A test device for detecting performance of a vehicle CAN serial port and a LIN serial port

Abstract

The application discloses a kind of test devices for detecting vehicle CAN serial port and LIN serial port performance, including main control circuit, detection signal input circuit, CAN signal identification circuit, LIN signal identification circuit, display circuit and power supply circuit;With CAN signal detection mode and LIN signal detection mode;Main control circuit drives CAN signal identification circuit or LIN signal identification circuit according to the signal collected by detection signal input circuit to carry out operation processing, and outputs CAN signal identification data information or LIN signal identification data information through display circuit;Power supply circuit provides electric energy;It can directly detect the data communication transmission effect of vehicle circuit electric appliance module, without connecting any PC end software or connecting oscilloscope, the professional ability requirement of operator is low, convenient to operate, simple and compact structure, small volume, light weight, easy to carry.

Description

Technical Field

[0001] This invention belongs to the technical field of vehicle digital information transmission equipment, specifically relating to a testing device for detecting the performance of vehicle CAN serial ports and LIN serial ports. Background Technology

[0002] During the repair of vehicle circuit electrical modules, it is common to encounter situations where the communication line voltage is normal, but data communication cannot be achieved. Traditional testing methods require configuring a dedicated CAN / LIN analyzer and connecting it to PC software or an oscilloscope to perform signal testing to confirm whether communication data can be effectively transmitted before proceeding to the next step of troubleshooting. The testing and troubleshooting process requires operators to have a high level of professional skills, involves a large number of testing and repair equipment, occupies a large space, and is cumbersome to connect, arrange, operate, and move. Summary of the Invention

[0003] To address the aforementioned problems in the existing technology, the present invention aims to provide a testing device for detecting the performance of a vehicle's CAN serial port and LIN serial port. This device can directly detect the data communication transmission effect of the vehicle's electrical circuit modules, requires minimal professional skills from operators, and is easy to operate.

[0004] The technical solution adopted in this invention is as follows:

[0005] A testing device for detecting the performance of a vehicle's CAN serial port and LIN serial port includes a main control circuit, a detection signal input circuit, a CAN signal recognition circuit, a LIN signal recognition circuit, a display circuit, and a power supply circuit; the detection signal input circuit, CAN signal recognition circuit, LIN signal recognition circuit, display circuit, and power supply circuit are all connected to the main control circuit.

[0006] The testing device for detecting the performance of the vehicle's CAN serial port and LIN serial port has a CAN signal detection working mode and a LIN signal detection working mode.

[0007] The main control circuit is used to drive the CAN signal recognition circuit or the LIN signal recognition circuit to perform calculations based on the signals collected by the detection signal input circuit, and outputs CAN signal recognition data information or LIN signal recognition data information through the display circuit; the CAN signal recognition data information includes at least CAN high level, CAN low level and CAN bus baud rate; the LIN signal recognition data information includes at least LIN bus baud rate.

[0008] The power supply circuit is used to provide electrical energy.

[0009] Furthermore, the power supply circuit is equipped with a power button switch, which is also used to switch between CAN signal detection mode and LIN signal detection mode.

[0010] Furthermore, the main control circuit includes a main control chip U3, which is an industrial-grade general-purpose 32-bit microcontroller.

[0011] Furthermore, the detection signal input circuit includes a first relay K1 and a second relay K2;

[0012] The first relay K1 is used to switch to CAN high-level mode or CAN low-level mode when the CAN signal detection working mode is activated.

[0013] The second relay K2 is used to switch between CAN signal detection mode and LIN signal detection mode.

[0014] Furthermore, the detection signal input circuit also includes an eighth diode D8, a ninth diode D9, a fifth field-effect transistor Q5, and a sixth field-effect transistor Q6;

[0015] The fifth field-effect transistor Q5 and the eighth diode D8 are used to control the operating mode of the first relay K1;

[0016] The sixth field-effect transistor Q6 and the ninth diode D9 are used to control the operating mode of the second relay K2.

[0017] Furthermore, the CAN signal identification circuit includes a CAN bus transceiver chip U2, the transmitter data input terminal TXD of the CAN bus transceiver chip U2 is connected to the PB9 control port of the main control chip U3, and the receiver data output terminal RXD is connected to the PB8 control port of the main control chip U3.

[0018] The low-potential CAN voltage input / output terminal CANL of the CAN bus transceiver chip U2 is connected to the NC1 port of the second relay K2 in the detection signal input circuit, and the high-potential CAN voltage input / output terminal CANH is connected to the NC2 port of the second relay K2 in the detection signal input circuit.

[0019] Furthermore, a protection circuit is provided between the CAN voltage input / output terminal CANL and the high-potential CAN voltage input / output terminal CANH of the CAN bus transceiver chip U2. The protection circuit is connected to the PA1 control port and PB0 control port of the main control chip U3.

[0020] Furthermore, the LIN signal identification circuit includes a LIN transceiver U6, whose LIN bus input / output port is connected to the NO2 port of the second relay K2;

[0021] The RXD receiver data output port of the LIN transceiver U6 is connected to the PA10 control port of the main control chip U3, the TXD transmitter data input port is connected to the PA9 control port of the main control chip U3, and the SLP_N enable input port is connected to the PA15 control port of the main control chip U3.

[0022] The LIN bus input / output ports of the LIN transceiver U6 are also connected to the PB13 control port and PB1 control port of the main control chip U3 through a voltage detection circuit.

[0023] Furthermore, the display circuit is connected to the PB15 control port, PB14 control port, PB12 control port, PA5 control port and PA6 control port of the main control chip U3.

[0024] Finally, the power supply circuit includes a three-terminal positive voltage regulator U1, a linear regulator U5, and a boost inverter U7. The boost inverter U7 is used to provide VCC-12V voltage, the three-terminal positive voltage regulator U1 is used to provide VCC-5V voltage, and the linear regulator U5 is used to provide VCC-3V3 voltage.

[0025] The beneficial effects of this invention are as follows:

[0026] A testing device for detecting the performance of a vehicle's CAN and LIN serial ports includes a main control circuit, a detection signal input circuit, a CAN signal recognition circuit, a LIN signal recognition circuit, a display circuit, and a power supply circuit. It features both CAN and LIN signal detection modes. The main control circuit drives the CAN or LIN signal recognition circuit to perform calculations based on signals acquired by the detection signal input circuit, and outputs CAN or LIN signal recognition data information through the display circuit. The power supply circuit provides electrical energy. It can directly test the data communication transmission effect of the vehicle's electrical modules without requiring any PC software or oscilloscope. It requires minimal operator expertise, is easy to operate, has a simple and compact structure, is small in size and light in weight, and is convenient to transport and carry. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1This is a schematic diagram of the circuit structure of a test device for detecting the performance of a vehicle's CAN serial port and LIN serial port, according to Embodiment 1 of the present invention.

[0029] Figure 2 This is an enlarged schematic diagram of the main control circuit of the test device for detecting the performance of the CAN serial port and LIN serial port of a vehicle, according to Embodiment 1 of the present invention.

[0030] Figure 3 This is an enlarged schematic diagram of the detection signal input circuit of the test device for detecting the performance of the CAN serial port and LIN serial port of a vehicle, according to Embodiment 1 of the present invention.

[0031] Figure 4 This is an enlarged schematic diagram of the CAN signal recognition circuit of the test device for detecting the performance of the CAN serial port and LIN serial port of a vehicle, according to Embodiment 1 of the present invention.

[0032] Figure 5 This is an enlarged schematic diagram of the LIN signal recognition circuit of the test device for detecting the performance of a vehicle's CAN serial port and LIN serial port, according to Embodiment 1 of the present invention.

[0033] Figure 6 This is an enlarged schematic diagram of the display circuit of the test device for detecting the performance of the CAN serial port and LIN serial port of a vehicle, according to Embodiment 1 of the present invention.

[0034] Figure 7 This is an enlarged schematic diagram of the power supply circuit of the test device for detecting the performance of the CAN serial port and LIN serial port of a vehicle, according to Embodiment 1 of the present invention.

[0035] Figure 8 This is an enlarged schematic diagram of the indicator light circuit of the test device used to detect the performance of the CAN serial port and LIN serial port of a vehicle, according to Embodiment 1 of the present invention. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the accompanying drawings.

[0037] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive element, but such modifications are protected by patent law as long as they fall within the scope of the claims of the present invention.

[0038] like Figures 1-8As shown, this invention provides a testing device for detecting the performance of vehicle CAN and LIN serial ports. The overall design is as follows: A simple tester housing is manufactured using a common mold. The housing is approximately 100mm × 70mm × 20mm in size, making it small, lightweight, portable, and space-saving. A PCB substrate is fixedly mounted in the upper part of the housing cavity, and a battery compartment is provided in the lower part of the housing cavity. A rechargeable battery or a dry cell battery can be installed inside the battery compartment to provide power for the testing device for detecting the performance of vehicle CAN and LIN serial ports.

[0039] The specific technical solution of Embodiment 1 is as follows:

[0040] The main control circuit, detection signal input circuit, CAN signal recognition circuit, LIN signal recognition circuit, display circuit and power supply circuit are integrated on the PCB substrate; the detection signal input circuit, CAN signal recognition circuit, LIN signal recognition circuit, display circuit and power supply circuit are all connected to the main control circuit.

[0041] The present invention provides a testing device for detecting the performance of a vehicle's CAN and LIN serial ports. The device has two operating modes: a CAN signal detection mode and a LIN signal detection mode. The main control circuit drives the CAN signal recognition circuit or the LIN signal recognition circuit to perform calculations based on the signals collected by the detection signal input circuit, and outputs the CAN signal recognition data information or the LIN signal recognition data information through the display circuit. The power supply circuit provides power to all components.

[0042] The main control circuit, based on the level signal acquired by the detection signal input circuit, drives the CAN signal recognition circuit or LIN signal recognition circuit to identify the presence or absence of data communication input and the polarity of the input signal. It then processes the signal and converts it into digital information, including the baud rate, and outputs the CAN signal recognition data or LIN signal recognition data through the display circuit. The CAN signal recognition data includes at least CAN high level, CAN low level, and the CAN bus baud rate; the LIN signal recognition data includes at least the LIN bus baud rate.

[0043] A power button switch is installed in the power supply circuit, which can be used to control the working state of the power supply circuit; the power button switch can also be used to switch between CAN signal detection mode and LIN signal detection mode.

[0044] The core structure of the main control circuit is the main control chip U3, which uses an industrial-grade general-purpose 32-bit microcontroller.

[0045] In Example 1, the main control chip U3 uses an APM32F072 microcontroller; the APM32F072 microcontroller is a microcontroller based on... High-quality domestically produced 32-bit general-purpose microcontrollers (MCUs) with M0+ / M3 / M4 cores feature low power consumption, high performance, high integration, and fast migration. With superior system performance, rich co-processing functions, and a flexible user experience, they help users shorten product design time, reduce development costs, and optimize product performance. They are widely used in industrial control, medical equipment, automotive electronics, smart homes, and other fields. In this example, a 48-pin APM32F072 C8T6 or APM32F072 CBT6 microcontroller in an LQFP48 package can be used.

[0046] Furthermore, the core structure of the detection signal input circuit consists of two relays, the first relay K1 and the second relay K2, along with the eighth diode D8, the ninth diode D9, the fifth field-effect transistor Q5, and the sixth field-effect transistor Q6. The second relay K2 allows switching between CAN signal detection mode and LIN signal detection mode. The first relay K1 allows switching between CAN high-level mode and CAN low-level mode within the CAN signal detection mode.

[0047] The operating mode of the first relay K1 can be controlled by the fifth field-effect transistor Q5 and the eighth diode D8; the operating mode of the second relay K2 can be controlled by the sixth field-effect transistor Q6 and the ninth diode D9.

[0048] The CANHL and CAN-LIN ports of the detection signal input circuit are connected to pin 21 (PB10 / I2C2_SCL) and pin 22 (PB11 / I2C2_SDA) of the main control chip U3.

[0049] This invention relates to a testing device for detecting the performance of a vehicle's CAN and LIN serial ports. All circuit structures are integrated onto a single PCB substrate, which is mounted via a housing. A power button switch is located on the side of the housing, an LCD screen is located at the top of the front of the housing, and two probe holes are located in the center of the front of the housing. The two probe holes correspond to the P+ and P- ports, respectively. Universal multimeter leads can be connected through the probe holes to detect the data information of the vehicle's CAN / LIN serial ports.

[0050] The device can be turned on by briefly pressing the power button. After turning on, briefly pressing the power button again will enter the initial working mode, which is the CAN signal detection mode. In this mode, the first relay K1 will continuously and regularly engage and disengage. Pressing the power button again will switch to the LIN signal detection mode. In other words, a short press of the power button can switch between the LIN signal detection mode and the CAN signal detection mode. Pressing and holding the power button will turn off the device.

[0051] Both the first relay K1 and the second relay K2 are HFD4 / 5-S1 eight-pin surface-mount through-hole ultra-thin miniature signal relays. In CAN signal detection mode, if the P+ port input is CANH (i.e., CAN high-level signal) and the P- port input is CANL (i.e., CAN low-level signal), the main control chip U3 controls the first relay K1 to be energized and turned on through the fifth field-effect transistor Q5 and the eighth diode D8, and it will no longer operate, operating normally in CAN high-level mode. Conversely, if the P+ port input is CANL and the P- port input is CANH, the main control chip U3 controls K1 to be de-energized and not turned on through the fifth field-effect transistor Q5 and the eighth diode D8, thus reversing the polarity. This ensures that the CAN high-level signal acquired by the P+ port or the P- port is sent to the CANH port of the CAN signal recognition circuit, and the CAN low-level signal acquired by the P- port or the P+ port is sent to the CANL port of the CAN signal recognition circuit, i.e., CAN low-level mode.

[0052] Furthermore, the core structure of the CAN signal identification circuit is a SIT1040 high-speed CAN bus transceiver chip U2. The transmitter data input terminal TXD of the CAN bus transceiver chip U2 is connected to the PB9 control port of the main control chip U3, and the receiver data output terminal RXD is connected to the PB8 control port of the main control chip U3. The low-potential CAN voltage input / output terminal CANL of the CAN bus transceiver chip U2 is connected to the NC1 port of the second relay K2 of the detection signal input circuit, and the high-potential CAN voltage input / output terminal CANH is connected to the NC2 port of the second relay K2 of the detection signal input circuit.

[0053] Furthermore, a protection circuit is provided between the CAN voltage input / output terminal CANL and the high-potential CAN voltage input / output terminal CANH of the CAN bus transceiver chip U2. The protection circuit is connected to the PA1 control port and PB0 control port of the main control chip U3.

[0054] The CAN signal recognition circuit identifies whether there is data communication input at the P- and P+ ports, the polarity of the input signal, and processes it into digital information including CAN high level, CAN low level, and CAN bus baud rate.

[0055] Furthermore, the core structure of the LIN signal recognition circuit is a LIN transceiver U6, which uses a SIT1021TLIN transceiver. The LIN bus input / output port of the LIN transceiver U6 is connected to the NO2 port of the second relay K2. The RXD receiver data output (open-drain) port of the LIN transceiver U6 is connected to the PA10 control port of the main control chip U3, the TXD transmitter data input port is connected to the PA9 control port of the main control chip U3, and the SLP_N enable input port is connected to the PA15 control port of the main control chip U3.

[0056] The LIN signal recognition circuit can also identify whether there is data communication input on the P- and P+ ports, the polarity of the input signal, and perform calculations to convert it into digital information, including the LIN bus baud rate.

[0057] The LIN bus input / output ports of the LIN transceiver U6 are also connected to the PB13 control port and PB1 control port of the main control chip U3 through a voltage detection circuit.

[0058] When the device is powered on and enters the CAN signal detection mode, the main control chip U3 drives the first relay K1 to continuously engage and disengage in a cyclical manner. When the main control chip U3 detects a 500kbps signal input at the same frequency, it displays BAUD:500kbps.

[0059] The main control chip U3 determines the polarity of the P+ and P- ports based on whether the first relay K1 is engaged. The CAN bus transceiver chip U2 receives the information about whether the first relay K1 is engaged and first displays the polarity. After receiving the differential signals from the low-potential CAN voltage input / output terminal CANL and the high-potential CAN voltage input / output terminal CANH, the CAN bus transceiver chip U2 uses a protection circuit to suppress surge pulse signals and filters them through filter L1. The main control chip U3 then drives the CAN bus transceiver chip U2 to process the level signals into digital information and displays the data information of the CAN serial port on the LCD screen through the display circuit.

[0060] The LIN signal recognition circuit identifies whether there is LIN data communication input on the P- and P+ ports, the polarity of the input signal, and performs calculations to convert it into digital information, including the LIN bus baud rate.

[0061] In LIN signal detection mode, the P+ port always displays the LIN signal, and the P- port always displays the GND ground signal. In LIN signal detection mode, if there is a LIN signal input at the P+ port, the second relay K2 will activate and the LIN transceiver U6 will receive a signal input. The main control chip U3 will drive the LIN transceiver U6 to perform calculations and processing to obtain digital information, including the LIN bus baud rate, and then display the data information of the LIN serial port on the LCD screen through the display circuit.

[0062] Conversely, if there is a LIN signal input to P-, the second relay K2 will not operate, the LIN transceiver U6 will not have a signal input, and the LCD screen will not display the data information of the LIN serial port of the communication line.

[0063] Furthermore, the display circuit is connected to the PB15, PB14, PB12, PA5, and PA6 control ports of the main control chip U3.

[0064] Finally, the core structure of the power supply circuit consists of a three-terminal positive voltage regulator U1, a linear regulator U5, and a boost inverter U7. The SW port of the power supply circuit is connected to the PA7 control port of the main control chip U3, the POW_EN port is connected to the PA4 control port of the main control chip U3, the BATT_ADC port is connected to the PA0 control port of the main control chip U3, and the LIN_POWER_DISEN port is connected to the PC13 control port of the main control chip U3.

[0065] U1 uses the 78LXX series three-terminal positive power supply voltage regulator. The 78LXX series three-terminal positive power supply voltage regulator is a monolithic and bipolar linear integrated circuit. The 78LXX series has a series of nationally standardized voltage outputs and is suitable for applications requiring a 100mA power supply. The 78LXX series mainly uses TO-92 or SOT89 packages.

[0066] The linear regulator U5 uses the ME6209A33M3G linear regulator (LDO).

[0067] The U7 boost inverter uses the MT3608 single-output boost converter, specifically the MT3608 high-efficiency 1.2MHz 2A boost inverter. The MT3608 is a constant-frequency, 6-pin SOT 23 current-mode step converter designed for small, low-power applications. The MT3608 has a switching frequency of 12MHz, allowing the use of miniature, low-cost capacitors. The height of the S and inductor does not exceed 2mm. The MT3608 features automatic switching to pulse frequency modulation mode under light loads. The MT3608 includes undervoltage lockout, current limiting, and thermal overload protection to prevent damage.

[0068] The boost inverter U7 can provide VCC-12V voltage, the three-terminal positive voltage regulator U1 can provide VCC-5V voltage, and the linear regulator U5 can provide VCC-3V3 voltage.

[0069] This invention provides a testing device for detecting the performance of a vehicle's CAN serial port and LIN serial port, and also includes a clock wake-up circuit, an encryption circuit, an indicator light circuit, and a programming port circuit.

[0070] The clock wake-up circuit is connected to the PF0-OSC_IN control port, PF1-OSC_OUT control port, and NRST control port of the main control chip U3 through the OSC_IN port, OSC_OUT port, and NRST port.

[0071] The core structure of the encryption circuit is an encryption chip U8, which uses the SMEC98SP encryption chip. The SMEC98SP employs an enhanced 8051 smart card core, allowing users to download key functions and algorithm code from the MCU program to the SMEC98SP for execution. Users write the program code in standard C language using the KEIL C compiler, compile it, and download it to the encryption chip. During actual operation, the results from the encryption chip are obtained via I2C communication and used as input data for the MCU program. Therefore, the SMEC98SP becomes an integral part of the product, and since some key functions or algorithms run internally within the SMEC98SP, it cannot be cracked by pirates, fundamentally eliminating the possibility of program tampering.

[0072] The two ports of the encryption chip U8, SMEC_SCL and SMEC_SDA, are connected to the PB7 / USART1_RX / I2C1_SDA and PB6 / USART1_TX / I2C1_SCL control ports of the main control chip U3.

[0073] The SWDIO and SWCLK ports of the programming port circuit are connected to the PA13 / SWDIO control port and PA14 / AWCLK control port of the main control chip U3.

[0074] The LEDR and LEDB ports of the indicator light circuit are connected to the PB4 / TMR3 CH1 and PB5 / TMR3 CH2 control ports of the main control chip U3.

[0075] This invention relates to a testing device for detecting the performance of a vehicle's CAN and LIN serial ports. The device includes a main control circuit, a detection signal input circuit, a CAN signal recognition circuit, a LIN signal recognition circuit, a display circuit, and a power supply circuit. It features both CAN and LIN signal detection modes. The main control circuit drives the CAN or LIN signal recognition circuit to perform calculations based on signals acquired by the detection signal input circuit, and outputs CAN or LIN signal recognition data information through the display circuit. The power supply circuit provides electrical energy. This device can directly detect the data communication transmission effect of the vehicle's electrical modules without requiring any PC software or oscilloscope. It requires minimal operator expertise, is easy to operate, has a simple and compact structure, is small in size and light in weight, and is convenient to transport and carry.

[0076] D8, D9: B5819W Schottky diodes.

[0077] Q5, Q6: 2N7002 field-effect transistors.

[0078] This invention relates to a testing device for detecting the performance of a vehicle's CAN serial port and LIN serial port. The actual functions of the product during operation are as follows:

[0079] The WOYO CAN LIN Tester is a digital tester specifically designed for automotive electronics. It can be used online or offline to test the communication status of CAN and LIN lines, checking for normal operation and data transmission. The tester automatically identifies CAN-High and CAN-Low, and automatically detects the baud rate (CAN: 100-125-150-200-250-300-400-500-666-800-1000kbps) (LIN: 2400-4800-9600-14400-19200bps). Input Voltage: 9Volt.

[0080] 1. Automatically identifies CAN-HIGH and CAN-LOW;

[0081] 2. Automatically identifies baud rate;

[0082] 3. Automatically detect whether there is data communication on the serial port.

[0083] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. The present invention is not limited to the above optional embodiments. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention, regardless of any changes in its shape or structure, should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A testing device for detecting the performance of a vehicle's CAN serial port and LIN serial port, characterized in that: It includes a main control circuit, a detection signal input circuit, a CAN signal recognition circuit, a LIN signal recognition circuit, a display circuit, and a power supply circuit; the detection signal input circuit, the CAN signal recognition circuit, the LIN signal recognition circuit, the display circuit, and the power supply circuit are all connected to the main control circuit; The testing device for detecting the performance of the vehicle's CAN serial port and LIN serial port has a CAN signal detection working mode and a LIN signal detection working mode. The main control circuit is used to drive the CAN signal recognition circuit or the LIN signal recognition circuit to perform calculations based on the signals collected by the detection signal input circuit, and outputs CAN signal recognition data information or LIN signal recognition data information through the display circuit; the CAN signal recognition data information includes at least CAN high level, CAN low level and CAN bus baud rate; the LIN signal recognition data information includes at least LIN bus baud rate. The power supply circuit is used to provide electrical energy; The main control circuit includes a main control chip U3, which is an industrial-grade general-purpose 32-bit microcontroller. The detection signal input circuit includes a first relay K1 and a second relay K2; The first relay K1 is used to switch to CAN high-level mode or CAN low-level mode when the CAN signal detection working mode is activated. The second relay K2 is used to switch between CAN signal detection mode and LIN signal detection mode; The CAN signal identification circuit includes a CAN bus transceiver chip U2. The transmitter data input terminal TXD of the CAN bus transceiver chip U2 is connected to the PB9 control port of the main control chip U3, and the receiver data output terminal RXD is connected to the PB8 control port of the main control chip U3. The low-potential CAN voltage input / output terminal CANL of the CAN bus transceiver chip U2 is connected to the NC1 port of the second relay K2 in the detection signal input circuit, and the high-potential CAN voltage input / output terminal CANH is connected to the NC2 port of the second relay K2 in the detection signal input circuit. The power supply circuit includes a three-terminal positive voltage regulator U1, a linear regulator U5, and a boost inverter U7. The boost inverter U7 is used to provide VCC-12V voltage, the three-terminal positive voltage regulator U1 is used to provide VCC-5V voltage, and the linear regulator U5 is used to provide VCC-3V3 voltage.

2. The testing device for detecting the performance of a vehicle's CAN serial port and LIN serial port according to claim 1, characterized in that: The power circuit is equipped with a power button switch, which is also used to switch between CAN signal detection mode and LIN signal detection mode.

3. The testing device for detecting the performance of a vehicle's CAN serial port and LIN serial port according to claim 1, characterized in that: The detection signal input circuit also includes an eighth diode D8, a ninth diode D9, a fifth field-effect transistor Q5, and a sixth field-effect transistor Q6; The fifth field-effect transistor Q5 and the eighth diode D8 are used to control the operating mode of the first relay K1; The sixth field-effect transistor Q6 and the ninth diode D9 are used to control the operating mode of the second relay K2; The LIN signal identification circuit includes a LIN transceiver U6, whose LIN bus input / output port is connected to the NO2 port of the second relay K2; The RXD receiver data output port of the LIN transceiver U6 is connected to the PA10 control port of the main control chip U3, the TXD transmitter data input port is connected to the PA9 control port of the main control chip U3, and the SLP_N enable input port is connected to the PA15 control port of the main control chip U3. The LIN bus input / output ports of the LIN transceiver U6 are also connected to the PB13 control port and PB1 control port of the main control chip U3 through a voltage detection circuit; The display circuit is connected to the PB15 control port, PB14 control port, PB12 control port, PA5 control port and PA6 control port of the main control chip U3.

4. The testing device for detecting the performance of a vehicle's CAN serial port and LIN serial port according to claim 1, characterized in that: A protection circuit is also provided between the CAN voltage input / output terminal CANL and the high-potential CAN voltage input / output terminal CANH of the CAN bus transceiver chip U2. The protection circuit is connected to the PA1 control port and PB0 control port of the main control chip U3.

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