Communication takeover circuit, method, controller, system and electric vehicle for controller

Abstract

The present invention provides a controller communication takeover circuit, method, controller, system, and electric vehicle, belonging to the field of communication control technology for electric vehicle controllers. The circuit includes a first microcontroller unit, a second microcontroller unit, a control circuit, and a communication transceiver; the control circuit includes at least a first signal converter, a second signal converter, a third signal converter, and a fourth signal converter; the GPIO control pin of the second microcontroller unit is connected to the TX port of the first microcontroller unit via a level control circuit. The present invention solves the problem of bus communication failure if the main MCU fails, meeting the safety requirements of electric vehicles while eliminating the need for additional communication transceiver chips and associated circuits, thus saving costs.

Description

Technical Field

[0001] The present invention relates to the technical field of communication control for electric vehicle controllers, and in particular to a communication takeover circuit, method, controller, system and electric vehicle for the controller. Background Art

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

[0003] With the development requirements of electric vehicle safety, intelligent driving, smart cockpit, energy conservation and environmental protection, many new automotive electronic control systems have emerged. Large amounts of data need to be communicated between these controllers. The main communication methods include LIN, CAN, CANFD, FlexRay, etc.

[0004] The inventors discovered that the above-mentioned communication methods are basically composed of an MCU (Microcontroller Unit) and a corresponding communication transceiver chip. Once the MCU fails, such as running away or having its own hardware failure, the message information sent by the controller to the communication bus will be in an uncontrollable state, affecting the signal processing logic of the other controllers on the bus for the faulty controller. In severe cases, it will affect the driving safety of the electric vehicle. Summary of the Invention

[0005] In order to address the deficiencies of the prior art, the present invention provides a communication takeover circuit, method, controller, system and electric vehicle for a controller, which solves the problem of bus communication failure when the main MCU fails, meets the safety requirements of electric vehicles, and does not require the addition of additional communication transceiver chips and auxiliary circuits, thereby saving costs.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A first aspect of the present invention provides a communication takeover circuit for a controller.

[0008] A communication takeover circuit for a controller, comprising:

[0009] a first micro control unit, a second micro control unit, a control circuit, and a communication transceiver;

[0010] The control circuit includes at least: a first signal converter, a second signal converter, a third signal converter and a fourth signal converter;

[0011] The transmitting port of the first microcontroller unit is connected to the receiving port of the communication transceiver via a first signal converter, the transmitting port of the second microcontroller unit is connected to the receiving port of the communication transceiver via a second signal converter, and the output end of the first signal converter and the output end of the second signal converter are connected to a power supply via a first resistor.

[0012] The transmitting port of the communication transceiver is connected to the input end of the third signal converter and the input end of the fourth signal converter respectively, the output end of the third signal converter is connected to the receiving port of the first micro control unit, and the output end of the fourth signal converter is connected to the receiving port of the second micro control unit;

[0013] The control pin of the second micro control unit is connected to the sending port of the first micro control unit through a level control circuit.

[0014] As an optional implementation, the level control circuit includes: a PMOS transistor, an NMOS transistor, a second resistor, and a third resistor;

[0015] The gate of the PMOS tube is connected to the drain of the NMOS tube, the source of the PMOS tube is connected to the power supply, and the source of the PMOS tube is connected to the drain of the NMOS tube through a second resistor;

[0016] The source of the NMOS tube is grounded, and the gate of the NMOS tube is connected to the control pin of the first micro control unit through a third resistor.

[0017] As an optional implementation, the output end of the fourth signal converter is connected to the power supply through a fourth resistor, and the output end of the third signal converter is connected to the power supply through a fifth resistor.

[0018] As an optional implementation, the power supply is +5V.

[0019] As an optional implementation, the value range of the first resistor is: greater than or equal to 0.5 KΩ and less than or equal to 10 KΩ.

[0020] As an optional implementation, the first signal converter, the second signal converter, the third signal converter and the fourth signal converter have the same structure, and all include a NOT gate and an NMOS tube. The input end of the NOT gate serves as the input end of the signal converter, the output end of the NOT gate is connected to the gate of the NMOS tube, the source of the NMOS tube is grounded, and the drain of the NMOS tube serves as the output end of the signal converter.

[0021] A second aspect of the present invention provides a communication takeover method for a controller.

[0022] A controller communication takeover method, utilizing the controller communication takeover circuit described in the first aspect of the present invention, includes the following steps:

[0023] When the second microcontroller detects that the first microcontroller is operating abnormally, it outputs a high-level signal through the control pin of the second microcontroller, thereby causing the level control circuit to output a high-level signal to the transmitting port of the first microcontroller, and the output of the first signal converter is in a high-impedance state;

[0024] The output serial port signal of the second micro control unit changes from a continuous high level state to a low level state, and communicates normally with the communication transceiver through the second signal converter.

[0025] As an optional implementation, the second microcontroller unit monitors the operation of the first microcontroller unit in real time. When it is detected that the first microcontroller unit is operating normally, the output serial port pin of the second microcontroller unit continuously outputs a high level.

[0026] The output of the second signal converter is in a high-impedance state. This state does not affect the output signal waveform of the first signal converter. The sending port of the first micro control unit sends signals normally. When the sending port of the first micro control unit is at a low level, the first signal converter outputs a low-level signal.

[0027] When the transmitting port of the first micro control unit is at a high level, since the output terminals of the first signal converter and the second signal converter are pulled up to the corresponding voltage of the power supply through the first resistor, the output of the first signal converter is at a high level.

[0028] As an optional implementation, when the first micro control unit communicates normally with the communication transceiver, the communication transceiver first sends the communication signal to the third signal converter and the fourth signal converter through the sending port;

[0029] The signal sent from the transmitting port of the communication transceiver passes through the third signal converter to the receiving port of the first micro control unit, and then passes through the fourth signal converter to the receiving port of the second micro control unit. At this time, both the first micro control unit and the second micro control unit normally receive the transmitting port signal of the communication transceiver.

[0030] As an optional implementation, when the level control circuit includes a PMOS transistor, an NMOS transistor, a second resistor and a third resistor;

[0031] When the second microcontroller unit detects that the first microcontroller unit is working abnormally, it outputs a high-level signal through the control pin of the second microcontroller unit, and makes the gate of the NMOS tube high-level through the third resistor. When the gate of the NMOS tube is high-level, the source of the NMOS tube is grounded, the gate voltage of the NMOS tube is higher than the source voltage, the drain of the NMOS tube is connected to the ground, and the drain voltage of the NMOS tube is low-level;

[0032] Since the drain of the NMOS tube is connected to the gate of the PMOS tube, the gate voltage of the PMOS tube is also low, and the source of the PMOS tube is connected to the high-level power supply, the gate voltage of the PMOS is lower than the source voltage, the source and drain of the PMOS tube are connected, and the transmitting port of the first micro control unit is connected to the power supply, and the transmitting port of the first micro control unit is high;

[0033] When the first microcontroller unit communicates normally, the control pin of the second microcontroller unit continuously outputs a low level, the gate voltage and the source voltage of the NMOS tube are the same, the NMOS tube is in a closed state, the second resistor makes the gate voltage and the source voltage of the PMOS tube the same, the PMOS tube is continuously in a disconnected state, the PMOS tube does not affect the sending port signal of the first microcontroller unit, and when the NMOS is turned off, the second resistor keeps the gate voltage and the source voltage of the PMOS tube the same, thereby turning off the PMOS tube.

[0034] A third aspect of the present invention provides a controller, comprising the communication takeover circuit for the controller described in the first aspect of the present invention.

[0035] A fourth aspect of the present invention provides a control system, comprising the controller described in the third aspect of the present invention and at least one external controller communicatively connected to the controller.

[0036] The fifth aspect of the present invention provides a vehicle, comprising the communication takeover circuit for the controller described in the first aspect of the present invention; or, comprising the controller described in the third aspect of the present invention; or, comprising the control system described in the fourth aspect of the present invention.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The controller communication takeover circuit, method, controller, system and electric vehicle described in the present invention solve the problem of bus communication failure when the main MCU fails, meet the safety requirements of electric vehicles, and do not require additional communication transceiver chips and auxiliary circuits, thus saving costs.

[0039] 2. In the controller communication takeover circuit, method, controller, system, and electric vehicle described in the present invention, the TX pin of the backup MCU (i.e., the second microcontroller) continuously outputs a high level, which will not affect the TX signal communication between the main MCU (i.e., the first microcontroller) and the communication transceiver. The TX signal level and logic remain unchanged, and the main MCU (i.e., the first microcontroller) can normally send the TX signal to the TX pin of the communication transceiver, thereby avoiding mutual influence between the main and backup MCUs.

[0040] 3. The controller communication takeover circuit, method, controller, system, and electric vehicle of the present invention provide a third signal converter and utilize the unidirectionality of the signal converter to isolate the RX pins of the main MCU (i.e., the first microcontroller unit) and the backup MCU (i.e., the second microcontroller unit) from each other, thereby preventing them from interfering with each other. A time delay Tdelay is generated to synchronize the time delays of RX and TX.

[0041] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0043] Figure 1 This is a connection diagram of the communication takeover circuit provided in Example 1 of the present invention.

[0044] Figure 2 This is a circuit connection diagram of the signal converter provided in Example 1 of the present invention.

[0045] Figure 3 This is a circuit connection diagram of the control system provided in Example 4 of the present invention. DETAILED DESCRIPTION

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0047] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0048] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0049] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0050] Example 1:

[0051] like Figure 1As shown, embodiment 1 of the present invention provides a communication takeover circuit for a controller, including: a main MCU, a backup MCU, a communication transceiver, a control circuit and a power supply.

[0052] When the controller is operating normally, the main MCU is responsible for the controller's signal acquisition, logic control, and communication functions; the backup MCU is also responsible for the controller's signal acquisition function, while monitoring the operation of the main MCU. In the event of an abnormality in the main MCU, it is responsible for taking over the main MCU's communication functions.

[0053] The communication transceiver is responsible for transmitting the serial port signal (i.e. Figure 1 TX) into the communication signal required by the bus, such as LIN or CAN signal; at the same time, the communication transceiver converts the communication signal sent by controller 1, controller 2...controller n on the bus into a serial port signal (i.e. Figure 2 RX) is sent to the main MCU and backup MCU;

[0054] The power module is responsible for providing the +5V power required for the normal operation of all modules of the controller. Figure 1 +5V in;

[0055] The main functions of the control circuit are as follows: (1) When the main MCU is operating normally, the TX and RX signals between the main MCU and the communication transceiver are transmitted normally, and the signal levels and logic are kept consistent; (2) When the main MCU is abnormal, the TX signal of the main MCU is prohibited from being sent, and the TX signal of the backup MCU is transmitted to the communication transceiver, and the RX signal of the communication transceiver is transmitted to the backup MCU.

[0056] like Figure 1 As shown in the figure, the circuit components of the controller and the present invention are as follows. Figure 1 The control circuit has been refined.

[0057] The control circuit specifically includes: signal conversion 1 (i.e., the first signal converter), signal conversion 2 (i.e., the first signal converter), signal conversion 3 (i.e., the first signal converter), signal conversion 4 (i.e., the first signal converter), resistor R1 (i.e., the first resistor), resistor R2 (i.e., the second resistor), resistor R3 (i.e., the third resistor), resistor R4 (i.e., the fourth resistor), resistor R5 (i.e., the fifth resistor), PMOS transistor Q1 and NMOS transistor Q2.

[0058] The TX output of the main MCU is connected to the input IN of signal converter 1 and the drain (D) of the PMOS. The output OUT of signal converter 1 is connected to the TX of the communication transceiver and the first end of resistor R1. The second end of resistor R1 is connected to the power supply +5V.

[0059] The TX output of the backup MCU is connected to the input IN of the signal converter 2 , and the output OUT of the signal converter 2 is connected to the TX of the communication transceiver and the first end of the resistor R1 .

[0060] The RX output of the communication transceiver is connected to the input IN of signal conversion 3 and the input IN of signal conversion 4, the output OUT of signal conversion 3 is connected to the RX of the backup MCU and the first end of resistor R5, and the output OUT of signal conversion 4 is connected to the RX of the main MCU and the first end of resistor R4.

[0061] A second end of the resistor R4 is connected to the power supply +5V, and a second end of the resistor R5 is connected to the power supply +5V.

[0062] The gate (G) of the PMOS transistor Q1 is connected to the drain (D) of the NMOS transistor Q2 and the first end of the resistor R2. The source (S) of the PMOS transistor Q1 and the second end of the resistor R2 are both connected to the power supply +5V. The source (S) of the NMOS transistor Q2 is connected to the controller ground GND, and the gate (G) of Q2 is connected to the GPIO control pin of the backup MCU.

[0063] like Figure 2 As shown in the figure, the internal circuits of signal conversion 1, signal conversion 2, signal conversion 3, and signal conversion 4 are exactly the same. They are mainly composed of a logic NOT gate and an NMOS. The input IN of the signal converter is connected to the input of the logic NOT gate, and the output of the logic NOT gate is connected to the gate (G) of the NMOS tube Q. The source (S) of the NMOS tube Q is connected to the ground GND of the controller, and the drain (D) of the NMOS tube Q is connected to the output OUT of the signal converter. Since the NMOS tube is an open-drain output, the logical relationship between the input IN and output OUT of the signal converter is as follows:

[0064]

[0065] Since the signal converter has a Z (high-impedance) output state, this feature can be used to connect the TX outputs of the main MCU and the backup MCU in parallel to communicate with the communication transceiver, so that only one TX signal is transmitted at a time and the other TX signal is disabled, without causing mutual interference between the two TX signals.

[0066] Example 2:

[0067] Embodiment 2 of the present invention provides a controller communication takeover method, using the controller communication takeover circuit described in embodiment 1, including the following steps:

[0068] The backup MCU monitors the operation of the main MCU in real time through SPI communication. When it detects that the main MCU is operating normally, the TX pin of the backup MCU continuously outputs a high level, and the OUT of signal conversion 2 is in a high-impedance state. This state does not affect the OUT output signal waveform of signal conversion 1. That is, by pulling up the TX pin of the backup MCU, combined with signal conversion 2, the TX signal of the backup MCU is shielded;

[0069] The main MCU sends the TX signal normally. When the main MCU sends a TX low-level signal, signal conversion 1 outputs a low-level signal. When the main MCU sends a TX high-level signal, since the OUT outputs of signal conversion 1 and 2 are pulled up to +5V through resistor R1, the OUT output of signal conversion 1 is a +5V high-level signal.

[0070] The function of the pull-up resistor R1 is to pull up the +5V level of the resistor R1 to output a certain high-level signal to the OUT of signal conversion 1 or 2 when the OUT output of signal conversion 1 or 2 is in a high-impedance state;

[0071] When the output OUT of signal conversion 1 or 2 is a low-level signal, resistor R1 will not affect the low-level signal and the rising and falling edges of the signal. At the same time, resistor R1 should also play a current limiting role to prevent +5V from directly passing through the output MOS of signal conversion 1 or 2. Therefore, the resistance selection range of R1 is 0.5KΩ≤R1≤10KΩ.

[0072] Therefore, the signal relationship between the input and output of signal conversion 1 is as follows:

[0073]

[0074] In summary, the backup MCU's TX pin continuously outputs a high level, which does not affect the TX signal communication between the main MCU and the communication transceiver. The TX signal level and logic remain unchanged, and the main MCU can send TX signals to the communication transceiver's TX pin normally. Because the TX signal undergoes signal conversion 1, there is a time delay Tdelay between the input IN and the output OUT. Since the signal converter itself is a pure hardware signal conversion, this time delay Tdelay is very small, generally Tdelay ≤ 10ns, and has no impact on signal transmission.

[0075] In summary, signal converters are unidirectional, meaning signals can only flow from input IN to output OUT. Since the TX and RX signals between the main MCU or backup MCU and the communication transceiver are also directional, signal converters are very suitable for signal transmission.

[0076] When the main MCU communicates normally with the communication transceiver, the communication transceiver will also send the communication signal to signal conversion 3 and signal conversion 4 through the RX pin. The RX signal passes through signal conversion 4 to the RX pin of the main MCU and then to the RX pin of the backup MCU through signal conversion 3. At this time, both the main MCU and the backup MCU can normally receive the RX signal of the communication transceiver without affecting each other. The functions of resistors R4 and R5 are the same as those of resistor R1. They are both pull-up resistors at the output end of the signal converter OUT.

[0077] The main functions of adding signal converter 3 are: (1) utilizing the unidirectionality of the signal converter to isolate the RX pins of the main MCU and the backup MCU so that they do not affect each other; (2) generating a time delay Tdelay to synchronize the time delay of RX and TX.

[0078] When the backup MCU detects an abnormality in the main MCU through SPI, it outputs a high-level signal through the GPIO pin of the backup MCU. This signal passes through resistor R3, making the gate (G) of the NMOS transistor Q2 high. The function of resistor R3 is current limiting and signal transmission.

[0079] When the gate (G) of the NMOS tube Q2 is at a high level, since its source (S) is grounded GND, the gate (G) voltage is higher than the source (S) voltage, so the drain (D) of the NMOS tube Q2 and the ground GND are connected, and the drain (D) voltage of Q2 is low;

[0080] Since the drain (D) of Q2 is connected to the gate (G) of the PMOS tube Q1, the gate (G) voltage of the PMOS tube Q1 is also low, and the source (S) of the PMOS tube Q1 is connected to the +5V high level, resulting in the gate (G) voltage of Q1 being lower than the source (S) voltage. The source (S) and drain (D) of the PMOS tube Q1 are turned on, connecting the TX pin of the main MCU to the +5V power supply, forcing the TX pin of the main MCU to be pulled high. Since the TX signal conversion 1 of the main MCU is connected to the input IN, the IN of the signal conversion 1 is high. Due to the characteristics of the signal conversion 1, when the input IN is high, the output is in a high impedance state.

[0081] Similar to the above-mentioned shielding of the backup MCU's TX function, when the main MCU works abnormally, the TX function of the main MCU is shielded by pulling the input IN of the signal conversion 1 high.

[0082] At the same time as the TX function of the main MCU is blocked, the TX signal of the backup MCU changes from the previous continuous high-level state to the normal sending state, and communicates normally with the communication transceiver through signal conversion 2. The working principle is the same as the communication principle between the TX of the main MCU and the communication transceiver, which will not be repeated here;

[0083] The RX signal sent by the communication transceiver can be normally received by the RX pin of the backup MCU after conversion through signal conversion 3. The communication principle of the RX signal is consistent with that of the main MCU and will not be repeated here. In this way, while shielding the communication between the main MCU and the communication transceiver, normal communication between the backup MCU and the communication transceiver can be achieved, achieving the purpose of the backup MCU taking over the communication of the main MCU in an emergency.

[0084] When the main MCU is communicating normally, the GPIO pin of the backup MCU connected to resistor R3 continuously outputs a low level, the gate (G) voltage and source (S) voltage of the NMOS tube Q2 are the same, and Q2 is in the off state. At this time, due to the presence of pull-up resistor R2, the gate (G) voltage and source (S) voltage of the PMOS tube are the same, and the PMOS tube Q1 is continuously in the off state. Q1 will not affect the TX signal of the main MCU. The function of pull-up resistor R2 is to keep the gate (G) voltage and source (S) voltage of Q1 the same when Q2 is turned off, thereby turning off Q1.

[0085] The communication transceiver in the above example uses two-line communication, TX and RX, but it can actually use multi-line communication.

[0086] Example 3:

[0087] Embodiment 3 of the present invention provides a controller, including the communication takeover circuit for the controller described in embodiment 1.

[0088] Example 4:

[0089] like Figure 3 As shown, embodiment 4 of the present invention provides a control system, including the controller described in embodiment 3, wherein information communication between the controller and controller 1, controller 2... and controller n is performed via a communication bus, and the number of communication buses can be single (such as LIN communication) or dual (such as CAN communication, etc.).

[0090] Example 5:

[0091] Embodiment 5 of the present invention provides a vehicle, comprising the communication takeover circuit for the controller described in Embodiment 1 of the present invention; or, comprising the controller described in Embodiment 3 of the present invention; or, comprising the control system described in Embodiment 4 of the present invention.

[0092] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A communication control method for a controller, characterized in that: including a communication control circuit for the controller, The circuit comprises: a first micro control unit, a second micro control unit, a control circuit, and a communication transceiver; The control circuit includes at least: a first signal converter, a second signal converter, a third signal converter and a fourth signal converter; The transmitting port of the first microcontroller unit is connected to the receiving port of the communication transceiver via a first signal converter, the transmitting port of the second microcontroller unit is connected to the receiving port of the communication transceiver via a second signal converter, and the output end of the first signal converter and the output end of the second signal converter are connected to a power supply via a first resistor. The transmitting port of the communication transceiver is connected to the input end of the third signal converter and the input end of the fourth signal converter respectively, the output end of the third signal converter is connected to the receiving port of the second micro control unit, and the output end of the fourth signal converter is connected to the receiving port of the first micro control unit; The control pin of the second micro control unit is connected to the sending port of the first micro control unit through a level control circuit; The method includes the following steps: When the second microcontroller detects that the first microcontroller is operating abnormally, it outputs a high-level signal through the control pin of the second microcontroller, thereby causing the level control circuit to output a high-level signal to the transmitting port of the first microcontroller, and the output of the first signal converter is in a high-impedance state; The output serial port signal of the second micro control unit changes from a continuous high level state to a low level state, and communicates normally with the communication transceiver through the second signal converter.

2. The communication control method for a controller according to claim 1, wherein: A level control circuit includes: a PMOS transistor, an NMOS transistor, a second resistor, and a third resistor; The gate of the PMOS tube is connected to the drain of the NMOS tube, the source of the PMOS tube is connected to the power supply, and the source of the PMOS tube is connected to the drain of the NMOS tube through a second resistor; The source of the NMOS tube is grounded, and the gate of the NMOS tube is connected to the control pin of the second micro control unit through a third resistor.

3. The communication control method for a controller according to any one of claims 1 to 2, characterized in that: The output end of the fourth signal converter is connected to the power supply through a fourth resistor, and the output end of the third signal converter is connected to the power supply through a fifth resistor.

4. The communication control method for a controller according to any one of claims 1 to 2, characterized in that: The power supplies are all +5V.

5. The communication control method for a controller according to claim 1, wherein: The value range of the first resistor is: greater than or equal to 0.5KΩ and less than or equal to 10KΩ.

6. The communication control method for a controller according to claim 1, wherein: The first signal converter, the second signal converter, the third signal converter and the fourth signal converter have the same structure and all include a NOT gate and an NMOS transistor. The input end of the NOT gate serves as the input end of the signal converter, the output end of the NOT gate is connected to the gate of the NMOS transistor, the source of the NMOS transistor is grounded, and the drain of the NMOS transistor serves as the output end of the signal converter.

7. The communication control method for a controller according to claim 1, wherein: The second micro control unit monitors the operation of the first micro control unit in real time. When it is detected that the first micro control unit is operating normally, the output serial port pin of the second micro control unit continuously outputs a high level. The output of the second signal converter is in a high-impedance state. This state does not affect the output signal waveform of the first signal converter. The sending port of the first micro control unit sends signals normally. When the sending port of the first micro control unit is at a low level, the first signal converter outputs a low-level signal. When the transmitting port of the first micro control unit is at a high level, since the output terminals of the first signal converter and the second signal converter are pulled up to the corresponding voltage of the power supply through the first resistor, the output of the first signal converter is at a high level.

8. The communication control method for a controller according to claim 1, wherein: When the first micro control unit communicates normally with the communication transceiver, the communication transceiver first sends the communication signal to the third signal converter and the fourth signal converter through the sending port; The signal sent from the transmitting port of the communication transceiver passes through the third signal converter to the receiving port of the second micro control unit, and then passes through the fourth signal converter to the receiving port of the first micro control unit. At this time, both the first micro control unit and the second micro control unit normally receive the transmitting port signal of the communication transceiver.

9. The communication control method for a controller according to claim 1, wherein: When the level control circuit includes a PMOS transistor, an NMOS transistor, a second resistor and a third resistor; When the second microcontroller unit detects that the first microcontroller unit is working abnormally, it outputs a high-level signal through the control pin of the second microcontroller unit, and makes the gate of the NMOS tube high-level through the third resistor. When the gate of the NMOS tube is high-level, the source of the NMOS tube is grounded, the gate voltage of the NMOS tube is higher than the source voltage, the drain of the NMOS tube is connected to the ground, and the drain voltage of the NMOS tube is low-level; Since the drain of the NMOS tube is connected to the gate of the PMOS tube, the gate voltage of the PMOS tube is also low, and the source of the PMOS tube is connected to the high-level power supply, the gate voltage of the PMOS is lower than the source voltage, the source and drain of the PMOS tube are connected, and the transmitting port of the first micro control unit is connected to the power supply, and the transmitting port of the first micro control unit is high; When the first microcontroller unit communicates normally, the control pin of the second microcontroller unit continuously outputs a low level, the gate voltage and the source voltage of the NMOS tube are the same, the NMOS tube is in a closed state, the second resistor makes the gate voltage and the source voltage of the PMOS tube the same, the PMOS tube is continuously in a disconnected state, the PMOS tube does not affect the sending port signal of the first microcontroller unit, and when the NMOS is turned off, the second resistor keeps the gate voltage and the source voltage of the PMOS tube the same, thereby turning off the PMOS tube.

10. A controller, characterized in that: The communication control method for a controller includes any one of claims 1 to 9.

11. A control system, characterized in that: The device comprises the controller according to claim 10 and at least one external controller communicatively connected to the controller.

12. A vehicle, characterized in that: It comprises a communication control circuit for executing the communication control method for a controller according to any one of claims 1 to 9; or, it comprises the controller according to claim 10; or, it comprises the control system according to claim 11.

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