MCU-based PSI5 sensor data simulation test system and method thereof

Abstract

According to the MCU-based PSI5 sensor data simulation test system and method, the circuit is simple, the cost is low, data signals of a PSI5 sensor can be rapidly simulated, and then test and development of an automobile safety air bag control system are effectively supported; the system comprises a synchronization pulse voltage reduction module which is connected with a PSI5 bus interface and is used for reducing the voltage of a PSI5 synchronization pulse output by the PSI5 bus interface; the explicit and implicit level modulation module is connected with the PSI5 bus interface and is used for realizing explicit and implicit level modulation of a PSI5 bus and transmitting a modulated level signal to the PSI5 bus interface; and the MCU processing module is connected with the synchronization pulse voltage reduction module and the explicit-implicit level modulation module, and is used for outputting a Manchester code modulation waveform to the explicit-implicit level modulation module after recognizing the PSI5 synchronization pulse subjected to voltage reduction processing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of PSI5 sensor data simulation, in particular to a PSI5 sensor data simulation test system based on MCU and a method thereof. BACKGROUND

[0002] In the development process of an automobile airbag control system, a simple and feasible method is needed to simulate the automobile collision situation to realize the rapid adjustment of the control algorithm, wherein the controller of the automobile airbag system is connected with a PSI5 sensor through a PSI5 bus to realize power supply and communication at the same time. The PSI5 bus realizes high-reliability communication in key systems such as automobile airbag and chassis control by virtue of its explicit and implicit level modulation Manchester coding and CRC check technology. However, in the development stage of the controller (ACU) of the automobile airbag system, only relying on real sensors to obtain dynamic changing acceleration physical signals will have poor real-time performance and the scene cannot be reproduced, which leads to an urgent need for a PSI5 bus simulation device, i.e. the PSI5 bus simulation device needs to be able to quickly and flexibly generate the required sensor data signals to comprehensively verify the function and reliability of the controller in the laboratory environment.

[0003] The existing PSI5 simulation technology, such as the FPGA-based scheme, mostly relies on a precise resistance array for current modulation, but this method is limited by the fixed resistance network, resulting in solidified output impedance, poor compatibility, and communication rate being restricted by the performance of the analog switch. Another V-I conversion scheme can improve flexibility, but the inherent delay of the analog circuit will cause slow current response, and the output waveform edge cannot meet the stringent timing requirements of high-speed PSI5 communication. SUMMARY

[0004] In view of the above problems, the present application provides a PSI5 sensor data simulation test system based on MCU and a method thereof, which has simple circuit and low cost, can quickly simulate the data signal of the PSI5 sensor, and effectively supports the test and development of the automobile airbag control system.

[0005] The present application adopts the following technical scheme, a PSI5 sensor data simulation test system based on MCU, comprising: A synchronous pulse step-down module connected with a PSI5 bus interface, used for step-down processing the voltage of a PSI5 synchronous pulse output by the PSI5 bus interface; An explicit and implicit level modulation module connected with the PSI5 bus interface, used for realizing the explicit and implicit level modulation of the PSI5 bus and transmitting the modulated level signal to the PSI5 bus interface; The MCU processing module is connected with the synchronous pulse voltage reduction module and the display and non-display level modulation module, and is used for outputting a Manchester code modulation waveform to the display and non-display level modulation module after identifying the PSI5 synchronous pulse subjected to voltage reduction processing.

[0006] Further, the display and non-display level modulation module comprises a voltage dividing resistor R1, a pull-down resistor R2 and a MOS tube Q1; the synchronous pulse voltage reduction module comprises a pull-down resistor R3 and a voltage stabilizing tube D1; the negative electrode of the voltage stabilizing tube D1 and one end of the voltage dividing resistor R1 are connected to the PSI5 bus interface; the positive electrode of the voltage stabilizing tube D1 is connected to the MCU processing module after being connected to one end of the pull-down resistor R3; the other end of the pull-down resistor R3 is grounded; the gate of the MOS tube Q1 is connected to the MCU processing module after being connected to one end of the pull-down resistor R2; the source of the MOS tube Q1 is connected to the other end of the pull-down resistor R2 and then grounded; and the drain of the MOS tube Q1 is connected to the other end of the voltage dividing resistor R1. Further, the breakdown voltage of the voltage stabilizing tube D1 is 9V-11V; and the voltage of the PSI5 synchronous pulse subjected to voltage reduction processing is 3V-5V. Further, the MCU processing module outputs the Manchester code modulation waveform after identifying the rising edge of the PSI5 synchronous pulse subjected to voltage reduction processing and after a delay setting time. Further, when the PSI5 bus is in an idle state, the voltage output by the PSI5 bus interface is 6-8V; and when the PSI5 bus is in a working state, the voltage output by the PSI5 bus interface is 14V. The application further provides a PSI5 sensor data simulation test method based on an MCU, comprising the following steps: S1, obtaining a PSI5 synchronous pulse signal output by a PSI5 bus interface; S2, performing voltage reduction processing on the PSI5 synchronous pulse signal, and then delivering the PSI5 synchronous pulse signal subjected to voltage reduction processing to an MCU processing module; S3, outputting a Manchester code modulation waveform to a display and non-display level modulation module by the MCU processing module after identifying the PSI5 synchronous pulse signal subjected to voltage reduction processing, performing display and non-display level modulation on the Manchester code modulation waveform by the display and non-display level modulation module, and then delivering the modulated level signal to the PSI5 bus interface, thereby completing the simulation of the data signal of the PSI5 sensor.

[0007] Further, in the step S1, the PSI5 bus is in an idle state before the PSI5 synchronous pulse signal arrives; the PSI5 bus is in a working state when the PSI5 synchronous pulse signal arrives; the PSI5 synchronous pulse signal is output through the PSI5 bus interface; and the PSI5 bus returns to the idle state after completing the signal transmission, so as to wait for the arrival of the next PSI5 synchronous pulse signal. Further, when the PSI5 bus is in an idle state, the voltage stabilizing tube D1 does not work, at this time, the IO port connected to the MCU processing module is pulled down to the ground by the pull-down resistor R3; When the PSI5 synchronization pulse signal arrives, the voltage stabilizing tube D1 works, and the step S2 is performed; Further, in the step S3, the MCU processing module outputs a Manchester code modulation waveform, when the signal in the Manchester code modulation waveform is a high level, the MOS tube Q1 is opened, and the bus voltage V1 is divided to a dominant level by the voltage dividing resistor R1; when the signal in the Manchester code modulation waveform is a low level, the MOS tube Q1 is closed, and the bus voltage V1 is not divided, that is, output to the PSI5 bus interface as a recessive level; Further, the dominant level is less than the bus voltage V1; the recessive level is the same as the bus voltage V1.

[0008] The beneficial effect of the present application is that, after the MCU processing module recognizes the PSI5 synchronization pulse signal, the Manchester code modulation waveform is sent to the dominant recessive level modulation module, thereby realizing modulation of the dominant recessive level of the PSI5 bus, and transmitting the modulated level signal to the PSI5 bus interface, so that the required PSI5 sensor data signal can be quickly and flexibly simulated, the test and development of the automobile airbag chip can be effectively supported, and the economic use value is good. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a structural block diagram of the present application; Figure 2 is a circuit principle diagram of the present application; Figure 3 is a schematic diagram of the PSI5 bus interface synchronization pulse and the Manchester code waveform in the present application. DETAILED DESCRIPTION

[0010] As shown in Figure 1 , Figure 2 , Figure 3 , a PSI5 sensor data simulation test system based on MCU of the present application comprises: A PSI5 bus interface, connected with the synchronization pulse voltage reduction module and the dominant recessive level modulation module, used for sending the PSI5 synchronization pulse and receiving the level modulated Manchester code waveform; The synchronization pulse voltage reduction module is connected with the PSI5 bus interface of the automobile electronic controller, used for reducing the voltage of the PSI5 synchronization pulse output by the PSI5 bus interface, because the maximum input level that the IO port of the MCU processing module can tolerate is 5V, so the voltage of the PSI5 synchronization pulse needs to be reduced to the voltage range that the MCU processing module can withstand; The apparent and hidden level modulation module is connected with the PSI5 bus interface and is used for receiving the Manchester code modulation waveform output by the MCU processing module, realizing the voltage division of the PSI5 bus level by controlling the on-off of the MOS tube Q1, then realizing the apparent and hidden level modulation of the PSI5 bus, and transmitting the modulated level signal to the PSI5 bus interface; The MCU processing module is connected with the synchronous pulse voltage reduction module and the apparent and hidden level modulation module, and is used for outputting the specified Manchester code modulation waveform to the apparent and hidden level modulation module after recognizing the rising edge of the voltage reduction processed PSI5 synchronous pulse and after delaying for a set time. Specifically, the MCU processing module adopts an STM32 series microcontroller which integrates a Cortex processor kernel.

[0011] The apparent and hidden level modulation module comprises a voltage division resistor R1, a pull-down resistor R2 and a MOS tube Q1; the synchronous pulse voltage reduction module comprises a pull-down resistor R3 and a voltage stabilizing tube D1; the pull-down resistor R2 can be 10000 ohms, used for providing a pull-down low level for the output port of the MCU processing module, the MOS tube Q1 is an NMOS tube; the negative electrode of the voltage stabilizing tube D1 and one end of the voltage division resistor R1 are both connected to the PSI5 bus interface, the positive electrode of the voltage stabilizing tube D1 is connected to the MCU processing module after being connected to one end of the pull-down resistor R3, the other end of the pull-down resistor R3 is grounded, the gate of the MOS tube Q1 is connected to the MCU processing module after being connected to one end of the pull-down resistor R2, the source of the MOS tube Q1 is grounded after being connected to the other end of the pull-down resistor R2, and the drain of the MOS tube Q1 is connected to the other end of the voltage division resistor R1.

[0012] The breakdown voltage of the voltage stabilizing tube D1 is 9V~11V, and the resistance value of the pull-down resistor R3 can be 10000 ohms; the voltage of the voltage reduction processed PSI5 synchronous pulse is 3V~5V; when the PSI5 bus is in an idle state, the voltage output by the PSI5 bus interface is recorded as V1, at this time, V1=6V~8V; when the PSI5 bus is in a working state, the voltage output by the PSI5 bus interface is recorded as V2, at this time, V2=14V.

[0013] The application further provides a PSI5 sensor data simulation test method based on an MCU, comprising the following steps: S1, before the arrival of a PSI5 synchronous pulse signal, the PSI5 bus is in an idle state, the voltage stabilizing tube D1 does not work, at this time, the IO port connected to the MCU processing module is pulled down to the ground by the pull-down resistor R3; When the PSI5 synchronization pulse signal arrives and the PSI5 bus is in the working state, the PSI5 synchronization pulse signal is output through the PSI5 bus interface, the voltage stabilizing tube D1 works, and the step S2 is performed, wherein, after the transmission of the PSI5 synchronization pulse signal is completed, the PSI5 bus returns to the idle state to wait for the next PSI5 synchronization pulse signal; S2, the PSI5 synchronization pulse signal output by the PSI5 bus interface is processed by voltage reduction, and then the PSI5 synchronization pulse signal processed by voltage reduction is transmitted to the MCU processing module; S3, the MCU processing module outputs the Manchester code modulation waveform to the display and non-display level modulation module for display and non-display level modulation after recognizing the rising edge of the PSI5 synchronization pulse processed by voltage reduction and after delaying for a set time, and then transmits the modulated level signal to the PSI5 bus interface, thereby completing the data signal simulation of the PSI5 sensor; Further, in the step S3, the MCU processing module outputs the Manchester code modulation waveform, when the signal in the Manchester code modulation waveform is high level, the MOS tube Q1 is opened, and the current PSI5 synchronization pulse signal voltage processed by voltage reduction is divided by the voltage dividing resistor R1 to the display level V3; when the signal in the Manchester code modulation waveform is low level, the MOS tube Q1 is closed, and the current PSI5 synchronization pulse signal voltage processed by voltage reduction is not divided (i.e. the bus voltage V1 is not divided), that is, output to the PSI5 bus interface as the non-display level; Wherein, the display level is less than the current PSI5 synchronization pulse signal voltage processed by voltage reduction; the non-display level is the same as the current PSI5 synchronization pulse signal voltage processed by voltage reduction.

[0014] The main purpose of the PSI5 synchronization pulse signal is to realize the synchronous communication and data transmission coordination between multiple nodes on the bus. Specifically, it provides a unified time reference for all sensors, actuators and other nodes connected to the PSI5 bus, ensuring that each node can orderly send and receive data within the preset time window, avoiding data transmission conflicts. Through the PSI5 synchronization pulse signal, the master node can accurately control the communication period, so that the slave node can trigger its own data sending timing based on the rising edge of the PSI5 synchronization pulse signal, thereby ensuring the accuracy, real-time and reliability of the whole bus system communication, especially suitable for distributed control systems such as automotive electronics which have high requirements for data transmission synchronization.

[0015] The working principle of the application is: The PSI5 sensor is connected to the PSI5 bus, and before the PSI5 synchronization pulse signal, the PSI5 bus is in an idle state and does not transmit data, and since the bus voltage V1 is less than the breakdown voltage of the voltage stabilizing tube D1, the voltage stabilizing tube D1 does not work, at this time, the IO port connected to the MCU processing module is pulled down to the ground by the pull-down resistor R3; After the PSI5 synchronization pulse signal, the PSI5 bus is in a working state, and the PSI5 sensor needs to send data to the PSI5 bus within a specific time window. Since the voltage V2 of the PSI5 synchronization pulse signal is greater than the breakdown voltage of the voltage stabilizing tube D1, the voltage across the voltage stabilizing tube D1 is maintained at 9V~11V, and the pulse voltage connected to the MCU processing module is at 3V~5V; thus, a voltage stabilizing tube D1 and a pull-down resistor R3 form a synchronization pulse voltage reduction module, which is simple in circuit and low in cost; Manchester coding is a kind of existing bit synchronization coding mode, each coding data group contains 2 start bits, 10 data bits and 1 parity check bit or 3 CRC check bits, in this embodiment, 2 start bits (S1, S2), 10 data bits (D0~D9) and 1 parity check bit P are contained; the specific rules are as shown in Figure 3 As shown in the figure, a level jump must occur in the middle of each data bit, and the direction of the jump determines the value of the bit, from low to high indicating "1"; from high to low indicating "0".

[0016] The MOS tube Q1 acts as a switch tube, and its gate receives the Manchester code modulation waveform output by the MCU processing module, so that the MOS tube Q1 can be opened or closed according to the high and low of the Manchester code modulation waveform level, the high level is 3.3V, and the low level is 0V; the resistance of the voltage dividing resistor R1 can be 80 ohms, and the PSI5 bus interface has an internal resistance of about 15 ohms; when the MCU processing module outputs a high level, the MOS tube Q1 is opened, the voltage dividing resistor R1 is connected to the ground, the bus voltage V1 is divided to V3, i.e. the explicit level, and the voltage V3 is less than the voltage V1; when the MCU processing module outputs a low level, the MOS tube Q1 is closed, the bus voltage is not divided, and the V1 state is maintained, i.e. the implicit level; thus, the Manchester code modulation waveform output by the MCU processing module can be used to realize the explicit and implicit level modulation on the PSI5 bus.

[0017] It will be obvious to a person skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments and can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference signs in the claims should be considered as limiting the scope of the claims to the identity of the reference signs therein.

[0018] Furthermore, it should be understood that although the description is made on the basis of the embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A PSI5 sensor data simulation and testing system based on an MCU, characterized in that: include: A synchronous pulse step-down module is connected to the PSI5 bus interface and is used to step down the voltage of the PSI5 synchronous pulse output from the PSI5 bus interface. The explicit / implicit level modulation module is connected to the PSI5 bus interface and is used to implement explicit / implicit level modulation of the PSI5 bus and transmit the modulated level signal to the PSI5 bus interface. The MCU processing module is connected to both the synchronous pulse buck module and the explicit / implicit level modulation module. After recognizing the buck-processed PSI5 synchronous pulse, it outputs a Manchester code modulated waveform to the explicit / implicit level modulation module.

2. The MCU-based PSI5 sensor data simulation and testing system according to claim 1, characterized in that: The display / concealment level modulation module includes a voltage divider resistor R1, a pull-down resistor R2, and a MOSFET Q1; the synchronous pulse buck module includes a pull-down resistor R3 and a Zener diode D1; the negative terminal of the Zener diode D1 and one end of the voltage divider resistor R1 are both connected to the PSI5 bus interface, the positive terminal of the Zener diode D1 is connected to one end of the pull-down resistor R3 and then connected to the MCU processing module, the other end of the pull-down resistor R3 is grounded, the gate of the MOSFET Q1 is connected to one end of the pull-down resistor R2 and then connected to the MCU processing module, the source of the MOSFET Q1 is connected to the other end of the pull-down resistor R2 and then grounded, and the drain of the MOSFET Q1 is connected to the other end of the voltage divider resistor R1.

3. The MCU-based PSI5 sensor data simulation and testing system according to claim 2, characterized in that: The breakdown voltage of the Zener diode D1 is 9V~11V; the voltage of the PSI5 synchronization pulse after voltage reduction is 3V~5V.

4. The MCU-based PSI5 sensor data simulation and testing system according to claim 1, characterized in that: After recognizing the rising edge of the PSI5 synchronization pulse during the buck processing, the MCU processing module outputs a Manchester code modulated waveform after a set delay.

5. The MCU-based PSI5 sensor data simulation and testing system according to claim 1, characterized in that: When the PSI5 bus is in an idle state, the voltage output by the PSI5 bus interface is 6~8V; when the PSI5 bus is in an active state, the voltage output by the PSI5 bus interface is 14V.

6. A method for simulating and testing PSI5 sensor data based on an MCU, characterized in that: Includes the following steps: S1. Obtain the PSI5 synchronization pulse signal output from the PSI5 bus interface; S2. Step down the voltage of the PSI5 synchronization pulse signal, and then send the step-down PSI5 synchronization pulse signal to the MCU processing module. After recognizing the buck-processed PSI5 synchronization pulse signal, the S3 and MCU processing modules output a Manchester code modulated waveform to the explicit / implicit level modulation module for explicit / implicit level modulation. Subsequently, the modulated level signal is transmitted to the PSI5 bus interface, thus completing the simulation of the PSI5 sensor's data signal.

7. The method for simulating and testing PSI5 sensor data based on an MCU according to claim 6, characterized in that: In step S1, the PSI5 bus is in an idle state before the PSI5 synchronization pulse signal arrives; when the PSI5 synchronization pulse signal arrives, the PSI5 bus is in a working state, and the PSI5 synchronization pulse signal is output through the PSI5 bus interface. After the signal transmission is completed, the PSI5 bus returns to an idle state to wait for the next PSI5 synchronization pulse signal to arrive.

8. The MCU-based PSI5 sensor data simulation test method according to claim 7, characterized in that: When the PSI5 bus is idle, the Zener diode D1 is not working. At this time, the IO port connected to the MCU processing module is pulled down to ground by the pull-down resistor R3. When the PSI5 synchronization pulse signal arrives, the Zener diode D1 operates and performs step S2.

9. The method for simulating and testing PSI5 sensor data based on an MCU according to claim 6, characterized in that: In step S3, the MCU processing module outputs a Manchester code modulation waveform. When the signal in the Manchester code modulation waveform is high, the MOSFET Q1 is turned on, and the bus voltage V1 is divided to the dominant level through the voltage divider resistor R1. When the signal in the Manchester code modulation waveform is low, the MOSFET Q1 is turned off, and the bus voltage V1 is not divided, that is, it is output to the PSI5 bus interface as the recessive level.

10. The MCU-based PSI5 sensor data simulation test method according to claim 9, characterized in that: The dominant voltage level is less than the bus voltage V1; the recessive voltage level is the same as the bus voltage V1.

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