Multi-bit LED nixie tube display circuit with high anti-interference capability and keys

Abstract

The utility model provides a multi-bit LED nixie tube display circuit with strong anti-interference capability and keys, which comprises a key scanning circuit, a single-chip microcomputer and an LED nixie tube driving module, the key scanning circuit comprises a plurality of keys and decoupling capacitors, each key is connected to the single-chip microcomputer through the decoupling capacitor, and the LED nixie tube driving module is connected with the single-chip microcomputer through the single-chip microcomputer. The LED nixie tube driving module comprises an LED nixie tube group and an LED driving chip, the LED nixie tube group is connected with the LED driving chip, the LED driving chip is connected with the single-chip microcomputer, and the single-chip microcomputer communicates with a main control chip of the instrument equipment through a serial port. According to the utility model, display of more nixie tubes can be realized, connection to a main control chip of instrument equipment by using fewer leads is realized, verification of transmission data is realized, the accuracy of display information and key states is ensured, and the anti-interference capability is strong.

Description

Technical Field

[0001] The utility model relates to the technical field of digital tube display, in particular to a multi-digit LED digital tube display circuit with strong anti-interference ability and keys. Background Art

[0002] The multi-digit digital tube display circuit with buttons has the characteristics of high display brightness, low power consumption, simple driving and easy operation. Therefore, the multi-digit digital tube display circuit with buttons has been widely used in many measurement and control instrument equipment. It is an indispensable circuit for realizing human-computer exchange. Through the display circuit, the relevant information of the instrument equipment can be intuitively provided to the user, so that the user can simply and intuitively understand the working status of the instrument equipment, or the fault and cause of the equipment can be promptly fed back to the user through the flashing of the display, so that the user can analyze and solve the fault in time. Through the buttons, the user can easily set various parameters of the instrument equipment, so that the instrument equipment can realize different functions.

[0003] Currently, there are generally two ways to implement multi-digit digital tube display circuits with buttons. One is that the main control chip of the instrument equipment directly drives the code tube display and scanning buttons through the IO port. This method occupies more IO ports of the main control chip of the instrument equipment and can display fewer digital tube digits; the other is that the main control chip of the instrument equipment drives the code tube display and scanning buttons through the shift register chip and the decoder. This method occupies fewer IO ports of the main control chip of the instrument equipment and can drive more digital tubes, but the circuit is complex, the digital tube display refresh rate is slow, and its anti-interference ability is weak. In the case of electromagnetic interference, the digital tube display will be chaotic or missing segments, and the key circuit will also be unstable, and the keys will malfunction. Utility Model Content

[0004] In order to solve the above problems, the utility model provides a multi-digit LED digital tube display circuit with strong anti-interference ability and buttons, including a button scanning circuit, a single-chip microcomputer and an LED digital tube driving module, wherein the button scanning circuit and the LED digital tube driving module are both connected to the single-chip microcomputer, and the single-chip microcomputer communicates with the main control chip of the instrument equipment through a serial port;

[0005] The key scanning circuit includes a plurality of keys and a decoupling capacitor, and each key is connected to the single chip microcomputer via the decoupling capacitor;

[0006] The LED digital tube driving module includes an LED digital tube group and an LED driving chip, wherein the LED digital tube group is connected to the LED driving chip, and the LED driving chip is connected to the single chip microcomputer;

[0007] Each light emitting diode of the LED digital tube group is connected to a segment driving pin of the LED driving chip via a current limiting resistor.

[0008] Optionally, the LED driver chip model is TM1681, and the single chip microcomputer model is STC15W408S.

[0009] The beneficial effects of the utility model compared with the prior art are:

[0010] 1. This circuit can realize the display of up to 28 digital tubes, which meets the current user's demand for multi-digit digital tube display;

[0011] 2. This circuit can be connected to the main control chip of the instrument equipment with fewer wires, which meets the current user's demand for simple connection between modules;

[0012] 3. This circuit can verify the transmitted data and filter out the error information, which meets the current user's demand for high stability and high accuracy of display;

[0013] 4. This circuit can have strong anti-interference ability, which meets the current user's demand for instrument equipment to adapt to harsh working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0015] Figure 1 This is a structural block diagram of a multi-digit LED digital tube display circuit with strong anti-interference ability and buttons;

[0016] Figure 2 It is a structural diagram of the key scanning circuit part;

[0017] Figure 3 This is the pin diagram of the LED digital tube group;

[0018] Figure 4 This is the pin diagram of the LED driver chip;

[0019] Figure 5 This is the microcontroller pin diagram. DETAILED DESCRIPTION

[0020] The embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0021] With the development of society and the rapid progress of industrial automation, people have put forward higher and higher requirements on the display digits and display effects of digital tube display circuits. The traditional digital tube display circuits are increasingly unsuitable for the display requirements of current instrument equipment, which is mainly reflected in the following problems:

[0022] 1. There is a problem of occupying too many IO ports of the main control chip of the instrument equipment. If the main control chip of the instrument equipment directly drives 5 digital tubes through the IO port, 13 IO ports are required, including 8 for segment selection and 5 for bit selection. For the main control chip of general instrument equipment, such pin usage accounts for too large a proportion, which will lead to insufficient IO ports available for the main control chip of the instrument equipment in other functional modules;

[0023] 2. The display refresh rate is slow. When the main control chip of the instrument equipment controls the refresh, only one digit can be lit each time and it must be maintained for a certain period of time. When the digital tube displays a large number of digits, it can only be refreshed about 3 times per second, resulting in slow response of the user's instrument equipment;

[0024] 3. The problem of weak anti-interference ability. When the main control chip of the instrument equipment communicates with the shift register, there are only two lines, a clock line and a data line. When these two lines are long, external electromagnetic interference will cause the clock signal and the data signal to mutate, resulting in communication errors and garbled display. When the connection line between the key circuit and the main control chip of the instrument equipment is long, the key circuit sampling will also be unstable, which can easily lead to key misoperation.

[0025] After research, the inventor adopts a method of combining a single-chip microcomputer with a dedicated LED driver chip. The single-chip microcomputer communicates with the main control chip of the instrument equipment through a serial port to transmit display information and key status, and performs data verification in the single-chip microcomputer, thereby ensuring the accuracy of the display information and key status; the single-chip microcomputer is also responsible for key sampling and obtaining the status of the keys; the single-chip microcomputer is responsible for communicating with the LED driver chip and transmitting the display content to the corresponding register of the LED driver chip; the use of a dedicated LED driver chip can drive two digital tubes at a time, thereby reducing the scanning time and increasing the refresh rate; in the PCB layout, the single-chip microcomputer and the key are arranged close, and the connecting wire is short, thereby reducing external interference with the key scanning, and the single-chip microcomputer and the LED driver chip are placed close to each other, reducing the length of the communication line, thereby reducing external interference with the LED driver chip clock signal and data signal, making the display more stable.

[0026] like Figure 1 As shown, a multi-digit LED digital tube display circuit with strong anti-interference ability and with buttons provided in an embodiment of the present disclosure includes a button scanning circuit, a single-chip microcomputer and an LED digital tube driving module, wherein the button scanning circuit is connected to the single-chip microcomputer, the LED digital tube driving module includes an LED digital tube group and an LED driving chip, the LED digital tube group is connected to the LED driving chip, the LED driving chip is connected to the single-chip microcomputer, and the single-chip microcomputer communicates with a main control chip of an instrument device through a serial port;

[0027] refer to Figure 2 The key scanning circuit includes 5 keys and 5 decoupling capacitors. The keys K1, K2, K3, K4, and K5 are connected to the single-chip microcomputer on the multi-digit digital tube display circuit through the decoupling capacitors C1, C3, C4, C5, and C6. After multiple judgments by the internal program of the single-chip microcomputer, the accurate key status is transmitted to the main control chip of the instrument equipment through the serial port, thereby further realizing the key operation function of the instrument equipment;

[0028] refer to Figure 3 and Figure 4The LED digital tube group consists of 4 5-bit digital tubes and 2 groups of single LED lights. The use of 5-bit digital tubes can greatly reduce the number and difficulty of wiring when drawing the PCB board. C2, C8, and C9 are decoupling capacitors. Each light-emitting diode of the LED digital tube group is connected to the segment drive pin of the LED driver chip through a current-limiting resistor. The LED driver chip U1 uses TM1681. The LED driver chip U1 has 24-bit segment drive pins and 16-bit bit drive pins. The LED driver chip is a chip that can run independently. The segment drive pins and bit drive pins can be enabled respectively according to its internal register values. In this circuit, the LED driver chip only drives 28 digital tubes, and only 16-bit segment drive pins and 16-bit bit drive pins are used. The LED driver chip drives 16-bit segment pins and 1 bit pin at the same time each time, so that 2 digital tubes can be driven at one time. When all 16 bit pins are scanned once, the digital tube will light up once. The scanning frequency of the LED driver chip can reach 80 times per second.

[0029] refer to Figure 5 The single-chip microcomputer adopts STC15W408S. The single-chip microcomputer is connected to the LED driver chip through the CS, RD, WR, and DATA pins, and transmits the data to be displayed to the LED digital tube driver module through these four pins. The single-chip microcomputer is connected to the buttons K1, K2, K3, K4, and K5 through the KEY1, KEY2, KEY3, KEY4, and KEY5 pins. The state of the buttons is obtained by continuously sampling the high and low levels of these five pins, and transmitted to the main control chip of the instrument equipment through the serial port. The single-chip microcomputer is connected to the main control chip of the instrument equipment through the RXD, TXD, and GND pins, and communicates with the main control chip of the instrument equipment through the RXD and TXD pins. For example, the single-chip microcomputer can transmit the button state to the main control chip of the instrument equipment, and the main control chip of the instrument equipment can transmit the content to be displayed to the single-chip microcomputer, which is then converted by the single-chip microcomputer into the information required by the LED digital tube driver module and transmitted to the LED driver chip, thereby driving the LED digital tube group to display the corresponding information.

[0030] The exemplary implementation of the satellite solar array shunt power storage and conversion circuit proposed in the utility model is described in detail above with reference to the preferred embodiments. However, those skilled in the art will appreciate that, without departing from the concept of the utility model, various modifications and alterations may be made to the above-mentioned specific embodiments, and various technical features and structures proposed in the utility model may be combined in various ways without exceeding the protection scope of the utility model, which is determined by the appended claims.

Claims

1. A multi-digit LED digital tube display circuit with strong anti-interference ability and buttons, characterized in that: It includes a key scanning circuit, a single-chip microcomputer and an LED digital tube driving module, wherein the key scanning circuit and the LED digital tube driving module are both connected to the single-chip microcomputer, and the single-chip microcomputer communicates with the main control chip of the instrument equipment through a serial port; The key scanning circuit includes a plurality of keys and a decoupling capacitor, and each key is connected to the single chip microcomputer via the decoupling capacitor; The LED digital tube driving module includes an LED digital tube group and an LED driving chip, wherein the LED digital tube group is connected to the LED driving chip, and the LED driving chip is connected to the single chip microcomputer; Each light emitting diode of the LED digital tube group is connected to a segment driving pin of the LED driving chip via a current limiting resistor.

2. The multi-digit LED digital tube display circuit with strong anti-interference ability and buttons according to claim 1 is characterized in that: The LED driver chip model is TM1681, and the single chip microcomputer model is STC15W408S.

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