Intelligent keyboard with external code scanner

Abstract

This application relates to the field of input keyboards, and particularly to an intelligent keyboard for an external barcode scanner. It includes a main control module, an auxiliary control module, a matrix keyboard module, and an LCD display module. The auxiliary control module is used for data transmission with the barcode scanner, and the matrix keyboard module is used for key input. The LCD display module is used to display key data and transaction data sent by the main control module. The main control module includes a chip U5 and a bypass circuit. The auxiliary control module includes a chip U6, resistors R26, R27, and R28, capacitors C30 and C31, and a key X17. This application provides an intelligent keyboard for an external barcode scanner, which, through keyboard input of transaction amounts and cooperation with the barcode scanner, enables mobile payment collection.

Description

Technical Field

[0001] This application relates to the field of input keyboards, and more particularly to a smart keyboard for an external barcode scanner. Background Technology

[0002] Existing barcode scanners cannot work independently and must be equipped with a cash register terminal. Furthermore, barcode scanners are not portable and are inconvenient to operate. Summary of the Invention

[0003] In view of this, this application provides a smart keyboard for an external barcode scanner, which enables mobile payment collection by inputting the transaction amount through the keyboard in conjunction with the barcode scanner.

[0004] To achieve the above objectives, this application employs the following technical solution:

[0005] A smart keyboard for an external barcode scanner is characterized by comprising a main control module and an auxiliary control module, a matrix keyboard module, and an LCD display module connected to the main control module; the auxiliary control module is used for data transmission with the barcode scanner and for acquiring and transmitting transaction data back to the main control module; the matrix keyboard module is used for key input, and the main control module transmits the key input from the matrix keyboard module to the barcode scanner through the auxiliary control module; the LCD display module is used to display the key input and transaction data sent by the main control module.

[0006] The main control module includes a chip U5 and a bypass circuit. The chip U5 is an AIR780EP chip. The bypass circuit includes capacitors C18, C19, C20 and C21 connected in parallel. One end of the parallel circuit is grounded and the other end is connected to pins 42 and 43 of U5 respectively.

[0007] The auxiliary control module includes chip U6, resistors R26, R27, and R28, capacitors C30 and C31, and button X17.

[0008] The chip U6 is a CH554G chip. The chip U6 is connected to the barcode scanner via USB, and the chip U6 communicates with the chip U5 via a serial port. One end of the resistor R26 is connected to pin 4 of the chip U6, and the other end is connected to the UART3_TXD terminal of the chip U5. One end of the resistor R27 is connected to pin 5 of the chip U6, and the other end is connected to the UART3_RXD terminal of the chip U5. One end of the resistor R28 is connected to pin 12 of the chip U6, and the other end is connected to button X17. One end of the capacitor C30 is grounded, and the other end is connected to pin 16 of the chip U6 and the 3.3V power supply terminal. One end of the capacitor C31 is grounded, and the other end is connected to pin 15 of the chip U6 and the 3.3V power supply terminal.

[0009] The aforementioned application describes an intelligent keyboard for an external barcode scanner. This keyboard can display transaction data and allows users to input transaction amounts via buttons. When paired with an existing barcode scanner box, it enables mobile payment collection and is easy to operate.

[0010] In some implementations, the matrix keyboard module is a 4x4 matrix keyboard, which uses 8 I / O ports to determine 16 keys.

[0011] In some embodiments, the smart keyboard also includes a power amplifier module for outputting audio signals of transaction data sent by the main control module; the power amplifier module includes a digital signal to audio signal conversion circuit and an audio signal amplification circuit.

[0012] The digital signal to audio signal circuit is used to convert the digital signal transmitted by the main control module into an analog audio signal. The digital signal to audio signal circuit includes chip U8, resistor R36, capacitor C39, capacitor C40, capacitor C42 and capacitor C43.

[0013] The chip U8 is an ES7111 chip. One end of capacitor C39 is connected to pin 1 of chip U8 and the 3.3V power supply terminal, and the other end of capacitor C39 is grounded. One end of capacitor C42 is connected to pin 5 of chip U8, and the other end of capacitor C42 is grounded. One end of capacitor C43 is connected to pin 6 of chip U8 and the 3.3V power supply terminal, and the other end of capacitor C43 is grounded. One end of capacitor C40 is connected to pin 10 of chip U8 and the 3.3V power supply terminal, and the other end of capacitor C40 is grounded. One end of resistor R36 is grounded, and the other end is also grounded.

[0014] The audio signal amplification circuit is used to amplify analog audio signals. The audio signal amplification circuit includes chip U9, resistors R34, R35, and R37, capacitors C41, C44, C45, C46, ​​C47, and C48, and connector J5.

[0015] The chip U9 is a 4150C chip; pin 8 of the chip U8 is connected to one end of capacitor C41, the other end of capacitor C41 is connected to one end of resistor R34, and the other end of resistor R34 is connected to pin 3 of the chip U9; pin 7 of the chip U8 is connected to one end of capacitor C44, the other end of capacitor C44 is connected to one end of resistor R35, and the other end of resistor R35 is connected to pin 4 of the chip U9; one end of capacitor C45 is grounded and the other end is connected to pin 2 of the chip U9; the AUDIO_CS terminal is connected to one end of resistor R37, the other end of resistor R37 is connected to one end of capacitor C46 and pin 1 of the chip U9, and the other end of capacitor C46 is grounded; capacitors C47 and C48 are connected in parallel, with one end of the parallel circuit grounded and the other end connected to pin 6 of the chip U9; pin 1 of connector J5 is connected to pin 8 of the chip U9; pin 2 of connector J5 is connected to pin 5 of the chip U9.

[0016] In some embodiments, the liquid crystal display module includes a backlight control circuit and a display connection circuit;

[0017] The backlight control circuit includes resistors R46, R47, R48, and R49, transistor Q1, and connector J6. The LCD_CTL terminal is connected to one end of resistor R46. The other end of resistor R46 is connected to one end of resistor R47 and the base of transistor Q1. The other end of resistor R47 is grounded. The emitter of transistor Q1 is grounded. The collector of transistor Q1 is connected to pin 1 of connector J6. Resistors R48 and R49 are connected in parallel. One end of this parallel circuit is connected to the 3.3V power supply. The other end of resistor R49 is connected to pin 2 of connector J6. Connectors G2 and G1 of connector J6 are grounded.

[0018] The display connection circuit includes a resistor R50, a capacitor C50, a capacitor C51, a capacitor C52, a capacitor C49, and a connector J7; one end of capacitor C52 is grounded and the other end is connected to pin 1 of connector J7; one end of capacitor C51 is connected to pin 2 of connector J7 and the other end is connected to pin 3 of connector J7; one end of capacitor C50 is connected to pin 4 of connector J7 and the other end is connected to pin 5 of connector J7; one end of capacitor C49 is grounded and the other end is connected to pin 7 of connector J7 and the 3.3V power supply terminal; one end of resistor R50 is connected to the 3.3V terminal and the other end is connected to pin 11 of connector J7.

[0019] In some embodiments, the smart keyboard also includes a WIFI module; the WIFI module includes a chip U7, resistors R29, R30, R31, R32, and R33, capacitors C36, C37, C38, C32, C33, C34, and C35, a crystal oscillator Y1, and an inductor L2.

[0020] The chip U7 is a YC1178 chip; the UART1_RXD terminal is connected to one end of resistor R29, and the other end of resistor R29 is connected to pin 6 of chip U7; the UART1_TXD terminal is connected to one end of resistor R30, and the other end of resistor R30 is connected to pin 7 of chip U7; the UART1_RTS terminal is connected to one end of resistor R31, and the other end of resistor R31 is connected to pin 8 of chip U7; the UART1_CTS terminal is connected to one end of resistor R32, and the other end of resistor R32 is connected to pin 9 of chip U7; one end of resistor R33 is grounded and the other end is connected to pin 11 of chip U7; one end of capacitor C36 is grounded and the other end is connected to… Connect one end of the capacitor C37 to pin 14 of chip U7; connect one end of capacitor C37 to pin 15 of chip U7 and pin 1 of crystal oscillator Y1 respectively; connect pins 2 and 4 of crystal oscillator Y1 to pin 16 of chip U7 and capacitor C38 respectively, and connect the other end of capacitor C38 to pin 14 of chip U7; connect one end of capacitor C32 to pin 21 of chip U7; connect one end of capacitor C33 to pins 19 and 20 of chip U7 and the 3.3V power supply terminal respectively; connect one end of capacitor C34 to pin 18 of U7 and one end of inductor L2 respectively; connect one end of capacitor C35 to the other end of inductor L2.

[0021] As can be seen from the above technical solution, this application has at least the following advantages and positive effects:

[0022] This application discloses a smart keyboard for an external barcode scanner. The smart keyboard of the external barcode scanner can display transaction data and allow users to input transaction amounts by pressing buttons. When used with an existing barcode scanner box, it enables mobile payment collection and is easy to operate. Attached Figure Description

[0023] Figure 1 The circuit of the main control module in the embodiments of this application Figure 1 ;

[0024] Figure 2 The circuit of the main control module in the embodiments of this application Figure 2 ;

[0025] Figure 3 This is a circuit diagram of the auxiliary control module in an embodiment of this application;

[0026] Figure 4 This is a circuit diagram of the power amplifier module in an embodiment of this application;

[0027] Figure 5 This is a circuit diagram of the display module in an embodiment of this application;

[0028] Figure 6 This is a circuit diagram of the matrix keyboard module in an embodiment of this application;

[0029] Figure 7 This is a circuit diagram of the WIFI module in an embodiment of this application. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the application will be described in further detail below with reference to the accompanying drawings. The terminology used in the embodiments section of this application is only for explaining specific embodiments and is not intended to limit the application.

[0031] See Figures 1 to 6 This application provides an intelligent keyboard for an external barcode scanner, including a main control module and an auxiliary control module, a matrix keyboard module, and an LCD display module connected to the main control module. The auxiliary control module is used for data transmission with the barcode scanner and for acquiring and transmitting transaction data back to the main control module. The matrix keyboard module is used for key input, and the main control module transmits the key input from the matrix keyboard module to the barcode scanner through the auxiliary control module. The LCD display module is used to display the key input and transaction data sent by the main control module.

[0032] The main control module includes a chip U5 and a bypass circuit. The chip U5 is an AIR780EP chip. The bypass circuit includes capacitors C18, C19, C20 and C21 connected in parallel. One end of the parallel circuit is grounded and the other end is connected to pins 42 and 43 of U5 respectively.

[0033] The auxiliary control module includes chip U6, resistors R26, R27, and R28, capacitors C30 and C31, and button X17.

[0034] The chip U6 is a CH554G chip. Chip U6 connects to the barcode scanner via USB and communicates with chip U5 via serial port, enabling data exchange through the serial port protocol. One end of resistor R26 is connected to pin 4 of chip U6, and the other end is connected to the UART3_TXD terminal (pin 52) of chip U5. One end of resistor R27 is connected to pin 5 of chip U6, and the other end is connected to the UART3_RXD terminal (pin 53) of chip U5. One end of resistor R28 is connected to pin 12 of chip U6, and the other end is connected to button X17. One end of capacitor C30 is grounded, and the other end is connected to pin 16 of chip U6 and the 3.3V power supply. One end of capacitor C31 is grounded, and the other end is connected to pin 15 of chip U6 and the 3.3V power supply. Capacitor C6 can bypass high-frequency interference, improving chip stability.

[0035] The smart keyboard of this external barcode scanner can display transaction data and allow users to input transaction amounts via buttons. When paired with an existing barcode scanner box, it enables mobile payment collection and is easy to operate.

[0036] The matrix keyboard module is a 4x4 matrix keyboard, which uses 8 I / O ports to detect 16 keys.

[0037] The smart keyboard also includes a power amplifier module for outputting audio signals of transaction data sent by the main control module; the power amplifier module includes a digital signal to audio signal conversion circuit and an audio signal amplification circuit;

[0038] The digital signal to audio signal circuit is used to convert the digital signal transmitted by the main control module into an analog audio signal. The digital signal to audio signal circuit includes chip U8, resistor R36, capacitor C39, capacitor C40, capacitor C42 and capacitor C43.

[0039] The chip U8 is an ES7111 chip. One end of capacitor C39 is connected to pin 1 of chip U8 and the 3.3V power supply terminal, and the other end of capacitor C39 is grounded. One end of capacitor C42 is connected to pin 5 of chip U8, and the other end of capacitor C42 is grounded. One end of capacitor C43 is connected to pin 6 of chip U8 and the 3.3V power supply terminal, and the other end of capacitor C43 is grounded. One end of capacitor C40 is connected to pin 10 of chip U8 and the 3.3V power supply terminal, and the other end of capacitor C40 is grounded. One end of resistor R36 is grounded, and the other end is also grounded.

[0040] The U8 ES7111 communicates with the CAT1 module via the I2S protocol, converting audio data from digital signals (pins 2, 3, and 4) to differential audio signals (pins 7 and 8). Capacitors C39, C40, C42, and C43 activate filtering and bypassing to ensure stable chip operation. Resistor R36 separates the analog and digital grounds, achieving single-point grounding.

[0041] The audio signal amplification circuit is used to amplify analog audio signals. The audio signal amplification circuit includes chip U9, resistors R34, R35, and R37, capacitors C41, C44, C45, C46, ​​C47, and C48, and connector J5.

[0042] The chip U9 is a 4150C chip; pin 8 of the chip U8 is connected to one end of capacitor C41, the other end of capacitor C41 is connected to one end of resistor R34, and the other end of resistor R34 is connected to pin 3 of the chip U9; pin 7 of the chip U8 is connected to one end of capacitor C44, the other end of capacitor C44 is connected to one end of resistor R35, and the other end of resistor R35 is connected to pin 4 of the chip U9; one end of capacitor C45 is grounded and the other end is connected to pin 2 of the chip U9; The AUDIO_CS pin (pin 99 of chip U5) is connected to one end of resistor R37. The other end of resistor R37 is connected to one end of capacitor C46 and pin 1 of chip U9. The other end of capacitor C46 is grounded. Capacitors C47 and C48 are connected in parallel, with one end of this parallel circuit grounded and the other end connected to pin 6 of chip U9. Pin 1 of connector J5 is connected to pin 8 of chip U9, and pin 2 of connector J5 is connected to pin 5 of chip U9. Connector J5 is used to connect a speaker.

[0043] The differential inputs OUTP and OUTN operate within a specific frequency range through RC filter capacitors R34, C41, R35, and C44, and the volume is amplified and reduced through resistors R34 and R35. C45 is the bias capacitor for chip U9, and R37 and C46 form an RC delay circuit to turn chip U9 on and off. C47 is an energy storage filter to prevent voltage drops during chip operation that could cause malfunctions, and capacitor C48 is a bypass capacitor to reduce high-frequency signal interference to the chip.

[0044] The liquid crystal display module includes a backlight control circuit and a display connection circuit;

[0045] Backlight control circuit: LCD_CTL is a PWM signal, which controls the duty cycle to achieve high-speed switching of Q1, thereby controlling the LCD backlight. Resistors R48 and R49 are current-limiting resistors.

[0046] LCD module: Connects to the display module via FPC. Display content is transmitted via the LCD_SPI communication protocol.

[0047] The backlight control circuit includes resistors R46, R47, R48, and R49, transistor Q1, and connector J6. The LCD_CTL terminal (pin 78 of chip U5) is connected to one end of resistor R46. The other end of resistor R46 is connected to one end of resistor R47 and the base of transistor Q1. The other end of resistor R47 is grounded. The emitter of transistor Q1 is grounded. The collector of transistor Q1 is connected to pin 1 of connector J6. Resistors R48 and R49 are connected in parallel. One end of this parallel circuit is connected to the 3.3V power supply. The other end of resistor R49 is connected to pin 2 of connector J6. Connectors G2 and G1 of connector J6 are grounded. Connector J6 is used to connect the liquid crystal backlight device.

[0048] The display connection circuit includes a resistor R50, a capacitor C50, a capacitor C51, a capacitor C52, a capacitor C49, and a connector J7; one end of capacitor C52 is grounded and the other end is connected to pin 1 of connector J7; one end of capacitor C51 is connected to pin 2 of connector J7 and the other end is connected to pin 3 of connector J7; one end of capacitor C50 is connected to pin 4 of connector J7 and the other end is connected to pin 5 of connector J7; one end of capacitor C49 is grounded and the other end is connected to pin 7 of connector J7 and the 3.3V power supply terminal; one end of resistor R50 is connected to the 3.3V terminal and the other end is connected to pin 11 of connector J7.

[0049] C49 is an energy storage capacitor to reduce voltage fluctuations. R50 is a pull-up resistor to improve driving capability. C50, C51, and C52 are bias capacitors for the display module.

[0050] The smart keyboard also includes a WIFI module; the WIFI module includes a chip U7, resistors R29, R30, R31, R32, and R33, capacitors C36, C37, C38, C32, C33, C34, and C35, a crystal oscillator Y1, and an inductor L2.

[0051] Chip U7 is a YC1178 chip; the UART1_RXD terminal (pin 17 of chip U5) is connected to one end of resistor R29, and the other end of resistor R29 is connected to pin 6 of chip U7; the UART1_TXD terminal (pin 18 of chip U5) is connected to one end of resistor R30, and the other end of resistor R30 is connected to pin 7 of chip U7; the UART1_RTS terminal (pin 23 of chip U5) is connected to one end of resistor R31, and the other end of resistor R31 is connected to pin 8 of chip U7; the UART1_CTS terminal (pin 22 of chip U5) is connected to one end of resistor R32, and the other end of resistor R32 is connected to pin 9 of chip U7; one end of resistor R33 is grounded and the other end is connected to pin 11 of chip U7; these four resistors reduce crosstalk during UART communication and improve transmission stability; one end of capacitor C36 is grounded and the other end is connected to pin 14 of chip U7, providing... Internal power supply bypass capacitors reduce external high-frequency interference; one end of capacitor C37 is grounded and the other end is connected to pin 15 of chip U7 and pin 1 of crystal oscillator Y1 respectively; pins 2 and 4 of crystal oscillator Y1 are grounded and pin 3 is connected to pin 16 of chip U7 and capacitor C38 respectively, and the other end of capacitor C38 is grounded. The crystal oscillator serves as a reference clock for the chip, and the chip operates according to this clock; one end of capacitor C32 is grounded and the other end is connected to pin 21 of chip U7; one end of capacitor C33 is grounded and the other end is connected to pins 19 and 20 of chip U7 and the 3.3V power supply terminal. Capacitors C32 and C33 provide internal power supply bypass capacitors to reduce external high-frequency interference; one end of capacitor C34 is grounded and the other end is connected to pin 18 of U7 and one end of inductor L2 respectively; one end of capacitor C35 is grounded and the other end is connected to the other end of inductor L2, forming a Π-shaped matching circuit to improve network transmission stability.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of this application, and are not intended to limit them; although the embodiments of this application have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A smart keyboard with an external code scanner, characterized in that: The system includes a main control module and an auxiliary control module, a matrix keyboard module, and an LCD display module connected to the main control module. The auxiliary control module is used for data transmission with the barcode scanner and for acquiring and transmitting transaction data back to the main control module. The matrix keyboard module is used for key input, and the main control module transmits the key input from the matrix keyboard module to the barcode scanner through the auxiliary control module. The LCD display module is used to display the key input and transaction data sent by the main control module. The main control module includes a chip U5 and a bypass circuit. The chip U5 is an AIR780EP chip. The bypass circuit includes capacitors C18, C19, C20 and C21 connected in parallel. One end of the parallel circuit is grounded and the other end is connected to pins 42 and 43 of U5 respectively. The auxiliary control module includes chip U6, resistors R26, R27, and R28, capacitors C30 and C31, and button X17. The chip U6 is a CH554G chip. The chip U6 is connected to the barcode scanner via USB, and the chip U6 communicates with the chip U5 via a serial port. One end of the resistor R26 is connected to pin 4 of the chip U6, and the other end is connected to the UART3_TXD terminal of the chip U5. One end of the resistor R27 is connected to pin 5 of the chip U6, and the other end is connected to the UART3_RXD terminal of the chip U5. One end of the resistor R28 is connected to pin 12 of the chip U6, and the other end is connected to button X17. One end of the capacitor C30 is grounded, and the other end is connected to pin 16 of the chip U6 and the 3.3V power supply terminal. One end of the capacitor C31 is grounded, and the other end is connected to pin 15 of the chip U6 and the 3.3V power supply terminal.

2. The smart keyboard with external code scanner according to claim 1, characterized in that: The matrix keyboard module is a 4x4 matrix keyboard, which uses 8 I / O ports to detect 16 keys.

3. The smart keyboard for an external barcode scanner according to claim 1, characterized in that: The smart keyboard also includes a power amplifier module for outputting audio signals of transaction data sent by the main control module; the power amplifier module includes a digital signal to audio signal conversion circuit and an audio signal amplification circuit; The digital signal to audio signal circuit is used to convert the digital signal transmitted by the main control module into an analog audio signal. The digital signal to audio signal circuit includes chip U8, resistor R36, capacitor C39, capacitor C40, capacitor C42 and capacitor C43. The chip U8 is an ES7111 chip. One end of capacitor C39 is connected to pin 1 of chip U8 and the 3.3V power supply terminal, and the other end of capacitor C39 is grounded. One end of capacitor C42 is connected to pin 5 of chip U8, and the other end of capacitor C42 is grounded. One end of capacitor C43 is connected to pin 6 of chip U8 and the 3.3V power supply terminal, and the other end of capacitor C43 is grounded. One end of capacitor C40 is connected to pin 10 of chip U8 and the 3.3V power supply terminal, and the other end of capacitor C40 is grounded. One end of resistor R36 is grounded, and the other end is also grounded. The audio signal amplification circuit is used to amplify analog audio signals. The audio signal amplification circuit includes chip U9, resistors R34, R35, and R37, capacitors C41, C44, C45, C46, ​​C47, and C48, and connector J5. The chip U9 is a 4150C chip; pin 8 of the chip U8 is connected to one end of capacitor C41, the other end of capacitor C41 is connected to one end of resistor R34, and the other end of resistor R34 is connected to pin 3 of the chip U9; pin 7 of the chip U8 is connected to one end of capacitor C44, the other end of capacitor C44 is connected to one end of resistor R35, and the other end of resistor R35 is connected to pin 4 of the chip U9; one end of capacitor C45 is grounded and the other end is connected to pin 2 of the chip U9; The AUDIO_CS terminal is connected to one end of resistor R37. The other end of resistor R37 is connected to one end of capacitor C46 and pin 1 of chip U9. The other end of capacitor C46 is grounded. Capacitors C47 and C48 are connected in parallel. One end of this parallel circuit is grounded and the other end is connected to pin 6 of chip U9. Pin 1 of connector J5 is connected to pin 8 of chip U9. Pin 2 of connector J5 is connected to pin 5 of chip U9.

4. The smart keyboard for an external barcode scanner according to claim 1, characterized in that: The liquid crystal display module includes a backlight control circuit and a display connection circuit; The backlight control circuit includes resistors R46, R47, R48, and R49, transistor Q1, and connector J6. The LCD_CTL terminal is connected to one end of resistor R46. The other end of resistor R46 is connected to one end of resistor R47 and the base of transistor Q1. The other end of resistor R47 is grounded. The emitter of transistor Q1 is grounded. The collector of transistor Q1 is connected to pin 1 of connector J6. Resistors R48 and R49 are connected in parallel. One end of this parallel circuit is connected to the 3.3V power supply. The other end of resistor R49 is connected to pin 2 of connector J6. Connectors G2 and G1 of connector J6 are grounded. The display connection circuit includes a resistor R50, a capacitor C50, a capacitor C51, a capacitor C52, a capacitor C49, and a connector J7; one end of capacitor C52 is grounded and the other end is connected to pin 1 of connector J7; one end of capacitor C51 is connected to pin 2 of connector J7 and the other end is connected to pin 3 of connector J7; one end of capacitor C50 is connected to pin 4 of connector J7 and the other end is connected to pin 5 of connector J7; one end of capacitor C49 is grounded and the other end is connected to pin 7 of connector J7 and the 3.3V power supply terminal; one end of resistor R50 is connected to the 3.3V terminal and the other end is connected to pin 11 of connector J7.

5. The smart keyboard for an external barcode scanner according to claim 1, characterized in that: The smart keyboard also includes a WIFI module; the WIFI module includes a chip U7, resistors R29, R30, R31, R32, and R33, capacitors C36, C37, C38, C32, C33, C34, and C35, a crystal oscillator Y1, and an inductor L2. The chip U7 is a YC1178 chip; the UART1_RXD terminal is connected to one end of resistor R29, and the other end of resistor R29 is connected to pin 6 of chip U7; the UART1_TXD terminal is connected to one end of resistor R30, and the other end of resistor R30 is connected to pin 7 of chip U7. The UART1_RTS terminal is connected to one end of resistor R31, and the other end of resistor R31 is connected to pin 8 of chip U7; The UART1_CTS terminal is connected to one end of resistor R32, and the other end of resistor R32 is connected to pin 9 of chip U7; one end of resistor R33 is grounded and the other end is connected to pin 11 of chip U7; one end of capacitor C36 is grounded and the other end is connected to pin 14 of chip U7; one end of capacitor C37 is grounded and the other end is connected to pin 15 of chip U7 and pin 1 of crystal oscillator Y1 respectively. Crystal oscillator Y1 has pins 2 and 4 grounded, and pin 3 connected to pin 16 of chip U7 and capacitor C38 respectively. The other end of capacitor C38 is grounded. One end of capacitor C32 is grounded and the other end is connected to pin 21 of chip U7. One end of capacitor C33 is grounded and the other end is connected to pins 19 and 20 of chip U7 and the 3.3V power supply. One end of capacitor C34 is grounded and the other end is connected to pin 18 of U7 and one end of inductor L2 respectively; one end of capacitor C35 is grounded and the other end is connected to the other end of inductor L2.

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