FR2499258A1 - ELECTRONIC APPARATUS USABLE AS A DIGITAL CLOCK OR CHRONOGRAPH - Google Patents

Abstract

THE APPARATUS ACCORDING TO THE INVENTION INCLUDES AN OSCILLATOR 11, TWO MEMORIES 12, 13 TO STORE AND UPDATE THE DATA RELATING RESPECTIVELY TO REAL TIME AND TO THE MEASURED TIME, A DISPLAY UNIT 17, SELECTION MEANS 120 DESIGNED TO TRANSMIT SELECTIVELY AT THE DISPLAY UNIT 17 THE DATA CONTAINED IN MEMORIES 12, 13 AND SEVERAL BUTTONS 1, 2, 3, 4 OF WHICH AT LEAST A FIRST BUTTON IS DESIGNED TO SET MEMORY 12 TO TIME AND TO COMMAND THE MEANS SELECTION 120, WHILE A SECOND, A THIRD AND A FOURTH PUSH-BUTTONS ARE DESIGNED BOTH TO CONTROL THE SETTINGS OF MEMORIES 12, 13 AND TO CONTROL THE SELECTION MEANS 120. THIS APPLIANCE CAN BE ADVANTAGEALLY MOUNTED ON A MOTOR VEHICLE.

Description

Electronic apparatus usable as a digital clock

or chronograph.

  The invention relates to an electronic device that can be used as a clock and / or chronograph with digital time indication. The apparatus according to the invention can advantageously be mounted on a motor vehicle to enable the driver to read continuously the real time and at the same time, to make an accurate measurement of the

  the time taken by the vehicle to travel a distance

completed.

  There are many electronic devices

  above type which are currently commercially available and which are specifically intended for use in

  the automotive field. For example, there are

  They are able to give real time in the form of hours, minutes and seconds and the measured time as hours, minutes, seconds and tenths of a second. Since minimal energy absorption is necessary in order not to consume a percentage

  considerable amount of battery current, use is made of

  tagged the same group of display elements, by

  example of the seven-segment type, to display the figures

  related to both real time and measured time

  re. For this purpose, there are provided push buttons to allow to choose at any given time the desired function and also to adjust at the exact time the part

  of the device which concerns the real time.

  Given the large number of functions that may be required of such devices and the impossibility of associating a push button with each function, the

  for reasons of space and for

  driver has no difficulty in learning the function-

  a small number of pushbuttons are used

  that we operate in different combinations to choose

  air the desired function at any given time. Unfortunately

  Currently, the function setting (for example, the transition from real time to the measured time, starting -2 - or stopping the counter, resetting the counter, etc.) is carried out with the same functions. Pushbuttons used to set the device to the correct time. This fact leads at first to a certain difficulty in learning and remembering the operations required to perform the functions and may also inadvertently

  an unintended change in the actual time indicated.

  The object of the invention is to provide an electronic device that can be used as a digital clock and / or chronograph, which can be conveniently mounted on a motor vehicle and free from the aforementioned drawbacks.

known devices.

  The above object is achieved, according to the invention, by an electronic device intended to serve as a clock and / or chronograph with numerical indication and characterized in that it comprises an oscillator, a first and a second memories designed for

  memorize and update relative data

  in real time and measured time, a digital display unit, selection means adapted to selectively transmit to the display unit the data contained in the memories, and several

  pushbuttons including at least a first button

  pusher is exclusively designed to set the exact time the first memory and to control the selection means, while a second, third and fourth push buttons, or individually,

  in combination, are designed both to control

  der the setting of the first and second memories

  and to control the selection means.

  The invention will appear better in the description

  of a preferred embodiment, given below, by way of non-limiting example, with reference to the appended drawing in which:

  The single figure is a diagram of the electrical circuit

  than an apparatus according to the invention.

  In the drawing, the reference 10 generally indicates an apparatus usable as a clock and / or chronograph on a motor vehicle and essentially comprising an oscillator 11, two memories 12, 13 which receive, respectively directly and via an AND gate 14, an output signal generated by the oscillator 11, and a selective combiner network 15 which receives the output signals generated by the memories 12 and 13 and selected by means of a switch unit

  16 and brings these signals to a digital display unit.

  17 essentially consists of four seven-segment indicator elements 18a, 18b, 18c, 18d and two light-point indicator elements 19b, 19d, respectively arranged below the elements to be shown.

  seven corresponding segments 18b, 08d.

  The memory 12 is of known type and essentially comprises several memory cells (no

  represented) each of which contains digital data

  relating to real time, that is to say numbers which distinguish the day, the month,

  the hours, minutes and seconds of the real time.

  The memory 12 comprises inputs 21, 22, 23, 24

  respectively related to the outputs of the AND logic gates 25, 26, 27, 28 of which they are intended to receive positioning signals relating to the contents of the memory cells in which the data relating to the number corresponding to the day, to the month, to the hours and minutes. The memory 12 also comprises a start input 29 for counting the real time and setting the content of the second cell to zero, this input being connected to the negative output & of a

  bistable, arming and resetting multivibrator 30.

  Finally, the memory 12 comprises an input 31 o is constantly present a signal with a frequency of 1 Hz and which is connected to a first input of a logic gate AND two inputs, 32. The output of the memory 12 of which actual time signals are indicated by 34 and parallel to each other relative number data which distinguishes the day, month, hours and minutes of the actual time. Likewise, the output of the memory 13 o are present. The signals relating to the measured time are indicated by 35 and carry several data relating to the

  numbers indicating respectively the hours, the minutes

  seconds and seconds of the measured time, advantageously up to a maximum value of 9 hours. 59 minutes

  59 seconds. Memory 13 presents indi-

  A logic level signal "1" is available when the contents of the memory cells are in the order of minutes and seconds or the order of hours and minutes, respectively. The memory 13 also comprises an output 38 o a level signal

  logic "1" is available when the content of the

  moire is 9 hours 59 minutes 59 seconds. The output 38 is connected to a first input of a logic OR gate with two inputs 39 whose output is connected to the input

  resetting 40 of the memory 13.

  The selective network 15 comprises several activation inputs designated respectively by 41 to 49 and each of which is connected to the output of a respective logic gate indicated by a corresponding number of 51 to 59. All the logic gates of the latter group are type AND except the logic gate 56 which is

  type OR. More specifically, the selective network 15 trans-

  the following: when the signal present at the input 41 is at logic level "1", it transmits to the display elements 18k, 18k the digits of the number relative to the day of the

  real-time and to the bright-point element 19b, a

  continuous feed pattern; when the input 42 is at logic level "1" n, it transmits to the display elements 18c, 18d the digits of the number relative to the month and to the point element 19b, a continuous signal; When the input 43 is at level "1", it transmits

  to the display elements 18k, 18b the numbers of the

  the hours and point element 19b, an intermittent signal; when the input 44 is at the level "n1, it transmits

  to the display elements 18c, 18d the numbers of the

  relative to minutes and point element 19b, an intermittent signal; when the input 45 is at the level "1" n, it transmits to all the display elements of the set 17 the numbers of the numbers relating to the hours and minutes and to the point element 19b, a signal of continuous feeding; when input 46 is at level ln, it transmits a continuous supply signal to all segments

  display elements 18 and to the two light elements

  19; when the input 47 is at the level "n1", it transmits to all the display elements 18 of the set 17 the numbers of the numbers relating to the day and to the month (without

  zeros on the left if the represented number is formed only

  units) and to the point element 19D, a continuous supply signal; when the input 48 is at level "1", it transmits the numbers of the numbers relating to the minutes and seconds of the measured time and to the point element 19d, a supply signal, and - when the input 49 is at level "1", it transmits the numbers of the numbers relating to the hours and minutes of the measured time and to the point element 19d, a

signal of feeding.

  The apparatus 10 also comprises four pushbuttons respectively indicated by the numerals 1, 2, 3, 4 and by means of which the behavior of the apparatus 10 can be controlled. The pushbuttons 1; 3 and 4 have a first terminal connected directly to a terminal 5b of a switch 5 and to a terminal of a resistor 7 - 6 -

  whose second terminal is connected to the earth. The button-

  pusher 2 has a first terminal connected to the cathode of respective diodes 8, 9, the anode of the diode 8 being

  connected to terminal 5b and the terminal of resistor 7.

  The switch 5 is advantageously the switch which, in the aforesaid motor vehicle, is controlled by the ignition key so that it is open or closed, respectively, depending on whether the key is removed or brought

  rotation to the pre-ignition or start-up

  rage. The second terminal 5a of the switch 5 is

  connected to a terminal 6 which is unrepresented

  sent to a DC power source such as the vehicle battery. This terminal 6 is also connected

  permanently to the power input of the oscillator

lateur 11.

  The second terminal of the push-button 1 is connected to earth via a resistor 61, upstream of a cyclic module counter 5, 62, and via a logic gate NO, 63, resetting input R of a bistable multivibrator 64. The input

  armature S of the multivibrator 64 is connected to the rod

  two branches of a delay network RC, 65, of which a first branch consists of a resistor 66 connected to the terminal 6 and the second branch by a resistor 67 and a capacitor 68 which are connected to each other in parallel and to Earth. The non-inverting output Q of the multivibrator 65 is connected to the second input of the AND gate 32 whose output is connected to a

  first entrance to the door OR 56.

  The cyclic counter 62 has five outputs indicated by 71, 72, 73, 74, 75 and each of which is respectively connected to a first input of the AND gates 51, 52, 53, 54, 55, to a first input of the gates.

  ET 25, 26, 27, 28 and at the reset input R of the multi-

  bistable vibrator 30 via a logic gate NO 96. The arming input S of the multivibrator

  is connected to the exit of the AND gate 28 through

2 499258

  The second input of the AND gates 25, 26, 27 and 28 is connected to the output of a logic OR gate with three inputs, 80. The first input of this gate 80 is connected respectively to a first input of a two-input OR logic gate 81, to the first input of a three-input AND gate 82, to a first input of a two-input AND gate 83, to the second terminal of the pushbutton 2 and to the ground via a resistor 84 and a capacitor 85 connected in parallel. The second input of the OR gate 80 is connected to a second input of the AND gate 82, to a first input of an AND gate

  two inputs 86, a resistor 87 and a capacitor

  88 connected in parallel and connected to the earth

  and, through a resistance 89, to the second

  x terminal of the push-button 3 and at a first input of a logic AND gate with two inputs 90. The

  third input of the OR gate 80 is respectively connected

  at the third input of the AND gate 82, at the second input of the AND gate 90, at the first input of a two-input AND gate 91, at the second terminal of the pushbutton 4 and at the ground by the intermediate of a resistor 92 and a capacitor 93 connected in parallel with each other. Every second entrance of the doors

  ET 86 and 91 is connected to output 75 of the cyclometer.

  62 and at a first input of a two-input OR gate 95 whose output is connected to the second input of the AND gate 83. The output of the AND gate 82

  is finally connected to the second entrance of the OR gate 56.

  The terminal 5b of the switch 5 is connected to the second input of the OR gate with two inputs 81 whose output is connected to a first input of a door

  AND two entries 97. The second entry of this

  is connected to the exit of the gate NO 98 and its exit is connected to a second entrance of the doors

  AND 51, 52, 53, 54, 55 and 57. The terminal 5b of the interrup-

  5 is also connected, via a logic gate NO 99, to the anode of the diode 9, to the second input of the OR gate 95 and, via a logic gate NO 100, at a first entry of a

  AND logic gate with two inputs 101.

  The output of the AND gate 83 is connected to the second input of the AND gate 101 and via a delay network 103 consisting essentially of a series resistor 104 and a resistor 105.

  and a capacitor 106 connected in parallel, to a first

  first input of an OR gate 107 and, through a NOR gate 108, to a third input of the AND gate 55. The output of the AND gate 101 is connected to the second input of the OR gate 107 which the exit is

  connected directly to the second entrance of the door -

  AND 57 and, through a NO 109 gate, to the

  fourth entrance of the AND gate 55.

  The outputs of the AND gates 86 and 91 are respectively fed to the first inputs of AND logic gates with two inputs 111, 112 whose second input is connected to the output of the AND gate 90. The output of the latter is also connected to the second input of the OR gate 39. The output of the NAND gate 111 is connected to the input of a bistable multivibrator 113 whose output is connected to the input of the NOR gate 98, to a first input of the logic gates 58 , 59 and at the input to control the position taken by the switch 16. The second input of the doors 58 and 59 is connected

  respectively at the outputs 36 and 37 of the memory 13.

  The output of the NAND gate 112 is connected to the input of a bistable multivibrator 114 whose output is connected to the second input of the AND gate 14. The network, the switch 16, the cyclic counter 62, the

  multivibrators 113 and 114 and the various logic gates

  described so far constitute as a whole

  a selection network 120 controlled by the buttons

  pushers 1, 2, 3, 4 and designed to transmit selectively

  to the display unit 17 the data contained -9-

in the memories 12, 13.

  The operation of the apparatus 10 is described below.

  after, the examination of this operation consisting of the following stages: A) Connect the apparatus 10 to the power supply; B) Set the memory 12 to the correct real time; C) Examine the functions performed by the appliance when the ignition key is inserted (switch 5 closed). D) Examine the functions performed by the appliance when the ignition key is removed (switch open).

STAGE A

  When the apparatus 10 is connected to the power source

  tation, the arming input of the bistable multivibrator 64 is maintained for a few moments at logic level "0", then goes to logic level "1" when the capacitor 68 of the delay network 65 is fully charged. As a result, the output Q of the multivibrator 64 is set to logic level "1" so that the gate 32 becomes able to let the 1 Hz signal, which exists at the output 31 of the memory 12, arrive at the first input of the OR gate 56. Therefore, the latter transmits to the input 46 of the selective network 15 a signal which is alternately at the level "1" and "0" and on the basis of which all the segments of the elements 18 and the two luminous elements 19 of the display unit 17 are

  electrically fed intermittently and therefore

  gnotent. The display unit 17 therefore indicates to the driver that the real-time memory 12 is not set correctly. The aforementioned flashing stops only at the beginning of stage B of adjustment of the

  memory 12, this stage being the following.

STAGE B

  Before describing how to operate

  push-buttons 1, 2, 3 and 4 to adjust the

- 10 -

  12, it should be noted that the apparatus 10 is provided with initial positioning circuits (reset), no

  represented, thanks to which, when

  5, the output of the multi-vibrator bistable 113 is set to logic level "0", resulting in a positioning of the switch block 16 as shown in the drawing. In addition, the output 75 of the cyclic counter 62 is set to logic level "1" while the outputs

  71, 72, 73, 74 of this counter are at logic level "0".

  The memory 12, relating to the day, to the month, to

  hours and minutes respectively, is set

  a cycle comprising four consecutive stages for

  each of which we start by pressing the button

  push 1, this operation showing, on the display unit 17, the respective numbers relating to the day, month, hours and minutes of the actual time to be adjusted. If necessary, then any one of the push-buttons 2, 3, 4 is actuated in order to bring a correction signal to the contents of

  this memory cell 12, displayed at this time.

  More particularly, the first actuation of the

  push button 1 has the effect of

  at the logic level "1", for the first time, the input of the cyclic counter 62 and to

  logic level "0" the reset input R of the multivariable

  The output Q of the latter therefore goes to logic level "0" and remains at this level, thus preventing the gate 32 from bringing this activation signal to the OR gate 56. Simultaneously, the signal present at the output 71 of the cyclic counter 62 is set to logic "1" so that through the AND gate 51, a logic level signal "1" is brought to the input 41 of the selective network 15. The signal at the logic level "1" present at the output 71 passes through the gate 51, since the other input of this gate is at the logic level "1", because the two inputs of the AND gate 97 located downstream of the AND gate 51 are at logical level "1". AT

- 11 _

  In this respect, the first entry is connected through

  OR gate 91 to the positive terminal 5b of the switch 5 and the second input is connected to the output of the gate 98 which is also at the level "1" 1 because the input of the latter is maintained at the level of "0" by the signal present at the output of the bistable multivibrator 113. Because of the foregoing, the elements

  18a, 18b of the display unit 17 display the figures

  fres the number corresponding to the real-time day contained in the memory 12, while the bright-point element 19b is kept constantly lit. In these

  conditions, by acting on any of the buttons

  pushers 2, 3 or 4, a signal is provided at the logic level

  that "l", through the OR gate 80, to the input 21 of the memory 12 through the AND gate 25. In this regard, the latter is activated since it has an input connected to the output 71 (at logic level "1" n) of the cyclic counter 62. If any of the pushbuttons 2, 3 or 4 are held down, an activation signal is thus transmitted to the memory cell 12. relating to days. The contents of this cell are, for example, updated with a frequency of 1 Hz according to a known type of system until the number corresponding to the jiur to be set appears on the display unit 17. is only necessary to release button 2, 3 or 4 so that this number remains in memory 12 and it is

  then automatically updated, according to a prede-

  completed, based on the signal generated by the oscillator

11.

  The contents of the memory 12, relating to the months and to the hours, are regulated by an operation similar to that described above, that is to say by first actuating the push-button 1, and then, one any

buttons 2, 3 or 4.

  The number relative to the minutes is also regulated in a similar way. More specifically, when

- 12 _

  actuates the push button 1, the output 74 of the cyclic counter 62 is set to logic level "1", thereby allowing the digits relating to the minutes of being displayed on the display elements 18c and 18d via the selective network 15 , the light point 19b pulsating at a frequency of 1 Hz. If the button 2, 3 or 4 is then actuated to correct the minute digit contained in the respective cell of the memory 12, a signal at the logic level "O" is brought in passing

  by the gate NO 78, at the arming input S of the multi-

  Bistable vibrator arming and reset 30. The output of the latter is set to logic level "O0" and causes a blocking signal to the activation inputs 29 of the memory 12, so that the counting within the memory 12 stops and at the same time, the contents of the memory cell relative to the seconds is reset to zero. Under these conditions, the contents of the memory 12 are not updated and thus, the clock remains stopped until, by pressing the button 1 again, the output 75 of the cyclic counter 62 is set to logic "1". Under these conditions, the inverted output Q of multivibrator 30 is reset to logic level "1", via gate NO 96, so that memory 12 is unblocked and the counting of real time begins, the seconds being at

  zero. At the same time, exit 75 causes both the

  recording the numbers of the hours and minutes numbers on the display unit 17 (input 45 to

  logic level "1") and the intermittent ignition of the

  luminous point 19b. Stage B relating to the correct setting of the time is thus completed. The push button 1 does not need to be activated yet, except to correct again the contents of the memory 12 relative to the real time.

STAGE C

  As has been said, during this stage, the behavior of the apparatus 10 is examined when the key is inserted.

- 13 -

  starting and that the pushbuttons 2, 3 or 4 are actuated in the various combinations described below. It will first be assumed that none of the buttons are pushed and that the memory 12 has been correctly set, so that the display unit 17 displays the hours and minutes digits as indicated above. This is possible since all inputs to AND gate 55 are at logic level "1". In this respect, from the top, the first input is maintained at the logic level "1u by the output of the AND gate 97 as already mentioned, the second input is maintained at logic level" 1 "by the signal present at the output of the cyclic counter 72, the third input is maintained at the logic level "1" by the output of the NO gate 108 (the input of the latter is maintained at the level "O0" because it is controlled by the output of the AND gate 83, the input of which is maintained at the logic level "Off by resistor 84"; the fourth input of the AND gate 55 is maintained at logic level "1", by the output of the NOR gate 109 (the input of the latter is kept at "0" by the output of the OR gate 107 whose two inputs are both at the level

  logic "0" because of the above). We can easily

  Check that with the exception of input 45, all enable inputs 41 to 49 are kept at logic level "O". Therefore, under normal conditions and when the key is inserted, the driver sees the time in the form of hours and minutes on the display unit 17, the point indicating element

  flashing light has a frequency of 1 Hz.

  It will now be assumed that, with the key inserted, the button 2 is pushed. A signal at the logic level "1" is instantaneously presented at the input of the AND gate 83 which, since there exists at its other input a signal at logic level "1", instantly switches

  own output from "0" to "1", which leads to the

- 14 -

  instantaneous signal present at AND gate 101, OR gate 107, NOR gate 109, AND gate 55 and AND gate 57, in that order. In the selective network 15, the signal present at the input 47 thus goes to logic level "1", which causes the indication unit of the display unit 17 to switch, which now gives the numerical indication of the day and of the month, an interposed continuous light signal being presented by the light-point element 19b. If resistance and

  respective capacity of resistance 84 and

  85 are suitably selected, it is possible to maintain the capacitor 85 charged for a few seconds, for example 5 seconds, after the button 2 has been released. In this way, the present signal

  at the entrance of the AND gate 83 is kept artificially

  level "1". The switching of the output of the AND gate 83 to "O", which follows obligatorily, does not yet switch the AND gates 55 and 57 because the

  capacitor 106 must still be discharged by the resistance

  When the latter capacitor is discharged, the logic level is switched to "0" for the input signal, both of the NOR gate 108,

  switching to "1" level of the output signal corresponding to

  and the OR gate 107, which has the effect of switching the corresponding output signal to logic level "0" and switching the NOR gate 109 and the AND gate 57. Consequently, a new change occurs. snapshot of the signals present at the inputs

  and 47, so that the apparatus 10 again starts to indicate the real time in the form of hours and minutes. If the resistor 84 and the capacitor 85, as well as the resistor 105 and the capacitor 106, are of appropriate size, it is possible to determine a specific amount of time after which the data display automatically switches to the time display.

  real, when we insert the boot key.

  We now assume that the push button 3 * e

- 15 -

  is depressed for a time exceeding a predetermined minimum quantity, for example 0.5 seconds, in order to give the capacitor 88 the time to charge to a level sufficient to generate a signal at the logic level "1" at the input of the AND gate 86, a logic level signal "1" is then transmitted from the output of this gate to the input of the NAND gate

  111. Since this one has another output

  held at the logic level "1" by the output signal of the NAND gate 90 because the button 4 is not depressed, there is therefore a switching of the output signal of the NAND gate 111, the logic level " 1 "at the logic level" O ". This switching from "1" to "O"

  causes a switching of the output signal of the multivariate

  bistable brator 113, which therefore goes from "on to" 1 ", and therefore switches the inputs 41, 42, 43, 44, 45 and 47 of the selective network 15 to the logic" O "through the gate NO 98 and the AND gate 97, while switching the input of the AND gates 58 and 59 connected thereto to the logic level "1", or the output 36 or the output 37 of the memory 13 are at the logic level "1", according to the content of the memory 13 with respect to the measured time so that a corresponding display of the time measured on the display unit 17 occurs in the form of minutes and seconds or hours and minutes.

  Similar to what has been described, the

  The actuation of the push-button 4 has the effect of instantaneously switching the signal present at the output of the NAND gate 91 and consequently also at the output of the NAND gate 112, with instantaneous switching of the output signal of the bistable multivibrator 114 which spends

  logic level "10" at logic level "1". From this

  However, the signal generated by the oscillator 11 can be

  transmitted to the signal input of the memory 13 in step-

  through the AND gate 14 so that the count of the time measured by the memory 13 begins. This one is

- 16 -

  of dimension such that, as long as the count is less than one hour, the signal present at the output 36 is at logic level "1", after which the signal present at the output 37 is maintained at the logic level "1", of so that initially the minutes and seconds are indicated by the display unit 17, followed by the hours and minutes. When the total counting capacity of the memory is reached, the signal present at the output 38 is switched to "1" and is immediately returned to the

  memory 13, passing through the OR gate 39.

  This signal is fed to the reset input, so that after reaching 9 hours 59 minutes 59 seconds, the contents of the memory 13 change to O hours.

O minute O second.

  When the button is pressed a second time

  push button 3 or 4, the output signal present at the output of the bistable multivibrator 113 or 114 is switched again, so that if the button 3 is pressed, the mode switches to real time, whereas if the button is actuated 4, the count of measured time stops. With regard to the latter case, the light signal generated by the point element 19d pulses at a frequency of 1 Hz during the counting stage, whereas when the chronograph is stopped, the light signal is constantly lit to indicate that the

Chronograph does not work.

  If now, buttons 3 and 4 are pressed simultaneously, only the signal present at the exit of the door

  NO AND 90 switches from logic level "Ot" to logic level

  only "1". In this case, the contents of the memory cells 13 are reset because a signal at the logic level

  "1" reaches entry 40 through OR gate 39.

  If, however, the three buttons 2, 3, 4 are simultaneously actuated, a signal at the constant logic level "1" is transmitted to the input 46 of the selective network 15 and therefore all the segments of the display elements 18a, 18b , 18c, 18d are activated at the same time as the elements

- 17 -

  light point indicators 19b, 19d. The sole purpose of this test is to check the efficiency of the display unit 17 when the ignition key is inserted,

  that is to say when the switch 5 is closed.

STAGE D

  When the key is removed, the only pushbutton still active is button 2 because it is still powered at its positive terminal by the output of the gate 99. If the button 2 is not actuated, the two inputs of the OR gate 81 are maintained at the level

  logic "0" through the respective resistors

  7 and 84 so that no element of the unit

  display 17 is electrically powered.

  When button 2 is actuated, the signal present at input 45 dd selective network 15 is instantaneously switched to logic level "1" because a signal at logic level "1" is brought to the input of the gate OR 81 and that by combining with the logic level signal "1" present at the output of the gate NO 98, it switches

  at logical level "1" the output of the AND gate 97.

  On the other hand, it should be noted that the other inputs of the AND gate 55 are already at logic level "1". In this respect, input 75 must be considered as being at logic level "1", since it assumes that the apparatus 10 is not adjusted at the correct time and that the other two inputs of the gate 55 are at the "1" level. because the input of the NOR gate 108 is temporarily held at "t0" by the capacitor 106 which also maintains at the "O" level the input of the OR gate 107. Since the other input thereof is kept at "0" by the output signal present at the gate 108 (thanks to the gate NO 100), the output of the OR gate 107 is also at the logic level "O", and consequently, it makes the logic level "O" the entrance of the AND gate 57, and,

  corresponding way, puts at logical level "1" the

  third input of the AND gate 55 through the gate NO 109. However, if the button 2 is held down,

- 18 -

  the capacitor 106 charges until, after a predetermined period of time, for example 2 seconds, it causes the switching of the signal present at the inputs of the NOR gate 108 and the OR gate 107 of which a signal at the logic level "O" is brought to the input of the AND gate 55 and a logic level signal n1 "is brought to the input of the AND gate 57. The output of the latter therefore switches to the logic level" 1 " , thus enabling the date to be displayed in the form of the day and the month via the selective network 13,

  the bright-point element 19b being constantly lit.

  When button 2 is released, the initial conditions

  are recovering after a short period of time,

  the display unit 17 being extinguished.

  Examining the characteristics of the device 10

  according to the invention shows that it achieves the specific

  fied. First, it allows real time and measured time to be read in a comprehensive way that suits the

  better to the needs of the motor vehicle driver.

  In this respect, it can provide the date in the form of the day and the month, the actual time in the form of hours and minutes, and the measured time in the form of hours, minutes, and seconds. a maximum of 10 hours, this time being more than sufficient to determine

  the time used to travel a given distance.

  Each push button has a specific function and it is difficult to confuse them. Advantageously, the pushbuttons 2, 3 and 4 could be in the unobstructed position, whereas the button 1 serving only to correctly adjust the real time could be placed

  in a less visible position, at the same time, for the dis-

* tapping other pushbuttons and to prevent

  the driver does not operate it by mistake while driving.

  So, although the number of functions performed

  by the apparatus 10 is much higher than that of

  analogous commercial standards, it is advantageous

- 19 -

  simpler to operate and does not require painfully remembering the operations required to obtain

  all the information he can provide to the driver.

  Finally, it is obvious that modifications can be made to the described embodiment of the apparatus

  without departing from the scope of the invention.

  For example, the sequence used to adjust the time

  correct could be different from the one we have described.

  We could stop the blinking of the display unit

  chage 17 when establishing the power supply

  by pressing any of the buttons from 1 to

  4, and not especially the button 1 as described.

  Actuation of the button 1 for the first time after the power supply has been established could still cause the same day of the month to be displayed on the display unit 17, in which case the memory 12 would be

  equipped with an automatic reset.

  The date could advantageously be written in the form of the month and the day, instead of the day and the month

  as described. Similarly, the real time could be cal-

  either in the twelve-hour system (American system) or in the twenty-four hour system (European system). Other modifications are possible

in the context of the invention.

- 20 -

Claims (14)

  1.- Electronic apparatus for use as hor-   housing and / or chronograph with numerical indication and characterized in that it comprises an oscillator (11), a first and a second memory (12, 13) designed to store and update data   relating respectively to real time and measured time   a digital display unit (17), selection means (120) for selectively transmitting to the display unit (1: 7) the data contained in the memories (12, 13), and a plurality of push buttons (1, 2, 3, 4) at least one first push button is exclusively designed to set the exact time the first memory (12) and to control the selection means (120) while a second, a third and fourth push buttons, either individually,   in combination, are designed, at the same time, to control   der the setting of the first and second memories   (12, 13) and to control the selection means (120).   2. Apparatus according to claim 1, characterized   in that the selection means (120) comprise   a cyclic counter (62) which receives a control signal from the first push-button (1) and supplies to the first memory (12) a selective signal designed to determine the setting of a predetermined cell of that memory, this signal selectively being fed to the activation inputs of a selective network (15) through which the contents of the predetermined memory cell are fed to the display unit (17) .-   3. Apparatus according to claim 2, characterized in that at the end of the adjustment stage of each of the memory cells, the cyclic counter (62) is   designed to bring, following the receipt of a   control signal from the first button (1), a boot signal to start the count, in the first   memory (12) of a signal generated by the oscillator (11). _ 21 -   4. Apparatus according to claim 3, characterized in that when the counting has started in the first memory (12), the boot signal generated by the cyclic counter (62) has the effect that the contents of memory cells relating to the corresponding figures   hours and minutes of real time is trans-   put to the display unit (17) via the network selective (15).   5. Apparatus according to claim 4, characterized   in that any actuation of the second button   push button (2), when the count has been started in the first memory (12), has the effect that the contents of cells of the first memory (12) relating to the digits corresponding to the day and the month of the real time, is transmitted to the display unit (17), via the selective network (15), for a period of time of predetermined duration, at the end of which the transmission of the figures relating to the hours and minutes of the time real is recovering.   6. Apparatus according to one of claims 1 to 5,   characterized by the fact that any actuation of the third   sth pushbutton (3) has the effect of switching the data presented by the display unit (17) so that the data contained in the second memory (13)   displayed if the data contained in the first   first memory (12) have been displayed previously and vice versa. 7.Apparatus according to claim 6, characterized in that the third push button controls   positioning a switch (16) designed to receive   see the signals related to the data from the first   first memory (12) or the second memory (13) and to bring this data to the display unit (17)   through the selective network (15).   8. Apparatus according to one of claims 1 to 7,   characterized by the fact that any actuation of the   third push button (4) alternately causes the - 22 -   starting and stopping the transmission of the oscillator signal (11) to the second memory (13), in that which concerns the measured time.   9. Apparatus according to one of claims 1 to 8,   characterized by the fact that any simultaneous actuation of the third and fourth push buttons (3, 4) causes a complete reset of the second memory (13).   10. Apparatus according to one of claims 1 to 9,   characterized in that it comprises a third memory (64) which, when the apparatus is connected to a power source, leads to the selective network (15) a   control signal which results in an inter-   suspending the digital display unit (17).   11. Apparatus according to one of claims 1 to 10,   suitably mounted on a motor vehicle and characterized in that each of the pushbuttons (1, 2, 3, 4) is connected to the downstream side of a switch (5) whose actuation is controlled by the position taken by the ignition key of the vehicle and which, in the closed position, supplies each of the push-buttons (, 2, 3, 4).   12. Apparatus according to claim 11, characterized in that it comprises logic means (99) which maintain the second button (2) powered even when the switch (5) is open.   13. Apparatus according to one of claims 11 and   12, characterized by the fact that when none of the buttons   (1, 2, 3, 4) is activated and at the same time   switch (5) is open, the selective network (15) does not   no power signals to the display unit (17).   14. Apparatus according to one of claims 12 and   13, characterized in that any actuation of the button (2), when the switch (5) is open, has the effect that the contents of memory cells (12) relating to the numbers corresponding to the hours and   minutes of actual time is transmitted to the display unit. - 23 -   display (17) for a first period of time and that the contents of the cells of the first memory relating to the digits corresponding to the day and the month are transmitted to the display unit (17) for a second lapse of time which follows.