A serial port reading circuit for tax reporting on fuel dispensers

Abstract

This application provides a serial port reading circuit for fuel dispenser tax reporting, comprising: a conversion chip, a data transmission circuit, a decryption card, and a CPU chip. The input terminal of the conversion chip is electrically connected to the fuel dispenser's tax reporting serial port via a data reading interface. The output terminal of the conversion chip is electrically connected to the first input terminal of the CPU chip via the data transmission circuit to transmit the read fuel data to the CPU chip. The second output terminal of the CPU chip is electrically connected to the input terminal of the decryption card, and the output terminal of the decryption card is electrically connected to the second input terminal of the CPU chip. The first output terminal of the CPU chip is electrically connected to an upload chip via the data transmission circuit to send the decrypted fuel data to the tax system via the upload chip. This application allows direct reading of fuel dispenser data via a data reading interface that connects directly to the fuel dispenser's tax reporting serial port, eliminating the need for manual data collection using a handheld fuel dispenser data collector and effectively improving the efficiency of fuel dispenser data reading.

Description

Technical Field

[0001] This utility model belongs to the field of data reading technology, specifically, it relates to a serial port reading circuit for tax reporting on a fuel dispenser. Background Technology

[0002] Fuel dispensers (referred to as fuel dispensers) are mainly used to refuel vehicles and dynamically measure the cumulative flow of fuel. The refueling data from these dispensers (including the amount dispensed in a given transaction, daily cumulative amount, monthly cumulative amount, annual cumulative amount, and total cumulative amount) needs to be periodically uploaded to the tax authorities' data center for tax reporting. Currently, tax reporting is done manually by using a handheld device (fuel data collector) to read the fuel data on-site through the fuel dispenser's serial port. Specifically, the data collector's interface is connected to the fuel dispenser's serial port to read the fuel data, which is then connected to the tax system, and the data is manually uploaded. This method of reading fuel data is inefficient, resulting in low efficiency for fuel dispenser tax reporting.

[0003] Therefore, this application provides a serial port reading circuit for fuel dispenser tax reporting, which can directly read the fuel dispensing data of the fuel dispenser and upload the fuel dispensing data to the tax system, which can effectively improve the reading efficiency of fuel dispensing data of the fuel dispenser. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a fuel dispenser tax declaration serial port reading circuit, including: a conversion chip, a data transmission circuit, a decryption card and a CPU chip;

[0005] The input terminal of the conversion chip is suitable for electrical connection with the tax payment serial port of the fuel dispenser through the data reading interface, and the output terminal of the conversion chip is electrically connected to the first input terminal of the CPU chip through the data transmission circuit to transmit the read fuel data to the CPU chip.

[0006] The second output terminal of the CPU chip is electrically connected to the input terminal of the decryption card, and the output terminal of the decryption card is electrically connected to the second input terminal of the CPU chip. The first output terminal of the CPU chip is suitable for being electrically connected to the upload chip through the data transmission circuit, so as to send the decrypted refueling data to the tax system through the upload chip.

[0007] In one possible implementation, the data reading interface includes two first pin connectors adapted to read refueling data from the tax reporting serial ports of two fuel dispensers, respectively.

[0008] One possible implementation also includes a pull-up resistor circuit;

[0009] The pull-up resistor circuit is electrically connected to the decryption card and the data transmission circuit respectively, and is suitable for providing a continuous high level to the decryption card.

[0010] In one possible implementation, the data transmission circuitry includes a second pin connector;

[0011] The first input terminal of the second pin connector is electrically connected to the output terminal of the conversion chip, the first output terminal of the second pin connector is electrically connected to the first input terminal of the CPU chip and the upload chip, and the second input terminal of the second pin connector is electrically connected to the first output terminal of the CPU chip.

[0012] One possible implementation also includes: an indicator light circuit; the indicator light circuit is electrically connected to the CPU chip.

[0013] One possible implementation also includes: a filter circuit; the filter circuit is electrically connected to the CPU chip.

[0014] In one possible implementation, the CPU chip is a GD32 model chip.

[0015] In one possible implementation, the conversion chip is the SP3232EE model.

[0016] Beneficial Effects: The conversion chip of this application connects directly to the tax reporting serial port of the fuel dispenser via a data reading interface, enabling direct reading of fuel dispensing data. This eliminates the need for manual data collection using a handheld fuel dispenser data acquisition device, significantly improving data reading efficiency. Furthermore, the conversion chip transmits the read fuel dispensing data to a CPU chip via a data transmission circuit. The CPU chip then transmits the data to a decryption card for decryption, obtaining the decrypted data. The decryption card sends the decrypted data back to the CPU chip, which then transmits it to an upload chip via the data transmission circuit. The upload chip directly sends the decrypted data to the tax system. In short, the entire process utilizes the fuel dispenser tax reporting serial port reading circuit of this application to directly read fuel dispensing data, eliminating the need for manual data collection using a handheld device (fuel dispenser data acquisition device), thus significantly improving data reading efficiency. Simultaneously, the CPU chip of this application can also directly upload the read fuel dispensing data to the tax system via the upload chip connected to the data transmission circuit, eliminating the need for manual uploading of fuel dispensing data read by a handheld device, further improving the efficiency of fuel dispenser tax reporting.

[0017] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings. Attached Figure Description

[0018] The accompanying drawings described below are merely some embodiments. Those skilled in the art can obtain other drawings based on these drawings without any creative effort. In the drawings:

[0019] Figure 1 This is a schematic diagram of a serial port reading circuit for tax reporting on a fuel dispenser according to an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of a first pin connector according to an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of a conversion chip according to an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the second pin connector according to an embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of a CPU chip according to an embodiment of the present invention;

[0024] Figure 6 This is a schematic diagram of a decryption card according to an embodiment of the present invention;

[0025] Figure 7 This is a schematic diagram of a pull-up resistor circuit according to an embodiment of the present invention;

[0026] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the present invention in any way, but rather to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0027] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0028] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application or to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0030] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0031] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0032] Figure 1 This application illustrates a serial port reading circuit for tax reporting on a fuel dispenser. See [link / reference]. Figure 1 As shown, the reading circuit includes a conversion chip U2, a data transmission circuit, a decryption card P3, and a CPU chip U1. The input terminal of the conversion chip U2 is electrically connected to the fuel dispenser's tax reporting serial port through a data reading interface. The output terminal of the conversion chip U2 is electrically connected to the first input terminal of the CPU chip U1 through the data transmission circuit to transmit the read fuel data to the CPU chip U1. The second output terminal of the CPU chip U1 is electrically connected to the input terminal of the decryption card P3, and the output terminal of the decryption card P3 is electrically connected to the second input terminal of the CPU chip U1. The first output terminal of the CPU chip U1 is electrically connected to the upload chip through the data transmission circuit to send the decrypted fuel data to the tax system via the upload chip.

[0033] The conversion chip U2 of this application connects directly to the tax reporting serial port of the fuel dispenser via a data reading interface, allowing it to directly read the fuel dispensing data. This eliminates the need for manual data collection using a handheld fuel dispenser data acquisition device, effectively improving the efficiency of fuel data reading. Furthermore, the conversion chip U2 transmits the read fuel dispensing data to the CPU chip U1 via a data transmission circuit. The CPU chip U1 then transmits the data to the decryption card P3 for decryption, obtaining the decrypted fuel dispensing data. The decryption card P3 sends the decrypted data back to the CPU chip U1. Finally, the CPU chip U1 transmits the fuel dispensing data to the upload chip via the data transmission circuit. The upload chip directly sends the decrypted fuel dispensing data to the tax system. In other words, the CPU chip U1 can also directly upload the read fuel dispensing data to the tax system via the upload chip connected to the data transmission circuit, eliminating the need for manual uploading of fuel dispensing data read by a handheld device and further improving the efficiency of fuel dispenser tax reporting.

[0034] In one possible implementation, see Figure 1 and Figure 2 As shown, the data reading interface includes two first pin connectors ( Figure 2 P4 and P5 are used to read refueling data from the tax reporting serial ports of two fuel dispensers respectively.

[0035] In one possible implementation, the conversion chip U2 uses the SP3232EE model chip, which can connect to two first pin connectors simultaneously to read refueling data from two fuel dispensers at the same time.

[0036] In one possible implementation, see [link to relevant documentation] Figures 1 to 3As shown, the first connector P4 is connected to the tax reporting serial port of a fuel dispenser, and pin 1 (CPT terminal) of the first connector P4 is electrically connected to pin 13 (R1IN terminal) of the conversion chip U2, and pin 2 (CPR terminal) of the first connector P4 is electrically connected to pin 14 (T1OUT terminal) of the conversion chip U2, so that the conversion chip U2 can communicate bidirectionally with a fuel dispenser through the first connector P4. That is, after the first connector P4 reads the fueling data through the fuel dispenser's serial port, it transmits it to the conversion chip U2 through the circuit connected to pin 1 (CPT terminal) of the first connector P4 and pin 13 (R1IN terminal) of the conversion chip U2. The conversion chip U2 converts the read digital fueling data into electrical fueling data and outputs it through pin 12 (R1OUT terminal). Meanwhile, after receiving the tax declaration result electrical signal through pin 11 (T1IN terminal) of the conversion chip U2, the conversion chip U2 converts the electrical signal tax declaration result into a digital signal tax declaration result, which is then transmitted out through pin 14 (T1OUT terminal). The converted digital signal tax declaration result is received through pin 2 (CPR terminal) of the first pin connector P4. The first pin connector P4 transmits the result to the fuel dispenser through the fuel dispenser's tax declaration serial port for display.

[0037] The first connector P5 is connected to the serial port of another fuel dispenser. Pin 1 (JYT) of the first connector P5 is electrically connected to pin 8 (R2IN) of the conversion chip U2, and pin 2 (JYR) of the first connector P5 is electrically connected to pin 14 (T2OUT) of the conversion chip U2. This allows the conversion chip U2 to communicate bidirectionally with the other fuel dispenser via the first connector P5. Specifically, after reading the fuel dispensing data through the fuel dispenser's serial port, the first connector P5 transmits the data to the conversion chip U2 through the circuit connecting pin 1 (JYT) of the first connector P5 and pin 8 (R2IN) of the conversion chip U2. The conversion chip U2 converts the read digital fuel dispensing data into electrical fuel dispensing data, which is then output from pin 14 (R2OUT). Simultaneously, after receiving the tax declaration result electrical signal through pin 10 (T2IN terminal) of the conversion chip U2, the conversion chip U2 converts the electrical signal into a digital signal and outputs it through pin 7 (T2OUT terminal). The converted digital signal is then received through pin 2 (JYR terminal) of the first connector P5. The first connector P5 transmits the data to the fuel dispenser via its serial port for display. Thus, the conversion chip U2 can simultaneously read the refueling data from two fuel dispensers and communicate bidirectionally with both dispensers simultaneously.

[0038] It should also be noted that, see Figure 3As shown, the converter chip U2 is also connected to protective capacitors, namely, capacitor C6, capacitor C7, capacitor C8, capacitor C9, and capacitor C10, which are suitable for providing a stable working environment. The positive terminal of capacitor C6 is electrically connected to both the external power supply and pin 16 (VCC terminal) of converter chip U2, and the negative terminal of capacitor C6 is grounded; capacitor C7 is located between pin 1 (C1+ terminal) and pin 3 (C1- terminal) of converter chip U2; capacitor C8 is located between pin 4 (C2+ terminal) and pin 5 (C2- terminal) of converter chip U2; capacitor C9 is located between pin 6 (V- terminal) and pin 15 (GND terminal) of converter chip U2; and capacitor C10 is located between pin 2 (V+ terminal) and pin 15 (GND terminal) of converter chip U2. Furthermore, capacitors C9 and C10 are connected in parallel to ground.

[0039] In one possible implementation, the conversion chip U2 is electrically connected to the first input terminal of the CPU chip U1 via a data transmission circuit to transmit the converted refueling data to the CPU chip U1. In another possible implementation, the CPU chip U1 is a GD32 model chip.

[0040] In one possible implementation, the data transmission circuit includes a second connector P1, through which the conversion chip U2 is electrically connected to the CPU chip U1. Specifically, the first input terminal of the second connector P1 is electrically connected to the output terminal of the conversion chip U2. Specifically, pin 2 (RXD1) of the second connector P1 is electrically connected to pin 12 (R1OUT) of the conversion chip U2, and pin 8 (RXD2) of the second connector P1 is electrically connected to pin 9 (R2OUT) of the conversion chip U2. Simultaneously, pin 1 (TXD1) of the second connector P1 is electrically connected to pin 11 (T1IN) of the conversion chip U2, and pin 7 (TXD2) of the second connector P1 is electrically connected to pin 10 (T2IN) of the conversion chip U2, thus achieving bidirectional connection between the conversion chip U2 and the first connector P1. At this time, the refueling data acquired by the conversion chip U2 is transmitted to the second connector P1.

[0041] The first output terminal of the second connector P1, namely pin 9 (RXD3), is electrically connected to the first input terminal of the CPU chip U1, namely pin 26 (PA3). The second input terminal of the second connector P1, namely pin 10 (TXD3), is electrically connected to the output terminal of the CPU chip U1, namely pin 25 (PA2), to achieve a bidirectional connection between the CPU chip U1 and the second connector P1. That is, the second connector P1 transmits the read refueling data through pin 9 (RXD3), and the CPU chip U1 receives the refueling data from the two fuel dispensers through pin 26 (PA3).

[0042] In one possible implementation, the second output terminal of the CPU chip U1 is also electrically connected to the input terminal of the decryption card P3, and the output terminal of the decryption card P3 is electrically connected to the second input terminal of the CPU chip U1.

[0043] Further, see Figure 1 and Figure 4 As shown, pin 2 (RXD1) of the second connector P1 is the first input terminal of the second connector P1, pin 10 (TXD3) of the second connector P1 is the second input terminal of the second connector P1, and pin 9 (RXD3) of the second connector P1 is the first output terminal of the second connector P1. Pin 26 (PA3) of the CPU chip U1 is the first input terminal of the CPU chip U1, pin 25 (PA2) of the CPU chip U1 is the first output terminal of the CPU chip U1, and pin 68 (PA9) of the CPU chip U1 is the second input and second output terminal of the CPU chip.

[0044] In one possible implementation, the decryption card P3 uses a decryption card model that conforms to the 7816-3 dedicated CPU card model.

[0045] In one possible implementation, pin 33 (PC4) of CPU chip U1 is electrically connected to pin 10 (Card_Switch) of decryption card P3. Pin 54 (PB15) of CPU chip U1 is electrically connected to pin 1 (Card_PWR) of decryption card P3. Pin 67 (PA8) of CPU chip U1 is electrically connected to pin 3 (Card_CLK) of decryption card P3. Pin 68 (PA9) of CPU chip U1 is electrically connected to pin 7 (Card_DAT) of decryption card P3. Pin 71 (PA12) of CPU chip U1 is electrically connected to pin 2 (Card_RST) of decryption card P3. The refueling data obtained by CPU chip U1 is output through pin 68 (PA9), and received by decryption card P3 through pin 7 (Card_DAT). Decryption card P3 decrypts the refueling data to obtain the decrypted refueling data, which is then transmitted back to CPU chip U1. That is, pin 7 (Card_DAT terminal) of decryption card P3 is electrically connected to pin 68 (PA9 terminal) of CPU chip U1. The decrypted refueling data is directly transmitted to CPU chip U1 via the circuit connecting pin 7 (Card_DAT terminal) of decryption card P3 and pin 68 (PA9 terminal) of CPU chip U1. At this time, CPU chip U1 receives the decrypted refueling data. See [link to relevant documentation] for details. Figure 6 As shown, pin 7 (Card_DAT terminal) of decryption card P3 serves as both the input and output terminal of decryption card P3.

[0046] In one possible implementation, the first output terminal of the second connector P1, namely pin 9 (RXD3), is also electrically connected to the upload chip. Specifically, the CPU chip U1 transmits the decrypted refueling data to the second connector P1 via a circuit connected to pin 10 (TXD3) of the second connector P1 through pin 25 (PA2). The second connector P1 then transmits the decrypted refueling data to the upload chip via pin 9 (RXD3), and the upload chip uploads the decrypted refueling data to the tax system.

[0047] In one possible implementation, the decryption card P3 is also connected to a sixth resistor R9. See also Figure 1 and Figure 6 As shown, the sixth resistor R9 is positioned between pin 1 (Card_PWR terminal) and pin 7 (Card_DAT terminal) of the decryption card P3. It should be noted that the sixth resistor R9 is preferably a 10KΩ resistor.

[0048] In one possible implementation, see [link to relevant documentation] Figure 7As shown, it also includes a pull-up resistor circuit, which is electrically connected to the decryption card P3 and the data transmission circuit. This circuit provides a continuous high level to the decryption card P3 to amplify the decrypted refueling data signal. The pull-up resistor circuit includes five resistors: R5, R6, R7, R8, and R10. These resistors are connected in parallel.

[0049] In one possible implementation, one end of the first resistor R5, the second resistor R6, the third resistor R7, the fourth resistor R8, and the fifth resistor R10 are all connected to an external power supply. The other end of the first resistor R5 is electrically connected to pin 4 (REV1) of the second pin connector P1. The other end of the second resistor R6 is electrically connected to pin 5 (REV2) of the second pin connector P1. The other end of the third resistor R7 is electrically connected to pin 12 (REV3) of the second pin connector P1. The other end of the fourth resistor R8 is electrically connected to pin 13 (REV4) of the second pin connector P1. The other end of the fifth resistor R10 is electrically connected to pin 10 (Card_Switch) of the decryption card P3.

[0050] Furthermore, the CPU chip U1 also includes a twelfth capacitor C11 and a thirteenth capacitor C12. The negative terminals of the twelfth capacitor C11 and the thirteenth capacitor C12 are simultaneously connected to ground at pins 19 (VSSA terminal) and 20 (VREF- terminal) of the CPU chip U1, while their positive terminals are connected to the power supply and pins 21 (VREF+ terminal) and 22 (VDDA terminal) of the CPU chip U1. The twelfth capacitor C11 and the thirteenth capacitor C12 are connected in parallel. Preferably, the twelfth capacitor C11 is a 1μF capacitor and the thirteenth capacitor C12 is a 0.01μF capacitor.

[0051] It should also be noted that terminal 14 (NRST) of CPU chip U1 is connected to the external power supply after being connected to the seventh resistor R1. Simultaneously, terminal 14 (NRST) of CPU chip U1 is grounded after being connected to the fourteenth capacitor C13, and the seventh resistor R1 and the fourteenth capacitor C13 are connected in parallel. Terminal 94 (BOOT0) of CPU chip U1 is grounded after being connected to the eighth resistor R2. Preferably, both the seventh and eighth resistors R2 are 10KΩ resistors, and the fourteenth capacitor C13 is preferably a 0.1μF capacitor.

[0052] In one possible implementation, see [link to relevant documentation] Figure 1As shown, it also includes an indicator light circuit, which is electrically connected to the CPU chip U1. Specifically, the indicator light circuit includes a ninth resistor R3, a tenth resistor R4, and light-emitting diodes D1 and D2. Terminal 83 (PD2) of the CPU chip U1 is connected to the light-emitting diode D1 and the ninth resistor R3 in sequence and then connected to an external power supply. The external power supply is connected to the tenth resistor R4 and the light-emitting diode D2 in sequence and then grounded.

[0053] In one possible implementation, see [link to relevant documentation] Figure 1 As shown, it also includes a debug interface P2, which is electrically connected to the CPU chip U1. Specifically, pin 3 (SW CLK terminal) of debug interface P2 is electrically connected to pin 76 (PA14 terminal) of CPU chip U1, pin 4 (SW DIO terminal) of debug interface P2 is electrically connected to pin 72 (PA13 terminal) of CPU chip U1, and pin 5 (RST terminal) of debug interface P2 is electrically connected to pin 14 (NRST terminal) of CPU chip U1.

[0054] In one possible implementation, a filtering circuit is also included, which is electrically connected to the CPU chip U1. See [link / reference] Figure 5 As shown, the filter circuit contains five non-polarized capacitors and one polarized capacitor. See [link to relevant documentation]. Figure 5 As shown, the five non-polarized capacitors are the sixth capacitor C1, the seventh capacitor C2, the eighth capacitor C3, the ninth capacitor C4, and the tenth capacitor C5. The one polarized capacitor is the eleventh capacitor E1. The sixth capacitor C1, the seventh capacitor C2, the eighth capacitor C3, the ninth capacitor C4, the tenth capacitor C5, and the eleventh capacitor E1 are connected in parallel, with their positive terminals all connected to the external power supply and their negative terminals all grounded. It should be noted that the non-polarized capacitors are preferably 0.1μF capacitors, the polarized capacitors are preferably 4.7μF capacitors, and the input voltage is preferably 16V.

[0055] It should be noted that the VCC pins in this application are all connected to an external power supply, and the GND pins are all grounded.

[0056] In one possible implementation, the time interval for the CPU chip U1 to read refueling data can be set. Specifically, the time interval must be greater than 10 seconds, but the exact time interval is not limited.

[0057] In one possible implementation, the fuel dispenser tax reporting serial port reading circuit of this application is installed inside the mainboard housing of the fuel dispenser, and the components in the circuit are small in size and easy to install.

[0058] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A serial port reading circuit for tax reporting on a fuel dispenser, characterized in that, include: Conversion chip, data transmission circuit, decryption card, and CPU chip; The input terminal of the conversion chip is suitable for electrical connection with the tax reporting serial port of the fuel dispenser through the data reading interface, and the output terminal of the conversion chip is electrically connected to the first input terminal of the CPU chip through the data transmission circuit to transmit the read fueling data to the CPU chip. The second output terminal of the CPU chip is electrically connected to the input terminal of the decryption card, and the output terminal of the decryption card is electrically connected to the second input terminal of the CPU chip. The first output terminal of the CPU chip is adapted to be electrically connected to the upload chip through the data transmission circuit so as to send the decrypted refueling data to the tax system through the upload chip.

2. The serial port reading circuit for tax reporting on a fuel dispenser according to claim 1, characterized in that, The data reading interface includes two first pin connectors, which are suitable for reading refueling data from the tax reporting serial ports of two fuel dispensers respectively.

3. The serial port reading circuit for tax reporting on a fuel dispenser according to claim 1, characterized in that, It also includes pull-up resistor circuitry; The pull-up resistor circuit is electrically connected to the decryption card and the data transmission circuit respectively, and is suitable for providing a continuous high level to the decryption card.

4. The serial port reading circuit for tax reporting on a fuel dispenser according to claim 1, characterized in that, The data transmission circuit includes a second pin connector; The first input terminal of the second pin connector is electrically connected to the output terminal of the conversion chip, the first output terminal of the second pin connector is electrically connected to the first input terminal of the CPU chip and the upload chip, and the second input terminal of the second pin connector is electrically connected to the first output terminal of the CPU chip.

5. The serial port reading circuit for tax reporting on a fuel dispenser according to claim 1, characterized in that, Also includes: Indicator light circuit; The indicator light circuit is electrically connected to the CPU chip.

6. The serial port reading circuit for tax reporting on a fuel dispenser according to claim 1, characterized in that, Also includes: Filtering circuit; The filter circuit is electrically connected to the CPU chip.

7. The serial port reading circuit for tax reporting on a fuel dispenser according to claim 1, characterized in that, The CPU chip used is the GD32 model.

8. The serial port reading circuit for tax reporting on a fuel dispenser according to claim 1, characterized in that, The conversion chip used is the SP3232EE model.

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