Microcontroller IO circuit for expanding input interface

Abstract

The utility model relates to the technical field of control circuits, and discloses a microcontroller IO circuit for expanding an input interface, which comprises a 74HC245 chip interface circuit, a power supply circuit and an input data display circuit, the 74HC245 chip interface circuit is composed of a 74HC245 chip circuit and a microcontroller circuit, and the 74HC245 chip circuit is connected to a corresponding pin of a microcontroller; the power supply circuit is composed of a 24V to 5V circuit and a 5V to 3.3 V circuit, and a 24V external power supply is converted into a 3.3 V voltage used by the 74HC245 chip interface circuit through the power supply circuit; the input data display circuit accesses an external input signal to the 74HC245 chip interface circuit, and the light emitting diode is lightened through the external input signal. According to the utility model, the 74HC245 chip interface circuit is externally connected with the power supply circuit and the input data display circuit, so that the problem that the number of input pins of the microcontroller is insufficient is solved, the development requirements can be met, the development cost is reduced, and the working efficiency can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to control circuit technical field, concretely is a kind of microcontroller IO circuit of extension input interface. BACKGROUND

[0002] In the development process of product, according to the requirement of development function, more input IO port is used, and the number of input and output port of each model microcontroller is mostly fixed, therefore, microcontroller needs to be matched with other chips to expand multi-channel IO input circuit to meet the demand. SUMMARY

[0003] To solve the technical problems in the background art, the utility model provides a kind of microcontroller IO circuit of extension input interface.

[0004] The utility model provides a kind of microcontroller IO circuit of extension input interface, including 74HC245 chip interface circuit, power supply circuit and input data display circuit;

[0005] 74HC245 chip interface circuit is composed of 74HC245 chip circuit and microcontroller circuit, and 74HC245 chip circuit is connected to the corresponding pin of microcontroller;

[0006] Power supply circuit is composed of 24V-5V circuit and 5V-3.3V circuit, and the voltage of 3.3V used by 74HC245 chip interface circuit is converted from the external power supply of 24V by power supply circuit;

[0007] Input data display circuit connects external input signal to 74HC245 chip interface circuit, and light-emitting diode is lighted by external input signal.

[0008] As the further optimization scheme of the utility model, 74HC245 chip of 74HC245 chip circuit has 20 pins, and 16 pins are used for data transmission, and the remaining 4 pins are used for power supply and ground connection.

[0009] As the further optimization scheme of the utility model, the 19th pin of 74HC245 chip is CS pin, the 1st pin is DIR pin, the 2nd to 9th pin is data A transmission pin, and the 11th to 18th pin is data B transmission pin.

[0010] When CS pin and DIR pin are low level, data is transmitted from B to A;

[0011] When CS pin and DIR pin are high level, data is transmitted from A to B;

[0012] When CS pin is high level, DIR level is not considered as isolation state.

[0013] As a further optimization scheme of the utility model, 24V turns 5V circuit includes TPS5450DDAR chip circuit, through TPS5450DDAR chip circuit will external input voltage 24V be converted into 5V, provide input voltage for 5V turns 3.3V circuit.

[0014] As a further optimization scheme of the utility model, 5V turns 3.3V circuit includes 1117 chip circuit, and 24V turns 5V circuit output 5V voltage is converted into 3.3V by 1117 chip circuit, provides voltage for 74HC245 chip interface circuit.

[0015] As a further optimization scheme of the utility model, input data display circuit includes TPL291-4 chip circuit, and TPL291-4 chip has input signal pin RTK+, RTK-, IN2, IN3, IN4, IN5, IN6, IN7, IN8, and input signal pin IN2, IN3, IN4, IN5, IN6, IN7, IN8 are connected with the corresponding pin IN-1, IN-2, IN-3, IN-4, IN-5, IN-6, IN-7, IN-8 of 74HC245 chip respectively;

[0016] When the input signal is low level, the light-emitting diode in TPL291-4 chip circuit is in the state of lighting, when the input signal is high level, the light-emitting diode in TPL291-4 chip circuit is in the state of not lighting.

[0017] The microcontroller IO circuit of the extended input interface has the following beneficial effects:

[0018] The utility model discloses through 74HC245 chip interface circuit external power supply circuit and input data display circuit, solved the microcontroller self-possessed input pin number shortage problem, can satisfy the development demand, reduces the development cost's simultaneously, still can improve work efficiency.

[0019] The additional aspects and advantages of the utility model will be partly given in the following description, and some will become obvious from the following description, or be understood by the practice of the utility model. ACCURACY OF DRAWINGS

[0020] Figure 1 It is 74HC245 chip circuit diagram of the utility model;

[0021] Figure 2 It is microcontroller circuit diagram of the utility model;

[0022] Figure 3 It is 24V turns 5V circuit diagram of the utility model;

[0023] Figure 4 5V to 3.3V circuit diagram of the utility model;

[0024] Figure 5 Input data display circuit diagram of the utility model. DETAILED DESCRIPTION

[0025] Embodiments of the utility model are described in detail below, examples of the embodiments are represented in the drawings, wherein the same or similar symbols represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, only for explaining the utility model, and cannot be understood as limiting the utility model.

[0026] It needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model.

[0027] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the utility model, the meaning of "multiple" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0028] In the utility model, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection or communication with each other; it can be directly connected, or indirectly connected through intermediate medium, it can be the communication or interaction relationship between two elements, unless otherwise specifically limited. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0029] In the utility model, unless another definite provision and limitation, first feature is on second feature "on" or "under", first and second features can be direct contact, or first and second features are indirectly contacted through intermediate medium.Moreover, first feature "on", "above" and "on" second feature can be first feature is directly above or obliquely above second feature, or only indicates that the horizontal height of first feature is higher than second feature.

[0030] As Figures 1-5 shown, a microcontroller IO circuit of extended input interface includes 74HC245 chip interface circuit, power supply circuit and input data display circuit.

[0031] The 74HC245 chip interface circuit is composed of 74HC245 chip circuit and microcontroller circuit, and the 74HC245 chip circuit is connected to the corresponding pin of the microcontroller.

[0032] The 74HC245 chip interface circuit is a bidirectional buffer, which can realize data transmission between two buses, one of which is input and the other is output, while the 74HC245 buffers and adjusts data between the two buses, and its main function is to ensure the transmission quality of signals between different buses, avoiding signal distortion or loss.

[0033] The power supply circuit is composed of 24V to 5V circuit and 5V to 3.3V circuit, and the 24V external power supply is converted to 3.3V voltage for the 74HC245 chip interface circuit through the power supply circuit.

[0034] The input data display circuit connects the external input signal to the 74HC245 chip interface circuit, and the light-emitting diode is lit through the external input signal.

[0035] Specifically, as Figure 1 and Figure 2 shown, the 74HC245 chip of the 74HC245 chip circuit has 20 pins, of which 16 are data transmission pins, and the remaining 4 are used for power and ground connection.

[0036] Further, the 19th pin of the 74HC245 chip is the CS pin, the 1st pin is the DIR pin, the 2nd to 9th pins are the data A transmission pins, and the 11th to 18th pins are the data B transmission pins.

[0037] When the CS pin and the DIR pin are both low, the data is transmitted from B to A.

[0038] When the CS pin and the DIR pin are high, data is transmitted from A to B;

[0039] When the CS pin is high, the DIR level is isolated regardless of the level.

[0040] Specifically, as shown in the figure, Figure 3 The 24V-to-5V circuit includes a TPS5450DDAR chip circuit, which converts the external input voltage 24V to 5V to provide an input voltage for the 5V-to-3.3V circuit.

[0041] As shown in the figure, Figure 4 The 5V-to-3.3V circuit includes a 1117 chip circuit, which converts the 5V voltage output by the 24V-to-5V circuit to 3.3V to provide a voltage for the 74HC245 chip interface circuit, the 20th pin of the 74HC245 chip provides a voltage that can switch the CE pin of the 74HC245 chip to input data and stably power the microcontroller.

[0042] Specifically, as shown in the figure, Figure 5 The input data display circuit includes a TPL291-4 chip circuit, which has input signal pins RTK+, RTK-, IN2, IN3, IN4, IN5, IN6, IN7, and IN8, and the input signal pins IN2, IN3, IN4, IN5, IN6, IN7, and IN8 are connected to the corresponding pins IN-1, IN-2, IN-3, IN-4, IN-5, IN-6, IN-7, and IN-8 of the 74HC245 chip, respectively.

[0043] When the input signal is low, the light-emitting diode in the TPL291-4 chip circuit is in the lit state, and when the input signal is high, the light-emitting diode in the TPL291-4 chip circuit is in the unlit state.

[0044] The TPL291-4 chip circuit has multiple pull-up resistors and light-emitting diodes, where R23, R29, R37, R45, R55, R61, R69, and R77 are pull-up resistors for each input data, and D8, D11, D14, D18, D24, D27, D30, and D34 are light-emitting diodes for each input data, which are provided with a 3.3V pull-up resistor voltage.

[0045] In summary, the 74HC245 chip interface circuit is externally connected to a power supply circuit and an input data display circuit, which solves the problem of insufficient number of input pins of the microcontroller, meets the development needs, reduces the development cost, and improves the work efficiency.

[0046] The above merely describes a preferred embodiment of the present application, and the protection scope of the present application is not limited thereto, and any skilled person in the art, according to the technical scheme and the inventive concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A microcontroller I / O circuit for expanding input interfaces, characterized in that, This includes the 74HC245 chip interface circuit, power supply circuit, and input data display circuit; The 74HC245 chip interface circuit consists of a 74HC245 chip circuit and a microcontroller circuit. The 74HC245 chip circuit is connected to the corresponding pins of the microcontroller. The power supply circuit consists of a 24V to 5V circuit and a 5V to 3.3V circuit. The power supply circuit converts the 24V external power supply into a 3.3V voltage for the 74HC245 chip interface circuit. The input data display circuit connects the external input signal to the 74HC245 chip interface circuit, and lights up the LED through the external input signal.

2. The microcontroller I / O circuit with an extended input interface according to claim 1, characterized in that, The 74HC245 chip has 20 pins, 16 of which are used for data transmission, and the remaining 4 are used for power and ground connections.

3. A microcontroller I / O circuit with an extended input interface according to claim 1, characterized in that, The 74HC245 chip has the following pins: pin 19 is the CS pin, pin 1 is the DIR pin, pins 2 to 9 are the data A transmission pins, and pins 11 to 18 are the data B transmission pins. When both the CS pin and the DIR pin are low, data is transmitted from B to A; When both the CS and DIR pins are high, data is transmitted from A to B; When the CS pin is high, the DIR level is in an isolated state, regardless of the fact that the CS pin is in a high level.

4. A microcontroller I / O circuit with an extended input interface according to claim 1, characterized in that, The 24V to 5V circuit includes the TPS5450DDAR chip circuit, which converts the external input voltage of 24V to 5V to provide the input voltage for the 5V to 3.3V circuit.

5. A microcontroller I / O circuit with an extended input interface according to claim 1, characterized in that, The 5V to 3.3V circuit includes an 1117 chip circuit, which converts the 5V output from the 24V to 5V circuit into 3.3V to provide voltage for the 74HC245 chip interface circuit.

6. A microcontroller I / O circuit with an extended input interface according to claim 1, characterized in that, The input data display circuit includes a TPL291-4 chip circuit. The TPL291-4 chip has input signal pins RTK+, RTK-, IN2, IN3, IN4, IN5, IN6, IN7, and IN8. The input signal pins IN2, IN3, IN4, IN5, IN6, IN7, and IN8 are respectively connected to the corresponding pins IN-1, IN-2, IN-3, IN-4, IN-5, IN-6, IN-7, and IN-8 of the 74HC245 chip. When the input signal is low, the LED in the TPL291-4 chip circuit is lit; when the input signal is high, the LED in the TPL291-4 chip circuit is not lit.

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