JPH0820887B2 - Circuit arrangement for actuating a load using a microprocessor - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a circuit device according to claim 1.

2. Description of the Related Art The use of microprocessors has been popular in all technical fields in recent years, and microprocessors are frequently used in automobiles, for example. Also, the microprocessor is
It is used not only for sequence control of various processes in a predetermined manner, but also for operating loads such as control lamps and electric motors.

A problem with the known use cases of microprocessors is that during the desired actuation and display of the load, the load normally outputs two electrical terminals (pins) or the output of the microprocessor to perform the desired functional operation. It requires an output end for the signal and an input end used for supplying the predetermined information signal to the microprocessor.

If the microprocessor is connected to more than one load device (which is the normal usage), then a large number of terminals are required. This is a drawback. This is because the microprocessor is small in size because it is made up of chips, and it requires a large number of connecting lines, so that it occupies a large space.

It is also possible to provide the microprocessor with one so-called single bidirectional input instead of separate input and output sides, however, due to the internal resistance with the bidirectional input of the load device Limited to small cases. In the case of high-power load devices, therefore, in the past, separate input and output sides have been provided in the microprocessor for actuation and display of the load device, which would lead to the disadvantages mentioned above.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention An object of the present invention is to provide a circuit device which operates a load device by the microprocessor and can display the operating state of the microprocessor in which the space is small and the microprocessor can be used with a small number of terminals. To provide.

Means for Solving Problems The above problem is solved by the configuration described in the characterizing portion of the first aspect of the invention in the circuit device according to the higher concept of the first aspect of the invention.

With the above configuration, both the operation of the load and the display of the operation state at each time can be performed through only one terminal of the microprocessor, that is, only one lead wire to the microprocessor is required. I'm done. Through this lead the terminal of the microprocessor can be used both as input and output side and depending on whether the manual switch is activated or not the load device can be driven by a digital signal ("1" or It can be controlled by "0"). The advantage of this configuration is that a load device with a large load can be controlled via the circuit arrangement of the invention.

By operating and displaying the load device via only one input / output side of the microprocessor, the size of the terminals of the microprocessor can be reduced, the number of terminals can be reduced, and the number of required terminal lead wires can be reduced. This in turn saves space.

In one embodiment of the invention, the microprocessor issues a plurality of pulses to interrogate (multiple interrogation),
Detects whether the manual switch is activated or not.
This multiplex query causes the microprocessor to detect that the manual switch has been actuated, i.e. in this case the terminals of the microprocessor act as inputs. The microprocessor subsequently controls the load device by means of a digital signal, that is to say the lead and thus the terminal act in this case as the output.

In this way, since only one lead wire is required, it is preferable to use the circuit device of the present invention in an automobile. That is, the above-mentioned manual switch is, for example, a traveling beam switch or an operation lever of an automatic transmission. The actuation of such a manual switch is transmitted to the microprocessor which in turn turns on the control lamp or indicator lamp to provide the desired sequence control.

 Further embodiments of the invention are described in the embodiments section.

Examples Next, the present invention will be described in detail based on examples with reference to the drawings.

In the circuit arrangement shown in FIG. 1, the load 10 configured for display as a light emitting diode is a resistor 12
And the manual switch 14 and is connected to the operating voltage + U _B.

The other side of the resistor, one side of which is connected to the load 10, is connected via the terminal 16 to an electronic switch 18 shown in phantom and a digital circuit 24 also shown in phantom. It is connected. The electronic switch 18 and the digital circuit 24 are connected to a common electronic terminal 20 of the schematically shown microprocessor 22.

The electronic switch 18 includes a first transistor 26 and a terminal 16
And a collector resistor 28 connected to the base, a resistor 30 connected to the base, and an amplifier stage 32 connected on the output side to the resistor 30 and on the input side to the electrical terminal 20 of the microcomputer 22. ing.

The digital circuit 24 has a resistor 34 connected to terminal 16.
And the threshold circuit 40 connected to the resistor 34,
It has a diode 38 and a capacitor 36 which are connected to the diode 38.
Is connected to earth voltage. Further digital circuit 24
Is provided with a diode 42 connected to the output side of the threshold circuit 40 in the blocking direction, and the diode 42 is connected to the electric terminal 20 of the microprocessor 22.

The voltage U ₁ applied to the electronic switch 18 and the digital circuit 24 depends on the operating state of the first transistor 26 +
The dimensions of the circuit elements are determined to have a value greater than U _B or 3V. In any case, this voltage U ₁ is of sufficient magnitude to control the threshold circuit 40 or the all-digital circuit 24 so that the output of the threshold circuit 40 is supplied with a digital signal “1”. ing.

The signal "1" taken from the output side of the threshold circuit 40 is blocked by the diode 42, and the microprocessor 22 is connected to the terminal.
The signal “1” or the signal “0” can be supplied via the amplification stage 32 via 20. Therefore, the load 10 can be controlled via the first transistor 26.

When the manual switch 14 is activated, the digital circuit device 24
Since the signal "0" is taken out from the output side of, ie, the output side of the threshold circuit 40, the input side voltage U _E supplied to the terminal 20 of the microprocessor 22 also becomes the state of the signal "0".

The aforementioned condition is illustrated by the lower curve 78 in FIG. Microprocessor 22 sends a pulse 72 to interrogate three times to detect actuation of manual switch 14. This interrogation is performed by detecting that the input voltage U _E is in the state of the signal "0" using the pulse 72. Upon detecting this condition by three sequential pulses 72, the microprocessor 22 detects the actuation of the manual switch 14. The pulse width of pulse 72 is about 20
μs and the pulse interval is 20 ms.

After activation of the manual switch 14, the microprocessor 22 can reconnect or disconnect the load 10. In this way, the electrical terminal 20 of the microprocessor 22 can be used both as input and output, ie the actuation and indication of the load 10 is via only one terminal with only one lead wire. Can be done by The premise for this circuit device to perform the desired functional operation is the transistor
The signal "1" is taken out from the output side of the threshold circuit 40 regardless of whether 26 is blocked or conducting.

Therefore, in order to be able to extract the signal "1" from the output of the threshold circuit 40 in any case, the voltage U ₁ must be greater than the threshold voltage of the threshold circuit 40. This signal "1" is suppressed when the manual switch 14 is actuated, which the microprocessor 22 detects by the multiplex interrogation. That is, the terminal 20 of the microprocessor operates in both directions and is thus used both as the input side and the output side.

Another embodiment of the circuit arrangement according to the invention is shown in FIG. In this embodiment, instead of the threshold circuit 40, a switching stage 44 and a switching transistor 52 connected downstream thereof are used, which switching transistor 52 is connected to the output side of the switching stage 44 via a resistor 50. There is. A capacitor 48 is connected to the input side of the switching stage 44 for amplification, and this capacitor 48 is connected to the ground potential. The switching stage is connected to the terminal 16 via the resistor 46.

The collector of the switching transistor 52 is connected to the terminal 20 of the microprocessor 22, which in turn is connected to an amplifier 56 and to a transistor 54 which is connected via a resistor to this amplifier 56.

In the circuit arrangement shown in FIGS. 1 and 3, the operating voltage + U _B is 12V and the input voltage U _{1 has} a value greater than 3V. It is shown in FIG. In another embodiment of the present invention, the input voltage U ₁ can be reduced to several hundred millivolts, that is, a minute voltage change can be detected. This can be done by connecting the output side of the comparator 58 to the terminal 20 of the microprocessor 22.

The input side of the comparator 58 is connected to the voltage divider 74, 76 connected to the voltage + U and the ground potential, and the other input side of the comparator is connected to the terminal 16 via the resistor 80. 16 is connected to ground potential via another resistor 82.

Further, the terminal 16 is connected to the second transistor 60 via the diode 64, and the second transistor 60 is also connected.
The base of is connected to the amplifier 62 via a resistor. The input side of the amplifier 62 is connected to the common terminal 20 of the microprocessor.
Connected with.

In the same way that the voltage U ₁ could be made small in the embodiment of FIG. 4, it is shown in FIGS. 5 to 7 instead of the second transistor 60 shown in FIG. The voltage U ₁ can be reduced by using a transistor.

In FIG. 5, the PTC resistor 66 is connected to the collector of the transistor 26. An open collector third transistor 68 is used in FIG.
In the figure an open drain actuated FET (field effect transistor) is used.

In the above and all embodiments, the input and output signals are controlled by the microprocessor and the microprocessor is able to ask questions. In these cases, there is an advantage that the reset signal is not required. Since the operation of the manual switch 14 is detected by the microprocessor 22, no erroneous detection due to individual fault pulses will occur.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a circuit device according to a first embodiment of the present invention. FIG. 2 is a waveform diagram for explaining a question by the microprocessor. 3 to 7 are circuit diagrams showing another embodiment of the circuit device or a part of the circuit device of the present invention. 10 ... Load, 14 ... Manual switch, 18 ... Electronic switch, 22 ... Microprocessor, 24 ... Digital circuit, 40 ... Threshold circuit, 72 ... Pulse interval, 44 ... Switching stage, 58 ... … Comparator, 66 …… PTC resistor,

Claims (10)

[Claims] 1. The load can be additionally switched by a manually operable manual switch, the microprocessor being used to operate the load by an electronic switch controllable from an electrical terminal of the microprocessor. In the circuit device for displaying the operating state, the electric terminal (20) of the microprocessor (22) for controlling the electronic switch (18) is simultaneously connected to the output side of the digital circuit device (24), (24) is controlled by a manual switch (14), and when the manual switch (14) is operated, the output side of the digital circuit device (24) and the electric terminal () of the microprocessor (22) ( 20) is forcibly placed at "0" potential (earth potential), and the corresponding operation is not performed, the microprocessor (22) electrical The terminal (20) is not controlled by the digital circuit device (24), and the manual switch (14) is operated by a microprocessor using a plurality of pulses (72) at the electric terminal (20) of the microprocessor (22). (22) A circuit device for operating a load using a microprocessor characterized by being identified by multiple queries. 2. A digital circuit device (24) is constituted by a threshold circuit (40) and a diode (42) which is connected in the shut-off direction afterward, and the anode of the diode (42) is a microprocessor. A circuit device for operating a load using the microprocessor according to claim 1, which is connected to an electric terminal (20) of (22). 3. A digital circuit device (24) is constituted by a switching stage (44) for performing amplification and a switching transistor (52) which is connected afterwards, and the collector of the switching transistor (52) is a micro. A circuit arrangement for operating a load using a microprocessor according to claim 1 in connection with an electrical terminal (20) of a processor (22). 4. A digital circuit (24) comprises a comparator (58) and an open collector transistor (60), and the output side of the comparator (58) is an electric terminal (20) of a microprocessor (22). A circuit arrangement for operating a load using the microprocessor according to claim 1 connected to the circuit. 5. The electric switch (18) comprises an amplification stage (32) and the amplification stage (32) is controlled by a microprocessor (22) via an electrical terminal (20). A circuit device for operating a load using the microprocessor according to any one of claims 1 to 4. 6. An electronic switch (18) comprising a first transistor (26) and said first transistor (2).
6) The collector of the manual switch (1) via the resistor (28)
A circuit arrangement for operating a load using a microprocessor according to claim 5 connected to 4) and a load (10). 7. The electronic switch (18) comprises a second transistor (60), and the second transistor (6).
Circuit arrangement for operating a load with a microprocessor according to claim 4, in which the collector of (0) is connected to a diode (64). 8. Circuit arrangement for operating a load with a microprocessor according to claim 6, wherein the resistor is a PTC resistor (66). 9. An electronic switch comprising a third transistor (68) having an open collector.
A circuit device for operating a load using the microprocessor according to the paragraph. 10. A circuit arrangement for operating a load using a microprocessor according to claim 5, wherein the electronic switch is constituted by an open drain actuated field effect transistor (FET).