Waveform generator system based on single chip microcomputer

Abstract

The utility model belongs to the technical field of waveform generators, and especially relates to a waveform generator system based on a single-chip microcomputer, comprising a single-chip microcomputer, and a digital-to-analog conversion module, a band-pass filter module and a matrix keyboard module which are electrically connected with the single-chip microcomputer, the digital-to-analog conversion module is electrically connected with an oscilloscope; the band-pass filter module comprises a high-pass filter and a low-pass filter, the positive input end of the high-pass filter is connected with the single chip microcomputer, the output end of the high-pass filter is connected with the positive input end of the low-pass filter, and the output end of the low-pass filter is grounded; the band-pass filter module is used for filtering signal interference beyond a set frequency range, the digital-to-analog conversion module is used for performing digital-to-analog conversion on an output signal of the single chip microcomputer, and the oscilloscope is used for displaying a waveform signal. According to the waveform generator provided by the utility model, the single-chip microcomputer is used as a main controller, the stability of an output signal is increased by arranging the band-pass filtering module, signal interference outside a frequency range can be eliminated, and an output waveform is accurate and stable.

Description

Technical Field

[0001] The utility model belongs to the technical field of waveform generators, and in particular relates to a waveform generator system based on a single chip microcomputer. Background Art

[0002] The statements in this section merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] Waveform generators are important electronic instruments and are widely used in the field of electronic science. Especially in the technical fields of electrical engineering, communication engineering, automatic control, instrumentation, etc., waveform generators that can generate a variety of waveforms are often needed.

[0004] The core function of a waveform generator is to generate various types of electrical signal waveforms, including sine waves, square waves, and triangle waves. Since dedicated waveform generators are relatively expensive and have single functions, the market demand for waveform generators is low energy consumption, multi-function, and intelligent. The types of waveforms generated by traditional waveform generators are limited by circuit hardware, and their flexibility and stability are relatively poor. Utility Model Content

[0005] In order to overcome the above-mentioned deficiencies in the prior art, the utility model provides a waveform generator system based on a single chip microcomputer.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0007] The utility model provides a waveform generator system based on a single-chip microcomputer in a first aspect, comprising a single-chip microcomputer, a digital-to-analog conversion module, a bandpass filter module, a matrix keyboard module and an oscilloscope; the single-chip microcomputer is electrically connected to the digital-to-analog conversion module, the bandpass filter module and the matrix keyboard module respectively, and the digital-to-analog conversion module is electrically connected to the oscilloscope;

[0008] The bandpass filter module includes a high-pass filter and a low-pass filter, the positive input end of the high-pass filter is connected to the single-chip microcomputer, the output end is connected to the positive input end of the low-pass filter, and the output end of the low-pass filter is grounded;

[0009] The bandpass filter module is used to filter out signal interference outside a set frequency range, the digital-to-analog conversion module is used to perform digital-to-analog conversion on the output signal of the single-chip microcomputer, and the oscilloscope is used to display waveform signals.

[0010] Furthermore, the digital-to-analog conversion module includes a digital-to-analog conversion chip, a dual operational amplifier and a timer, and the digital-to-analog conversion chip is electrically connected to the timer and the oscilloscope respectively through the dual operational amplifier.

[0011] Furthermore, the current output pin IOUT1 of the digital-to-analog conversion chip is connected to the reverse input pin of the dual operational amplifier, and the current output pin IOUT2 ​​is connected to the forward input pin of the dual operational amplifier and then grounded; the output pin of the dual operational amplifier is connected to the feedback signal input pin of the digital-to-analog conversion chip, pin A of the oscilloscope, and the CLK pin of the timer.

[0012] Furthermore, the model of the digital-to-analog conversion chip is DAC0832.

[0013] Furthermore, the model of the dual operational amplifier is LM358.

[0014] Furthermore, the matrix keyboard module includes a matrix keyboard circuit and a switch control circuit, and the matrix keyboard circuit and the switch control circuit are respectively connected to the I / O port of the single-chip computer; the matrix keyboard circuit includes a waveform selection button and a frequency adjustment button, which are respectively used for waveform selection and frequency adjustment; the switch control circuit is used to switch the working state.

[0015] Furthermore, the waveform selection button includes a sawtooth wave selection button, a triangle wave selection button, a square wave selection button and a sine wave selection button, and each selection button is respectively connected to a corresponding frequency adjustment button.

[0016] Furthermore, the matrix keyboard circuit is a 4x4 matrix keyboard.

[0017] Furthermore, it also includes a liquid crystal display module, which is electrically connected to the single-chip computer and is used to display the waveform name and the waveform frequency.

[0018] Furthermore, the liquid crystal display module includes a liquid crystal display screen and a sliding resistor; the port En, port RW and port RS of the liquid crystal display screen are respectively connected to the corresponding ports of the single-chip microcomputer; the sliding end pin and the left pin of the sliding resistor are respectively connected to the pins of the liquid crystal display screen, and the right pin of the sliding resistor is connected to the power supply end.

[0019] One or more of the above technical solutions have the following beneficial effects:

[0020] (1) The waveform generator provided by the utility model uses a single-chip microcomputer as the main controller. By setting a bandpass filter module, the stability of the output signal is increased, and signal interference outside the frequency range can be eliminated. Finally, the output waveform is displayed on the simulation oscilloscope, and the output waveform is accurate and stable.

[0021] (2) The waveform generator provided by the utility model can select the type and frequency of the waveform signal through the matrix key module. The waveform type selection is highly flexible and the frequency adjustable range is large (10Hz-20Hz). In addition, the circuit structure is simple and the power consumption of the entire circuit system is low, which has wide applicability.

[0022] Advantages of additional aspects of the present invention will be partially given in the following description, and partially become apparent from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0024] Figure 1 This is a schematic diagram of a waveform generator system based on a single-chip microcomputer in Example 1.

[0025] Figure 2 1 is a circuit diagram of the single chip microcomputer of Example 1.

[0026] Figure 3 This is a circuit diagram of the digital-to-analog conversion module of Example 1.

[0027] Figure 4 This is a circuit diagram of a bandpass filter module of Example 1.

[0028] Figure 5 This is the circuit diagram of the matrix key module of Example 1.

[0029] Figure 6 This is a switch control circuit diagram of Example 1.

[0030] Figure 7 This is a circuit diagram of a liquid crystal display module according to Embodiment 1. DETAILED DESCRIPTION

[0031] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0032] Embodiment 1

[0033] like Figure 1 As shown, the utility model proposes a waveform generator system based on a single-chip microcomputer, including a single-chip microcomputer, a digital-to-analog conversion module, a band-pass filter module, a matrix keyboard module and an oscilloscope, the single-chip microcomputer is electrically connected to the digital-to-analog conversion module, the matrix keyboard module and the band-pass filter module respectively, and the digital-to-analog conversion module is electrically connected to the oscilloscope;

[0034] The bandpass filter module includes a high-pass filter and a low-pass filter, the positive input end of the high-pass filter is connected to the single-chip microcomputer, the output end is connected to the positive input end of the low-pass filter, and the output end of the low-pass filter is grounded;

[0035] The bandpass filter module is used to filter out signal interference outside the set frequency range, the digital-to-analog conversion module is used to perform digital-to-analog conversion on the output signal of the microcontroller, and the oscilloscope is used to display the waveform signal.

[0036] The matrix keyboard module is used to select the waveform type and frequency. The microcontroller receives the instructions issued by the matrix keyboard module and controls the peripheral circuits to generate waveform signals of different types and frequencies, and finally accurately displays the output waveform and waveform frequency on the simulation oscilloscope.

[0037] The digital-to-analog conversion module includes a digital-to-analog conversion chip, a dual operational amplifier and a timer. The digital-to-analog conversion chip is connected to the timer and the oscilloscope respectively through the dual operational amplifier.

[0038] The digital-to-analog conversion chip is used to perform digital-to-analog conversion on the output signal of the single-chip microcomputer. The analog current signal output by the digital-to-analog conversion chip is converted by the dual operational amplifier and output to the oscilloscope after the timing interrupt of the timer.

[0039] As a further technical solution, Figure 2 As shown, the model of the single-chip microcomputer is STM32F103R6 single-chip microcomputer. This chip supports multiple low-power modes, such as low-power operation mode, low-power standby mode, etc. The single-chip microcomputer system program is compiled in C language in Keil Uvision5 development environment.

[0040] Pin 7 of the STM32F103R6 microcontroller is connected to the power supply VCC / VDD; Pin 8, Pin 9, Pin 10, and Pin 11 of the STM32F103R6 microcontroller are electrically connected to Pin 7, Pin 6, Pin 5, and Pin 4 of the digital-to-analog conversion chip (corresponding to Port DI0, Port DI1, Port DI2, and Port DI3, respectively);

[0041] Pin 24, pin 25, pin 37 and pin 38 of the STM32F103R6 microcontroller are electrically connected to pin 16, pin 15, pin 14 and pin 13 of the digital-to-analog conversion chip (corresponding to port D14, port D15, port D16 and port D17, respectively);

[0042] Pin 29, Pin 35 and Pin 36 of the STM32F103R6 microcontroller are set as Port Key, Port S1 and Port S2 respectively. Pin 41, Pin 42, Pin 43, Pin 44, Pin 45 and Pin 46 of the STM32F103R6 microcontroller are set as Port RW, Port RS, Port En, Port CS1, Port Reset and Port CS2 respectively.

[0043] This embodiment uses the STM32F103R6 single-chip microcomputer as the CPU of the entire system. Due to its high performance, rich peripherals, low power design, and easy-to-use debugging and testing functions, it completes the calculation, processing, transmission and coordination of data between control modules by reading the corresponding designed system program.

[0044] The utility model uses the STM32F103 single-chip microcomputer as the main controller. After the system program is placed in the single-chip microcomputer chip, a command is issued by pressing a button, and the single-chip microcomputer receives the command and controls the peripheral circuit, thereby generating waveform signals of different types and frequencies, and finally accurately displays the output waveform on the simulation oscilloscope. The utility model has a simple circuit, high flexibility in waveform type selection, an adjustable frequency range (10Hz-20Hz), accurate and stable output waveforms, low power consumption of the entire circuit system, and wide applicability.

[0045] As a further technical solution, the digital-to-analog conversion module includes a digital-to-analog conversion chip, a dual operational amplifier, an oscilloscope and a timer, the dual operational amplifier is respectively connected to the digital-to-analog conversion chip, the oscilloscope and the timer, and the digital-to-analog conversion chip is connected to the single-chip microcomputer;

[0046] The matrix keyboard module is used to set the waveform type and frequency. After the single-chip microcomputer obtains the signal input by the matrix keyboard module, it generates a corresponding digital signal and sends it to the digital-to-analog conversion chip. The digital-to-analog conversion chip converts it into an analog current signal, which is then converted by a dual operational amplifier and output to the oscilloscope after the timer interrupt.

[0047] like Figure 3 As shown, the model of the digital-to-analog conversion chip is DAC0832, and the model of the dual operational amplifier is LM358; the digital-to-analog conversion chip is used to perform digital-to-analog conversion on the output signal of the single-chip microcomputer, and the dual operational amplifier is used to convert the analog current signal output by the digital-to-analog conversion chip.

[0048] Pin 1 and pin 2 of the DAC digital-to-analog conversion chip are both connected to port S1; pin 19 and pin 20 are both connected to the +5V power supply; pin 3 and pin 10 are both connected to the ground wire; and pin 8 is connected to the -8V power supply.

[0049] The reverse input pin (pin 6) of the LM358 dual operational amplifier is connected to the current output pin IOUT1 (pin 11) of the DAC0832 digital-to-analog conversion chip; the positive input pin (pin 5) and the current output pin IOUT2 ​​(pin 12) of the DAC0832 digital-to-analog conversion chip are both connected to the ground wire, the negative power pin (pin 4) of the dual operational amplifier is connected to the -12V power supply, the positive power pin (pin 8) is connected to the +12V power supply, and the output pin (pin 7) of the dual operational amplifier is connected to pin 9 of the DAC0832 digital-to-analog conversion chip, pin A of the oscilloscope, and the CLK pin of the timer.

[0050] The oscilloscope is used to display waveform signals. The oscilloscope supports four signal input channels, namely A, B, C and D. Any one or more channels can be selected as needed.

[0051] The timing interrupt signal output by the timer acts on the microcontroller chip through the DAC0832 digital-to-analog conversion chip; the timer is equipped with pins CLK, CE and RST, where CLK is the clock signal input terminal (CLOCK), CE (counterenable) is the count enable terminal, and the counting mode is controlled by different high and low levels. RST is the count / timing reset terminal (Reset), which resets the count / timing.

[0052] This embodiment uses the DAC0832 chip to perform DA conversion. The DAC0832 divides the output voltage into 0xFF (255) parts. Different waveforms need to be output with different data. For example, a cycle of all waveforms is divided into 100 parts, and the timer is interrupted once at a certain interval, and 100 interruptions constitute a cycle.

[0053] The sine wave is calculated using the mathematical function sin and sent to the microcontroller for data processing. The data after the microcontroller calculation is sent to the DAC0832 chip to convert the digital signal into an analog output. The square wave only needs to be given 0 50 times in the first 50 times of the timer and the maximum value in the last 50 times. The triangle wave only needs to multiply itself by 1 / 50 of the maximum value in the first 50 times of the timer, and vice versa for the last 50 times. The sawtooth wave only needs to multiply itself by 1 / 100 of the maximum voltage once the timer is interrupted within one cycle.

[0054] As a further technical solution, Figure 4 As shown, the bandpass filter module includes a high-pass filter and a low-pass filter connected in sequence, wherein the high-pass filter is composed of an operational amplifier U1, a resistor R1 and a capacitor C1, and the cut-off frequency is f=10Hz; the low-pass filter is composed of an operational amplifier U2, a resistor R2 and a capacitor C2, and the cut-off frequency is f=20Hz. The values ​​of the resistor R and the capacitor C can be obtained by the formula f=1 / 2πRC. Based on miniaturization and cost considerations, a first-order high-pass filter and a first-order low-pass filter are used.

[0055] The same-direction input terminal (pin 3) of the operational amplifier U1 is connected to the 34th pin (S3 port) of the single-chip computer through the capacitor C1 (1.6uF) and connected to the grounding resistor R1 (10k) in one way; the reverse input terminal (pin 2) of the operational amplifier U1 is connected to the output terminal (pin 1) of the operational amplifier U1; the pins 4 and 8 of the operational amplifier U1 are connected to the power port -12v and the power port +12v respectively; the output terminal (pin 1) of the operational amplifier U1 is connected to the same-direction input terminal (pin 3) of the operational amplifier U2 through the resistor R2 (15k);

[0056] The non-inverting input terminal (pin 3) of the operational amplifier U2 is also connected to the grounding capacitor C2 (0.5uF); pin 4 and pin 8 of the operational amplifier U2 are respectively connected to the power port -12v and the power port +12v; the reverse input terminal (pin 2) of the operational amplifier U2 is connected to the output terminal (pin 1) of the operational amplifier U2; the output terminal (pin 1) of the operational amplifier U2 is grounded.

[0057] In this embodiment, in order to increase the stability of the output signal and eliminate signal interference outside the frequency range (10Hz-20Hz), a bandpass filter module is set; the function of the bandpass filter is to allow signals within a specific frequency range to pass, but to shield signals above and below the frequency range.

[0058] As a further technical solution, the matrix keyboard module includes a matrix keyboard circuit and a switch control circuit, and the matrix keyboard circuit and the switch control circuit are respectively connected to the I / O port of the microcontroller; the matrix keyboard circuit includes a waveform selection button and a frequency adjustment button, which are respectively used to adjust the waveform and frequency; the switch control circuit is used to switch the system working state.

[0059] The waveform selection buttons include a sawtooth wave selection button, a triangle wave selection button, a square wave selection button, and a sine wave selection button, and each selection button is connected to a corresponding frequency adjustment button. In this embodiment, the system flexibility is enhanced by designing a matrix keyboard circuit, and the type and frequency of the output waveform can be changed by clicking different buttons.

[0060] like Figure 5 As shown, the matrix keyboard circuit includes 16 keys, among which the left pins of key D, key C, key B and key A are all connected to port R3;

[0061] The left pins of button #, button 9, button 6 and button 3 are all connected to port R2 (pin 58) of the STM32F103R6 microcontroller;

[0062] The left pins of button 0, button 8, button 5 and button 2 are all connected to port R1 (pin 57) of the STM32F103R6 microcontroller;

[0063] The left pins of button *, button 7, button 4 and button 1 are all connected to port R0 (pin 56) of the STM32F103R6 microcontroller;

[0064] The right pins of button D, button #, button 0 and button * are all connected to port C3 (pin 55) of the STM32F103R6 microcontroller;

[0065] The right pins of button C, button 9, button 8 and button 7 are all connected to port C2 (pin 28) of the STM32F103R6 microcontroller;

[0066] The right pins of Button B, Button 6, Button 5 and Button 4 are all connected to Port C1 (Pin 27) of the STM32F103R6 microcontroller;

[0067] The right pins of Button A, Button 3, Button 2 and Button 1 are all connected to Port C0 (Pin 26) of the STM32F103R6 microcontroller;

[0068] Button D, button C, button B and button A are used to switch sawtooth wave, triangle wave, square wave and sine wave respectively; button # and button * are used to switch frequency addition / subtraction respectively;

[0069] In this embodiment, the keyboard circuit uses a 4x4 matrix keyboard, and the type and frequency of the waveform output by the function waveform generator can be realized by pressing different keys; the 4x4 matrix keyboard has the advantages of compact design, easy integration and pin saving.

[0070] The basis for the microcontroller to detect the key is whether the I / O port corresponding to the key is at a low level. Once a key is pressed, the matrix keyboard circuit enters the delay state. The microcontroller can know whether a key is pressed by reading the state of the input line, and then judge which row is pressed, and then judge which column is pressed, and finally determine the data output.

[0071] like Figure 6 As shown, the upper pin of the switching switch Key in the switch control circuit is connected to the +3.3V power supply, the lower pin is connected to the resistor R1, and the other pin of the resistor R1 is connected to the ground line.

[0072] In this embodiment, the working state of the system is adjusted by turning the state switching switch on and off. The working state of the system includes two states, one is an adjustment mode state, and the other is a waveform output mode state.

[0073] For example, if you need to switch to a sine wave waveform, first click the switch in the matrix keyboard circuit module to put the system into the adjustment mode state; if you need to adjust the waveform frequency of the waveform generator system, click the keys # and * in the matrix keyboard circuit to increase or decrease the frequency of the output waveform, and the adjustable range is 10Hz-20Hz. Then click the key A in the matrix keyboard circuit, and then click the switch to put the system into the waveform output mode state. Finally, after debugging and simulation, a sine wave waveform can be obtained.

[0074] The waveform generator system provided by the utility model can quickly and accurately generate a specified waveform signal, and has good anti-interference performance and convenient control. The waveform generator system can be applied to scenes such as experimental teaching and equipment testing. It works reliably and has low power consumption, and has wide applicability.

[0075] As a further technical solution, it also includes a liquid crystal display module, which is electrically connected to the single-chip computer and is used to display the waveform name and waveform frequency.

[0076] The liquid crystal display module includes a liquid crystal display screen and a sliding rheostat. The model of the liquid crystal display screen is LCD12864. Port En, port RW and port RS of the liquid crystal display screen are respectively connected to corresponding ports of the microcontroller. The sliding end pin and the left pin of the sliding rheostat are connected to the liquid crystal display, and the right pin is connected to the power supply end.

[0077] like Figure 7 As shown, pin 1 and pin 2 (port CS1 and port CS2, respectively) of the LCD12864 liquid crystal display are electrically connected to pin 44 and pin 46 of the STM32F103R6 microcontroller, respectively. Pin 3 of the liquid crystal display is connected to the ground wire, and pin 4 is connected to the power supply terminal VCC / VDD.

[0078] Pin 16, pin 15, pin 14, pin 13, pin 12, pin 11, pin 10 and pin 9 of the LCD display (set as port D7, port D6, port D5, port D4, port D3, port D2, port D1 and port D0 respectively) are electrically connected to pin 14, pin 15, pin 16, pin 17, pin 20, pin 21, pin 22 and pin 23 of the STM32F103R6 microcontroller respectively.

[0079] Pin 8, pin 7 and pin 6 of the LCD display (port En, port RW and port RS respectively) are electrically connected to pin 43, pin 41 and pin 42 of the STM32F103R6 microcontroller respectively; pin 17 (port Reset) of the LCD display is electrically connected to pin 45 of the STM32F103R6 microcontroller.

[0080] Pin 18 of the LCD12864 liquid crystal display is connected to the left pin of the sliding resistor RV1; the right pin of the sliding resistor RV1 is connected to the power supply terminal VCC / VDD; the sliding end pin of the sliding resistor RV1 is connected to pin 5 of the LCD12864 liquid crystal display.

[0081] In this embodiment, the LCD12864 liquid crystal display is a common 128x64 pixel graphic dot matrix liquid crystal display screen, and each pixel can control the brightness or darkness of the display point to display text, icons and simple graphics.

[0082] LCD12864 can be connected to the controller via a parallel interface or a serial interface. A parallel interface usually uses multiple pins and can provide faster data transmission speed, while a serial interface requires fewer pins and is suitable for application scenarios with limited resources. In order to increase the simulation speed, this embodiment adopts a parallel mode.

[0083] The working principle of this embodiment is:

[0084] After the system is initialized, the type and frequency of the output signal waveform are selected by pressing the buttons. According to the user's instructions, the microcontroller converts the output frequency signal through the DAC0832 digital-to-analog conversion circuit, outputs the interrupt signal through the timer, filters out clutter interference through the filter module, and buffers the output through the dual operational amplifier. Finally, the output waveform is accurately displayed on the simulation oscilloscope, and the name of the waveform type and the waveform frequency value can be displayed on the LCD12864 display.

[0085] Although the above describes the specific implementation methods of the utility model in combination with the accompanying drawings, it is not intended to limit the scope of protection of the utility model. Technical personnel in the relevant field should understand that on the basis of the technical solution of the utility model, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the utility model.

Claims

1. A waveform generator system based on a single chip microcomputer, characterized in that: It includes a single-chip microcomputer, a digital-to-analog conversion module, a band-pass filter module, a matrix keyboard module and an oscilloscope; the single-chip microcomputer is electrically connected to the digital-to-analog conversion module, the band-pass filter module and the matrix keyboard module respectively, and the digital-to-analog conversion module is electrically connected to the oscilloscope; The bandpass filter module includes a high-pass filter and a low-pass filter, the positive input end of the high-pass filter is connected to the single-chip microcomputer, the output end is connected to the positive input end of the low-pass filter, and the output end of the low-pass filter is grounded; The bandpass filter module is used to filter out signal interference outside the set frequency range, the digital-to-analog conversion module is used to perform digital-to-analog conversion on the output signal of the single-chip microcomputer, and the oscilloscope is used to display the waveform signal; The bandpass filter module includes a high-pass filter and a low-pass filter connected in sequence, wherein the high-pass filter is composed of an operational amplifier U1, a resistor R1 and a capacitor C1, and the cut-off frequency is f=10Hz; the low-pass filter is composed of an operational amplifier U2, a resistor R2 and a capacitor C2, and the cut-off frequency is f=20Hz; The digital-to-analog conversion module includes a digital-to-analog conversion chip, a dual operational amplifier and a timer. The digital-to-analog conversion chip is electrically connected to the timer and the oscilloscope through the dual operational amplifier respectively; the analog current signal output by the digital-to-analog conversion chip is output to the oscilloscope after conversion by the dual operational amplifier and timing interruption of the timer.

2. A waveform generator system based on a single chip microcomputer according to claim 1, characterized in that: The current output pin IOUT1 of the digital-to-analog conversion chip is connected to the reverse input pin of the dual operational amplifier, and the current output pin IOUT2 ​​is connected to the forward input pin of the dual operational amplifier and then grounded; the output pin of the dual operational amplifier is connected to the feedback signal input pin of the digital-to-analog conversion chip, pin A of the oscilloscope, and the CLK pin of the timer.

3. A waveform generator system based on a single chip microcomputer according to claim 1, characterized in that: The model of the digital-to-analog conversion chip is DAC0832.

4. A waveform generator system based on a single chip microcomputer according to claim 1, characterized in that: The model of the dual operational amplifier is LM358.

5. A waveform generator system based on a single chip microcomputer according to claim 1, characterized in that: The matrix keyboard module includes a matrix keyboard circuit and a switch control circuit, and the matrix keyboard circuit and the switch control circuit are respectively connected to the I / O port of the single-chip computer; the matrix keyboard circuit includes a waveform selection button and a frequency adjustment button, which are respectively used for waveform selection and frequency adjustment; the switch control circuit is used for switching the working state.

6. A waveform generator system based on a single chip microcomputer according to claim 5, characterized in that: The waveform selection buttons include a sawtooth wave selection button, a triangle wave selection button, a square wave selection button and a sine wave selection button, and each selection button is respectively connected to a corresponding frequency adjustment button.

7. A waveform generator system based on a single chip microcomputer according to claim 5, characterized in that: The matrix keyboard circuit is a 4x4 matrix keyboard.

8. A waveform generator system based on a single chip microcomputer according to claim 1, characterized in that: It also includes a liquid crystal display module, which is electrically connected to the single-chip computer and is used to display the waveform name and the waveform frequency.

9. A waveform generator system based on a single chip microcomputer according to claim 8, characterized in that: The liquid crystal display module includes a liquid crystal display screen and a sliding rheostat; the port En, port RW and port RS of the liquid crystal display screen are respectively connected to the corresponding ports of the single-chip microcomputer; the sliding end pin and the left pin of the sliding rheostat are respectively connected to the pins of the liquid crystal display screen, and the right pin of the sliding rheostat is connected to the power supply end.

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