons can be activated, in a particular sequence to indicate to the microcomputer 8 that a certain function must be performed.

The circuit 14 of the control and timepiece inputs is connected to the conductor 17.1 of positive supply of the portable supply 17 (not shown in FIG. 3) by the terminal 14.1 and to the negative supply conductor 17.2 of power supply 17 via terminal 14.2.

The circuit 14 also includes inputs 14.3, 14.4 and 14.5 which serve to constitute additional user inputs to allow the performance by pager 1 of certain functions to be controlled by the user, and also to control the operation of the timepiece 14 which is controlled by circuit 14. A particular sequence of signals applied to inputs 14.3, 14.4 and 14.5, or signals initially sent to other inputs, can be used to determine whether inputs 14.3, 14.4 and 14.5 control the operation of the pager or of the timepiece 15. The inputs 14.3, 14.4 and 14.5 are respectively connected to one of the terminals of the switches 14b, 14c and 14d, their other terminals being connected together to the input 14.1 . The switches can be made in any form usable by the user. Another switch 14e is connected between the positive supply conductor 17.1 and an input 8.27 of the microcomputer 8 in order to indicate to it whether the pager or the timepiece is being controlled.

The circuit 14 also has two outputs 14.6 and 14.8, connected respectively to one of the terminals of two coils 15a and 15b of the timepiece 15. The other terminals of these coils are connected to a connection return municipality 14.7. Specialists will understand that in the example chosen here, the coils 15a and 15b belong to a bidirectional motor of an analog quartz timepiece, moreover well known, but that a timepiece of any other type can be provided, including a digital timepiece, in which case, of course, a watch motor is not necessary. Various other inputs can be provided for circuit 14 to control any other function of the timepiece.

Two other outputs 14.9 and 14.10 of circuit 14 are connected respectively to inputs 8.28 and 8.29 in order to provide the microcomputer 8 with data representing the signals applied to inputs 14.3, 14.4 and 14.5. A quartz resonator 14.9 is connected to the input 14.11 and to the output 14.12 of the circuit 14 in order to constitute a time base for the latter.

The pager 1 also includes an alarm 26 coupled to the microcomputer 8 so that new message information received by the decoder 4 can be announced. An electric sound transducer 26a or "buzzer" is connected by one of its terminals to the collector of a switching transistor 26b and by its other terminal to the positive supply conductor 16.1. The collector of transistor 26b is also connected to output 8.31 of the microcomputer 8 via a bias resistor 26c which can have a value of 18 kΩ. Normally, this output is maintained at a high logic level. The emitter of transistor 26b is connected to the negative power supply conductor 16.2 and to terminal 8.6 of the microcomputer 8. The base of transistor 26b is connected to output 8.30 thereof. An inductor 26d with a value of 45 mH, for example, is connected in parallel to the buzzer 26a. Finally, a voltage stabilization capacitor 26e with a value of 4.7 μF, is connected between the positive 16.1 and negative 16.2 supply conductors. In normal operation, the output 8.30 is kept low and the transistor 26b is non-conductive.

When pager 1 has to announce the reception of a call or the accomplishment of another function, a signal which can have a variable waveform is sent by output 8.31 which generates a voltage across the terminals of buzzer 26a, which will thus produce a first sound. A different sound can be produced by the horn 26, when a signal is sent by the output 8.30 to the base of the transistor 26b which then starts to drive. A different voltage is then generated at the terminals of the buzzer 26a and a second sound is produced. These different sounds can be used to announce the accomplishment of various functions by pager 1.

FIG. 4 shows a simplified diagram of the intelligent memory 5 which essentially comprises the data processing unit 6, the memory area 7, the ROM 27, the stack of registers 28, the microprocessor interface 29 and the interface of decoder 30. The terminals 5.5 to 5.12, already described, are connected to the microprocessor interface 29, while the terminals 5.1 and 5.2, also already described, are connected to the decoder interface 30. The input providing the 32 kHz clock signal to the intelligent memory 5 is connected to the data processing unit 6. In addition, the microprocessor interface 29 includes a test input 5.13, a capacitor 5d which can have a value of 15 nF, being connected between the negative supply conductor 16.2 and an input 5.14 of the memory area 7.

The intelligent memory 5 also includes address and data buses 5e to 5k connected between the various internal elements of the memory 5 in order to be able to ensure communication and data transfer between them. The ROM 27 contains the programs necessary to operate the memory 5. In the embodiment described here, the memory area 7 is a RAM with a capacity of 512 bytes and intended to memorize the message signals from the decoder 4 and the internal system variables, the stack of registers 28 forming, on the one hand, a memory for the temporary storage of the data used to manipulate the message information stored in the memory area 7, and, on the other hand, the stack pointer and the program counter.

Specialists will understand that calls are normally transmitted more than once from a central station to a given pager to guarantee the security of good reception by this pager. Consequently, before writing the message information received from the decoder 4 to the memory area 7, the intelligent memory 5 can advantageously compare this message information received with the two previous messages that the pager has just received. If the new message information corresponds to one or other of these two most recent messages, the new message is not written to memory area 7.

As already indicated and as shown in FIG. 5, it is envisaged, in the embodiment of the invention considered, to give the memory area 7 a capacity of 512 bytes. Such a capacity is sufficient to give the pager 1 possibilities for manipulating the information which makes it comfortable to use.

A capacity of 512 bytes requires nine bits to allow addressing of bytes 0 to 511 of memory area 7. This means that for each write or read operation in this memory area, two transfers of eight bits each are necessary, because buses 5e to 5k have a transfer capacity of only eight bits at a time. The program stored in ROM 27 is suitable for working with such an eight-bit double transfer of which, in the present embodiment, only nine bits are used. In fact, it is therefore possible, without substantially changing the program contained in ROM 27, to easily increase the capacity of the memory area 7 up to a maximum of 65 kilobytes, which is a value far exceeding the capacity of 4 kilobytes which would already be a value giving great comfort in use. Such an expansion in memory capacity would give the pager the ability to perform more user-controlled functions and also a greater ability to store received message information.

The memory area 7 comprises address segments 7a, 7b and 7c (FIG. 5), whose segments 7a and 7b include the addresses 0 to 489 and are available for storing message information received from the decoder 4 and of which segment 7c comprises the addresses 490 to 511 and contain internal variables of the intelligent memory 5.

The address segment 7a includes the addresses 0 to 300 and it is used by the data processing unit 6 as a circular buffer to store the incoming message information from the decoder 4 so that the memory location assigned to the circular buffer is first sequentially filled with received message information. After storing message information at each available address in the circular buffer, the oldest message information is transferred when the most recent message information is received by smart memory 5. By default, the segment of address 7b occupying addresses 301 to 489 is used as a protection section in which is stored message information from the circular buffer which the user does not wish to have transferred.

The address segment 7c comprises the following addresses which are used by the data processing unit 6 to handle the data located in the memory area 7: Address Function 510 This memory location contains the address of the end of the last protected message located in the protection segment 7c. 508 Start address of circular buffer 7a or Top-Of-RAM (TOR). By changing the value stored in this memory location, it is possible to change the capacity of the circular buffer 7a. 503 This register contains a data value which determines the speed, in number of bytes per second, at which the data is transferred from the decoder 4 to the intelligent memory 5 without undergoing any processing or interpretation. 500 Contains the address of the last byte read, when the data processing unit 6 was executing the instruction "PFIN read decrement", described below. 499 The data stored at this address is used to determine which of the newly received message information will be compared with the previous two. This address is initialized with the data 01 Hex and can be transferred with the value 03 Hex when it is desirable to make such a comparison with the two most recent messages.

In addition, the following codes which can be stored in the memory area 7 are interpreted by the data processing unit 6 as having a particular meaning: Coded Meaning 08 Hex Beginning and end of protection zone 7b. 04 Hex, 84 Hex Header of a newly received message. 05 Hex, 85 Hex Header of a message to be deleted in the circular buffer 7a. 06 Hex, 86 Hex Header of a message that has been processed by the user of pager 1. 02 Hex, 82 Hex Header of a protected message which has been transferred from the circular buffer 7a to the protection zone 7b.

We will now describe the operation of the data processing unit 6 and the functions which are successively performed by the intelligent memory 5 when the various control signals are received from the microcomputer 8. As described above, the latter is capable of 'indicate to the intelligent memory 5 that it wishes to send a control signal by bringing the output 8.9 to a high level. When the output 5.10 is at the high level, a control signal present at the outputs 8.1 to 8.4 is read by the intelligent memory 5, when a logical transition from bottom to top occurs at the output 8.11. Under these conditions, the following functions can be performed by the intelligent memory 5, each function code representing the logic state of the outputs 8.4 to 8.1 respectively:

The following functions are used to read and write to memory area 7. The current address of memory area 7 at which the message information is to be stored or read, must first be placed in the PTA register. With a high logic level at the output 8.9 of the microcomputer 8, the data present at the inputs 5.5 to 5.8 are treated as control signals. The message information can then be transferred to the intelligent memory 5 or be extracted therefrom, when the logic level at the output 8.9 again takes a low level.

When a whole byte (two packets of four bits each) has been completely transferred, the position of the PTA pointer remains unchanged. Therefore, it is possible to copy an already read byte in RAM 7 without having to change the position of the PTA. It is only during the transfer of the first packet of four bits which are the most significant bits of the data, namely at the time of the appearance of the rising edge of the transition from bottom to top of the output 8.11, that the PTA will be increased or decreased and the address of RAM 7 to which it points, changed.

The following functions relate to a single complete message, instead of separate message information bytes comprising the message. To separate messages from each other, the 04 H or 84 H code is written with the data packet at the end of each message and at the start of the next message (header). The PTA must contain the address of the header of the message to be handled by the data processing unit 6 so that the following instructions can be executed. If the PTA does not contain this address, an interrupt signal is supplied by a high logic level at output 5.12, an error being found in the status word. Coded Function 0101 Change the header - a message is marked as having already been processed, by changing the byte at the start of the message to 06H or 86H. This can advantageously avoid a conflict between old message information and message information just received. 0110 Message protection - a message can be protected against a write fault by copying it to the protected area of address segments 7b. The message header in the circular buffer is first changed to 05 H or 85 H, then copied, byte after byte in the protected area. Then, the message is automatically deleted in the circular buffer 7a (no new code is necessary). 0111 Deleting a message - a message can be deleted from the circular buffer or the protected area. First, a message is marked for deletion by changing the header to 05H or 85H. It is then checked whether this message should be compared with new messages received by pager 1, in order to avoid the memorization of a repeated message. When the message can be deleted, all of its bytes will be deleted. If deletion is not immediately possible, the message remains marked and is deleted as soon as possible (but this requires a new delete command).

From the above, it can be seen that the intelligent memory 5 according to the invention is adapted to receive in real time message information from the decoder 4, to compare the message received with the messages previously received and to store selected message information in the memory area. The smart memory 5 is also capable of copying, deleting, moving or otherwise manipulating the stored message information and for communicating and exchanging information with the microcomputer 8 in such a way as this one be freed from the constraints related to the reception, storage and manipulation of message information.

Claims (14)

Pager for receiving broadcast coded message signals comprising call signaling information and message information, said message information comprising one or more messages, the pager comprising:
a receiver (3) for receiving and demodulating said coded signals,
a memory device (5) for storing said message information,
a decoder (4) intended to decode said coded mes sage signals to selectively deliver said message information to said memory device (5), and
function control means (8) intended to supply control signals to said memory device (5) and to receive stored message information therefrom,
said pager being characterized in that
said memory device (5) comprises internal processing means (6) intended to control the reception of said message information from said decoder (4). Pager according to claim 1, characterized in that said internal processing means (6) are arranged to control the reception of said message information directly from said decoder (4), independently of the control signals coming from said function control means (8 ). Pager according to one of claims 1 or 2, characterized in that said internal processing means (6) are also arranged to handle said message information stored in said memory device (5). Pager according to any one of the preceding claims, characterized in that said memory device (5) comprises memory locations forming a circular buffer (7a) in which is stored said message information from the decoder (4). Pager according to claim 4, characterized in that the number of memory locations in said circular buffer (7a) is adjustable. Pager according to any one of the preceding claims, characterized in that said internal processing means (6) are also arranged to compare the messages received by said memory device (5) and coming from said decoder (4) with messages previously stored . Pager according to claim 6, characterized in that each of said messages received from said decoder (4) is only stored in said memory device (5) if it differs from one or more previously stored messages. Pager according to any one of the preceding claims, characterized in that said memory device (5) comprises a protection zone (7b) with memory locations intended for the protection of memory information stored therein for protection against unauthorized replacement by message information subsequently received from said decoder (4), said internal processing means (6) being further adapted to write selected message information stored in said protection zone (7b) of said memory device (5). Pager according to any one of the preceding claims, characterized in that said internal processing means (6) are further adapted to delete message information stored in said memory device (5). Pager according to claim 9, characterized in that said internal processing means (6) are further adapted to delete message information contained either in said protection zone (7b) or in said circular buffer (7a) . Pager according to any one of the preceding claims, characterized in that said memory device (5) is arranged to receive said control signals from said function control means (8) and to provide it with message information, and in that said function control means (8) for this purpose comprise a parallel input / output (5.5, 5.6, 5.7, 5.8). Pager according to claim 11, characterized in that said parallel input / output (5.5, 5.6, 5.7, 5.8) is adapted to transfer four bits of data at a time. Pager according to any one of the preceding claims, characterized in that it further comprises at least one input (14b, 14c, 14d) which can be activated by a user to control its operation, in that a timepiece (14,15) is housed in the pager, and in that said input (14b, 14c, 14d) which can be activated by the user is also suitable for controlling the operation of said timepiece (14,15) Pager according to claim 13, characterized in that it is in the form of a watch strap.

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