JP3016057U - Signal input circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] By efficiently using the input port of the microprocessor unit, it is possible to easily deal with the increase in functions.
A signal input circuit that can suppress an increase in cost is also provided. A plurality of operation input switches are provided, a voltage signal corresponding to an operated operation input switch is generated, and the generated voltage signal is supplied to an input port terminal of a microprocessor unit having an A / D conversion circuit. An operation switch signal input analog circuit and a dew condensation detection circuit that supplies the external environment detection digital signal output from the external environment sensor to the input port terminal with priority over the voltage signal.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a signal input circuit, and more particularly to a signal input circuit that can efficiently use an input port of a microprocessor unit.

[0002]

[Prior art]

 FIG. 2 is a circuit diagram showing the configuration of a signal input circuit in a conventional video tape recorder device. In the figure, 51 is a microprocessor unit having a built-in A / D conversion circuit, A1 is a first input port terminal, A2 is a second input port terminal, and P0, P1 and P2 are other input port terminals.

Reference numeral 52 is a first operation switch signal input circuit, in which a resistor R1, a resistor R2, a resistor R3, a resistor R4, and a resistor R5 are connected in series, and one end of the resistor R1 is connected to a plus side power source + B. It is connected. The connection point between the resistors R1 and R2 is connected to the first input port terminal A1 of the microprocessor unit 51. The operation input switch POW is a switch for instructing ON / OFF of power supply to the video tape recorder device, and is connected between the connection point of the resistors R1 and R2 and the ground.

The operation input switch PLY is a switch for instructing a reproducing operation, and is connected between the connection point of the resistors R2 and R3 and the ground. The operation input switch FFS is a switch for instructing a fast-forward operation, and is connected between the connection point of the resistors R3 and R4 and the ground. The operation input switch REW is a switch for instructing a rewinding operation, and is connected between the connection point of the resistors R4 and R5 and the ground. The operation input switch REC is a switch for instructing a recording operation, and is connected between one end of the resistor R5 and the ground.

On the other hand, reference numeral 53 is a second operation switch signal input circuit, in which a resistor R6, a resistor R7, a resistor R8, a resistor R9, and a resistor R10 are connected in series, and one end of the resistor R6 is a plus power source + B. It is connected to the. The connection point of the resistors R6 and R7 is connected to the second input port terminal A2 of the microprocessor unit 51. The operation input switch STO is a switch for instructing stop, and is connected between the connection point of the resistors R6 and R7 and the ground. The operation input switch PAU is a switch for performing a pause operation, and is connected between the connection point of the resistor R7 and the resistor R8 and the ground.

The operation input switch TVC is a switch for instructing switching between the television channel and the video channel, and is connected between the connection point of the resistors R8 and R9 and the ground. The operation input switch CHU is a switch for instructing a switching operation for switching the television channel in the direction of the larger channel number, and is connected between the connection point of the resistors R9 and R10 and the ground. The operation input switch CHD is a switch for instructing a switching operation for switching the TV channel in the direction of the smaller channel number, and is connected between one end of the resistor R10 and the ground.

A dew condensation sensor circuit 54 includes a bias circuit 54a, a dew condensation sensor DEW, and a transistor switch Q1. The collector terminal of the transistor switch Q1 is connected to the input port terminal PO of the microprocessor unit 51.

An unillustrated power failure detection circuit is connected to the input port terminal P1 of the microprocessor unit 51, and an unillustrated power supply abnormality detection circuit is connected to the input port terminal P2.

Next, the operation will be described. In the signal input circuit of the video tape recorder device, when any one of the operation input switches POW, PLY, FFS, REW, and REC of the first operation switch signal input circuit 52 is closed, the operation input switch which is closed is closed. By this, a voltage dividing circuit of the power supply voltage by the resistance is formed between the positive side power supply + B and the ground, and a voltage signal corresponding to the closed operation input switch is generated at the connection point of the resistance R1 and the resistance R2. The voltage signal is supplied to the first input port terminal A1.

When any one of the operation input switches STO, PAU, TVC, CHC, and CHD of the second operation switch signal input circuit 53 is closed, the positive operation power switch causes a plus side power source + B. A voltage divider circuit is formed between the ground and the resistor, and a voltage signal corresponding to the closed operation input switch is generated at the connection point between the resistors R6 and R7, and this voltage signal is supplied to the second input port terminal A2. To be done.

The A / D conversion circuit of the microprocessor unit 51 converts the voltage signal supplied to the first input port terminal A1 and the second input port terminal A2 into digital data. The microprocessor unit 51 identifies the closed operation input switch based on the digital data, and controls the video tape recorder device according to the closed operation input switch.

Further, in the dew condensation sensor circuit 54, the resistance value of the dew condensation sensor DEW changes according to the dew condensation state, and when the resistance value of the dew condensation sensor DEW reaches a predetermined value, the transistor Q 1 is turned on to detect the dew condensation. The signal is supplied to the terminal PO of the input port of the microprocessor unit 51. When the dew condensation detection signal is supplied to the input port terminal PO, the power failure detection signal is supplied to the input port terminal P1, and the power supply abnormality detection signal is supplied to the input port terminal P2, the microprocessor unit 51 receives , Executing a predetermined program and controlling the video tape recorder device to stop the operation by prioritizing the voltage signal output from the first operation switch signal input circuit 52 and the second operation switch signal input circuit 53. And so on.

[0013]

[Problems to be solved by the device]

 In the signal input circuit of the conventional video tape recorder device, the voltage signal corresponding to the operation input switch is configured to be supplied to the first input port terminal A 1 and the second input port terminal A 2 of the microprocessor unit 51. The dew condensation detection signal, the power failure detection signal, and the power supply abnormality detection signal are supplied to the input port terminals P0, P1, and P2, respectively.

That is, in addition to the first input port terminal A1 and the second input port terminal A2, the input port terminals P0, P1, P2 are required as signal input terminals, and the input port terminal of the microprocessor unit is Since it is assigned for inputting the dew condensation detection signal, power failure detection signal, and power supply abnormality detection signal, the input terminals for other signals are limited accordingly, and the increase in the functions of the video tape recorder device is reduced accordingly. In order to increase the functions of the video tape recorder device, there was a problem that it was necessary to replace the I / O port itself or change the setting of the input port by the program.

The present invention has been made to solve the above-described problems, and can efficiently use the input port of the microprocessor unit, easily cope with the increase in functions, and It is an object of the present invention to provide a signal input circuit that can suppress an increase in cost due to an increase in functions.

[0016]

[Means for Solving the Problems]

 A signal input circuit according to the present invention has a plurality of operation input switches, and when the operation input switch is operated, a voltage signal corresponding to the operation input switch is generated, and the generated voltage signal is A / D. The operation switch signal input analog circuit that supplies to the input port terminal of the microprocessor unit equipped with the conversion circuit, and the external environment detection digital signal takes precedence over the above voltage signal when the external environment sensor detects a predetermined condition of the external environment. And an external environment detection digital circuit for supplying to the input port terminal.

Further, one end of the voltage dividing circuit in which a plurality of resistors are connected in series is connected to the positive power source, and the voltage dividing point and the graph except the first voltage dividing point closest to the positive power source side of the voltage dividing circuit. The operation switch signal input analog circuit, which is connected with the operation input switch, and the external environment sensor, which is connected to the first voltage dividing point and monitors the external environment, detects a predetermined condition of the external environment. An external environment detection digital circuit that sometimes short-circuits the first voltage dividing point and the ground is provided, and the first voltage dividing point is connected to an input port terminal of the microprocessor unit.

Further, in the signal input circuit configured as described above, the external environment sensor is a dew condensation sensor or a power failure or abnormality detection sensor of the power supply. In addition, in the signal input circuit thus configured, a plurality of external environment detection digital circuits are connected to the first voltage dividing point via the OR circuit.

Further, in the signal input circuit configured as described above, as the external environment detection digital circuit, the first external environment detection digital circuit provided with the power failure detection sensor and the second external environment provided with the abnormality detection sensor are provided. There is a detection digital circuit, and these first and second external environment detection digital circuits are connected to the first voltage dividing point via the OR circuit.

[0020]

[Action]

 The signal input circuit according to the present invention, when an external environment sensor such as a dew condensation sensor, a power failure or an abnormality detection sensor detects a predetermined condition of the external environment, for example, dew condensation, a power failure of the power source or an abnormality of the power source, By supplying the external environment detection digital signal to the input port terminal to which the operation switch signal input analog circuit is connected, and by giving priority to the external environment detection digital signal over the analog voltage signal output from the operation switch signal input circuit. , The other input port terminals of the microprocessor unit can be assigned to other signals, and the input ports of the microprocessor unit can be used efficiently, so that it is possible to easily cope with the increase of the functions and further increase the functions. The increase in cost can be suppressed.

Further, one end of the voltage dividing circuit in which a plurality of resistors are connected in series is connected to the positive power source, and the voltage dividing point and the graph except the first voltage dividing point closest to the positive power source side of the voltage dividing circuit. Operation switch signal input analog circuit that is connected to each other with operation input switches and an external environment that is connected to the first voltage dividing point and monitors external environment such as dew condensation, power failure or power failure. An external environment detection digital circuit that short-circuits the first voltage dividing point and the ground when the environment sensor detects a predetermined condition of the external environment, and the first voltage dividing point is the input port terminal of the microprocessor unit. Since it is possible to assign the other input port terminal of the microprocessor unit to another signal by connecting to, the input port of the microprocessor unit can be used efficiently, It is possible to easily cope with the increase in functions, and further suppress the increase in cost due to the increase in functions.

Furthermore, when a plurality of external environment sensors that monitor the external environment detect a predetermined state of the external environment, an external part that short-circuits the first voltage dividing point and the ground via the OR circuit. By including the environment detection digital circuit and connecting the first voltage dividing point to the input port terminal of the microprocessor unit, the number of input ports of the microprocessor unit is further reduced, and the microprocessor unit Since the input port can be used efficiently, it is possible to easily cope with the increase in the function and further suppress the increase in the cost due to the increase in the function.

[0023]

【Example】

 An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, parts that are the same as or correspond to those in FIG. 2 are given the same reference numerals and explanations thereof are omitted. Here, reference numeral 11 is a first operation switch signal input analog circuit, and resistors R101, R111, R102, R103, R104, and R105 are connected in series to form a voltage dividing circuit, and one end of the resistor R101 has a plus side power source + B. Voltage dividing points d1 to d6 are formed at the connection point of these resistors and the tip of the resistor R105 on the side opposite to the positive side power source + B side.

The voltage dividing point (first voltage dividing point) d1 closest to the plus side power source + B side is connected to the first input port terminal A1 of the microprocessor unit 51. The operation input switches POW, PLY, FFS, REW and REC are connected between the voltage dividing points d2, d3, d4, d5 and d6 and the ground, respectively. Further, 55 is a dew condensation sensor circuit which is one of the external environment detection digital circuits, and Q1 is a transistor switch. The collector terminal of Q1 is connected to the first voltage dividing point d1, and when the dew condensation sensor DEW detects dew condensation, the first voltage dividing point d1 and the ground are short-circuited.

On the other hand, 12 is a second operation switch signal input analog circuit, and resistors R106, R112, R107, R108, R109, and R110 are connected in series to form a voltage dividing circuit, and one end of the resistor R106. Is connected to the plus side power source + B, and voltage dividing points d7 to d12 are formed at the connection point of these resistors and the tip of the resistor R110 on the side opposite to the plus side power source + B side.

The voltage dividing point (first voltage dividing point) d7 closest to the plus side power source + B side is connected to the second input port terminal A2 of the microprocessor unit 51. The operation input switches STO, PAU, TVC, CHU, CHD are respectively connected between the voltage dividing points d8, d9, d10, d11, d12 and the ground. The output terminal of the OR circuit 1 is also connected to the first voltage dividing point d7.

The input terminal of the OR circuit 1 is connected to the power supply monitoring signal supply circuit 2 which is another external environment detection digital circuit. The power supply monitoring signal supply circuit 2 detects the occurrence of a power failure and outputs an "L" level power failure occurrence detection signal, that is, a power failure occurrence detection circuit that short-circuits the first voltage dividing point d7 and the ground (power failure detection Sensor) and a power supply abnormality detection circuit that detects a power supply abnormality and outputs an “L” level power supply abnormality detection signal, that is, a power supply abnormality detection circuit (abnormality detection sensor) that short-circuits the first voltage dividing point d7 and the ground. ing.

Next, the operation will be described. In the first operation switch signal input circuit 11, when any of the operation input switches POW, PLY, FFS, REW, and REC is closed, the closed operation input switch causes connection between the plus side power source + B and the ground. The voltage is divided according to the resistance value ratio, and the divided voltage signal at the first voltage dividing point d1 is supplied to the first input port terminal A1.

In the dew condensation sensor circuit 55, the resistance value of the dew condensation sensor DEW changes in accordance with the dew condensation state, and when the resistance value of the dew condensation sensor DEW reaches a predetermined value, the transistor Q 1 is turned on and “L” is set. A "level dew condensation detection signal is supplied to the first input port terminal A1.

Therefore, when the condensation detection circuit 55 outputs the condensation detection signal while the voltage signal is being output from the first operation switch signal input circuit 11, the first input port terminal A1 and the ground are short-circuited. Then, the potential becomes “L” level, and the dew condensation detection signal is given priority and supplied to the microprocessor unit 51.

The A / D conversion circuit of the microprocessor unit 51 converts the signal supplied to the first input port terminal A1 into digital data. The microprocessor unit 51 identifies the closed operation input switch or the dew condensation state based on the digital data, and executes a predetermined program to perform control.

On the other hand, in the second operation switch signal input circuit 12, when any of the operation input switches STO, PAU, TVC, CHU, CHD is closed, the closed operation input switch causes the plus side power source + B and ground. The voltage between and is divided according to the resistance value ratio, and the divided voltage signal at the first voltage dividing point d7 is supplied to the second input port terminal A2.

At this time, if the power failure occurrence detection circuit of the power supply monitoring circuit 2 detects a power failure or the power supply abnormality detection circuit detects a power supply abnormality, the second input port terminal A2 and the ground are OR circuits. 1 is short-circuited and the power failure detection signal or the power supply abnormality detection signal is supplied to the second input port terminal A2.

Since the output of the OR circuit 1 is a digital signal of “L” level, a power failure detection signal or a power supply abnormality detection signal is output while the voltage signal is being output from the second operation switch signal input circuit 12. Is supplied to the second input port terminal A2 via the OR circuit 1, the potential of the second input port terminal A2 becomes “L” level, and the power failure detection signal or the power supply abnormality detection signal is given priority. It is supplied to the unit 51.

The A / D conversion circuit of the microprocessor unit 51 converts the signal supplied to the second input port terminal A2 into digital data. Based on the digital data, the microprocessor unit 51 identifies the closed operation input switch or the state of power failure or power failure, and executes a predetermined program to perform control.

[0036]

[Effect of device]

 As described above, according to the present invention, the output signal of the external environment detection digital circuit (condensation detection signal, power failure detection signal, power supply abnormality detection signal, etc.) and the analog voltage signal of the operation switch signal input circuit are the same input port. Since the output signal of the external environment detection digital circuit is prioritized over the analog voltage signal output from the operation switch signal input circuit, the other input port terminals of the microprocessor unit should be assigned to other signals. The input port of the microprocessor unit can be used efficiently. As a result, it is possible to avoid the situation where the number of input port pins is insufficient when increasing the number of functions, and it is not necessary to change the input port by hardware or software to increase the number of input port pins, increasing the number of functions. It is possible to suppress an increase in cost associated with. In addition, the number of input port pins can be reduced, making it easier to mount on the board.

Further, one end of the voltage dividing circuit in which a plurality of resistors are connected in series is connected to the positive power source, and the voltage dividing point and the ground except for the first voltage dividing point closest to the positive power source side of the voltage dividing circuit. And the operation switch signal input analog circuit connected to each other with the operation input switch and the external environment sensor connected to the first voltage dividing point and monitoring the external environment detects the predetermined condition of the external environment. Since an external environment detection digital circuit that short-circuits the 1st voltage dividing point and the ground is provided so that the 1st voltage dividing point is connected to the input port terminal of the microprocessor unit, the input port of the microprocessor unit is connected. Can be used efficiently. As a result, it is possible to avoid the situation where the number of input port terminals is insufficient when increasing the number of functions, and it is not necessary to change the input port by hardware or software to increase the number of input port terminals. It is possible to suppress an increase in cost associated with an increase in functions. In addition, the number of input port pins can be reduced, making it easier to mount on the board. If a plurality of external environment detection digital circuits are connected to the first voltage dividing point via the OR circuit, more input signals can be sent to the input port terminals of a single microprocessor unit. Therefore, the input port of the microprocessor unit can be used more efficiently.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a signal input circuit according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a signal input circuit in a conventional video tape recorder device.

[Explanation of symbols]

1 OR circuit 2 Power supply monitoring signal supply circuit (external environment detection digital circuit) POW operation input switch PLY operation input switch FFS operation input switch REW operation input switch REC operation input switch STO operation input switch PAU operation input switch TVC operation input switch CHU operation Input switch CHD Operation input switch 11 First operation switch signal input analog circuit 12 Second operation switch signal input analog circuit A1 First input port terminal A2 Second input port terminal 51 Microprocessor unit DEW Condensation sensor (external environment sensor) 55 Condensation sensor circuit (external environment detection digital circuit) d1 1st voltage dividing point d7 1st voltage dividing point

Claims (6)

[Scope of utility model registration request] 1. A micro controller having a plurality of operation input switches, the operation input switches being operated to generate a voltage signal corresponding to the operation input switches, and the generated voltage signal having an A / D conversion circuit. The operation switch signal input analog circuit supplied to the input port terminal of the processor unit, and the external environment detection digital signal to the input port terminal in priority to the voltage signal when the external environment sensor detects a predetermined condition of the external environment. A signal input circuit comprising: an external environment detection digital circuit for supplying. 2. A voltage dividing circuit, in which a plurality of resistors are connected in series, is connected at one end thereof to a positive power source, and the voltage dividing point and ground except for the first voltage dividing point closest to the positive power source side of the voltage dividing circuit. And an operation switch signal input analog circuit connected to each other by operation input switches, and an external environment sensor connected to the first voltage dividing point for monitoring the external environment detects a predetermined condition of the external environment. A signal input circuit, comprising: an external environment detection digital circuit for short-circuiting a first voltage dividing point and a ground, wherein the first voltage dividing point is connected to an input port terminal of a microprocessor unit. 3. The signal input circuit according to claim 1, wherein the external environment sensor is a dew condensation sensor. 4. The signal input circuit according to claim 1, wherein the external environment sensor is a power failure or abnormality detection sensor of a power source. 5. The signal input circuit according to claim 2, wherein there are a plurality of external environment detection digital circuits, and the plurality of external environment detection digital circuits are connected to the first voltage dividing point via an OR circuit. 6. The external environment detection digital circuit includes a first external environment detection digital circuit including a power failure detection sensor and a second external environment detection digital circuit including a power supply abnormality detection sensor. The signal input circuit according to claim 2, wherein the first and second external environment detection digital circuits are connected to the first voltage dividing point via an OR circuit.