Data synchronization method of safety air bag ignition system

Abstract

The invention relates to the technical field of safety air bag ignition, and discloses a data synchronization method of a safety air bag ignition system. In actual use, a preset interval for sending a synchronization pulse signal is set based on a clock of a master control MCU and a clock of an ignition control chip; then the ignition control chip controls the clock frequency of an acceleration sensor on the PSI5 bus based on a preset interval, so that the communication influence of the clock skew of the main control MCU on the whole ignition system is removed; in addition, the ignition control chip adjusts the preset interval of the synchronous pulse signals by monitoring the interval of sensor data on the PSI5 bus, so that the conditions that the interval of the sensor data on the PSI5 bus is too short and data is disordered are avoided; and finally, the main control MCU reads the data according to the interval of the heartbeat pulse signals, so that the integrity and the real-time performance of the read data can be ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of airbag ignition technology, and particularly relates to a data synchronization method of an airbag ignition system. BACKGROUND

[0002] The automobile airbag is one of the core components of the passive safety system of the vehicle, and the core role is to buffer the impact of the driver and the passenger with the vehicle body at the moment of collision, reduce the risk of injury and death, and greatly reduce the harm to the key parts of the human body in the collision.

[0003] The structure of the airbag ignition system of the present automobile is shown in Figure 1 , which comprises a main control MCU, an ignition control chip and multiple PSI5 buses, and each PSI5 bus is connected with multiple acceleration sensors. In use, the ignition control chip first performs data interaction with the acceleration sensors through the PSI5 bus, obtains the data detected by the acceleration sensors, and stores the data in the internal storage array; then the main control MCU communicates with the ignition control chip to obtain the data in the storage array. In combination with Figure 1 , the specific use process is that the main control MCU sends a clock signal CLK to the ignition control chip, the ignition control chip performs time counting, and after the counting value reaches the set time, the ignition control chip sends a synchronization pulse to the PSI5 bus, the acceleration sensors perform data sending according to the synchronization pulse in a preset order, that is, through time division multiplexing, and also perform internal clock adjustment according to the interval of the synchronization pulse.

[0004] For the structure shown in Figure 1 , the following problems exist in use: When the clock difference between the main control MCU and the acceleration sensors is large, since all the clock adjustment is only performed in the acceleration sensors, as the working time becomes longer, the temperature changes or the aging, etc., the clock difference between the main control MCU and the acceleration sensors exceeds the range of the self-adjustment of the acceleration sensors, and the bus communication may fail; In addition, the clock following is performed by the acceleration sensors, and the differences between the acceleration sensors may cause different results of the clock adjustment, so that the acceleration sensors on the PSI5 bus cannot perform data sending according to the preset time division multiplexing time, that is, the communication conflict problem occurs, which finally leads to communication failure and cannot normally obtain the data of the acceleration sensors. SUMMARY

[0005] In view of the deficiencies in the background art, the present application provides a data synchronization method of an airbag ignition system, and the technical problem to be solved is that the existing airbag ignition control system will cause bus communication failure and cannot normally acquire sensor data of an acceleration sensor when the clock difference between a master MCU and the acceleration sensor is too large.

[0006] To solve the above technical problems, the present application provides the following technical solution: a data synchronization method of an airbag ignition system, the airbag ignition system comprising a master MCU and an ignition control chip, the master MCU performing SPI communication with the ignition control chip; the ignition control chip is connected with at least one PSI5 bus, and each PSI5 bus is connected with at least one acceleration sensor; comprising the following steps: S1: setting a preset interval of sending a synchronization pulse signal based on the clock of the master MCU and the clock of the ignition control chip; specifically as follows: the master MCU sends an initial heartbeat pulse to the ignition control chip multiple times at a set interval, and the ignition control chip counts between two adjacent initial heartbeat pulses and takes the timing value when the count value is stable as the preset interval; S2: the ignition control chip sends a synchronization pulse signal to the PSI5 bus based on the preset interval, and simultaneously sends a heartbeat pulse signal to the master MCU; the acceleration sensor on the PSI5 bus sends sensor data to the ignition control chip in a preset order after receiving the synchronization pulse signal, and adjusts its clock frequency according to the interval of the synchronization pulse signal; the ignition control chip stores the sensor data in a storage array after receiving the sensor data; the ignition control chip also calculates the time interval between adjacent two sensor data when receiving the sensor data on the same PSI5 bus, and adjusts the value of the preset interval based on the time interval; the master MCU starts timing after receiving the heartbeat pulse signal, and performs SPI communication with the ignition control chip to acquire the sensor data in the storage array after the timing time reaches a preset time; in addition, the master MCU calculates the time interval of adjacent heartbeat pulse signals when receiving the heartbeat pulse signal, and adjusts the preset time based on the time interval of adjacent heartbeat pulse signals.

[0007] In certain embodiments, in step S2, the ignition control chip sends the synchronization pulse signal by a timer, the target value of the timer is the preset interval, and the timer is reset to zero each time it reaches the preset interval.

[0008] In certain embodiments, the set interval is 250us, 500us, 750us or 1000us.

[0009] In some embodiments, the pin of the master MCU sending the initial heartbeat pulse and the pin of the ignition control chip sending the heartbeat pulse signal are electrically connected for bidirectional communication.

[0010] In some embodiments, the pin of the master MCU sending the initial heartbeat pulse and the pin of the ignition control chip sending the heartbeat pulse signal are respectively connected to ground through a pull-down resistor or to power supply through a pull-up resistor.

[0011] In some embodiments, the ignition control chip calculates the time interval between two adjacent sensor data in the following way: The ignition control chip obtains the start time and the end time of each sensor data, and calculates the time difference between the end time and the start time of two adjacent sensor data, which is the time interval.

[0012] In some embodiments, the change trend of the preset interval is negatively correlated with the time interval.

[0013] In some embodiments, the ignition control chip calculates the clock frequency of the acceleration sensor based on the start time and the end time of the sensor data on the PSI5 bus, calculates the difference value between the clock frequency of the acceleration sensor and the clock frequency of the ignition control chip, and adjusts the value of the preset interval based on the difference value.

[0014] In some embodiments, the ignition control chip adjusts the value of the preset interval based on the difference value in the following way: The original value of the preset interval is added by half of the difference value to obtain the new value of the preset interval.

[0015] In some embodiments, in step S2, the ignition control chip simultaneously sends a synchronization pulse signal to all PSI5 buses; Or the ignition control chip sends a synchronization pulse signal to all PSI5 buses in time division; at this time, the ignition control chip calculates the time interval between two adjacent sensor data when receiving the sensor data on the same PSI5 bus, and adjusts the value of the preset interval of the corresponding PSI5 bus based on the time interval.

[0016] The present application has the beneficial effect compared with the prior art: in actual use, the preset interval of the synchronization pulse signal is set based on the clock of the master MCU and the ignition control chip, then the clock frequency of the acceleration sensor on the PSI5 bus is controlled based on the preset interval, so as to remove the clock deviation of the master MCU from affecting the communication of the whole ignition system; in addition, the preset interval of the synchronization pulse signal is adjusted by monitoring the interval of the sensor data on the PSI5 bus, so as to avoid the case that the interval of the sensor data on the PSI5 bus is too short and the data is confused; finally, the data reading is performed by the master MCU through the interval of the heartbeat pulse signal, so as to ensure the integrity and real-time of the reading data. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Fig. 1 is a structural schematic diagram of the prior art airbag ignition system; Figure 2 Fig. 2 is a structural schematic diagram of the airbag ignition system of the present application in the embodiment; Figure 3 Fig. 3 is a signal waveform diagram of the bidirectional communication between the master MCU and the ignition control chip in the embodiment; Figure 4 Fig. 4 is a schematic diagram of the sensor data transmission on the PSI5 bus in the embodiment; Figure 5 Fig. 5 is a comparative schematic diagram of the sensor data interval amplification on the PSI5 bus in the embodiment. DETAILED DESCRIPTION

[0018] The illustrative embodiments of the present application include, but are not limited to, a data synchronization method of an airbag ignition system.

[0019] The exemplary embodiments will be described in detail herein below with reference to the drawings. The following description is merely illustrative of the present application and is not intended to limit the present application to the disclosed embodiments. Rather, the disclosed embodiments are intended to explain the principles of the present application to those of ordinary skill in the art. The present application is capable of achieving other objects, advantages, and features together with the disclosed embodiments, without departing from the scope of the present application.

[0020] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in this application and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "and / or," "comprises" and / or "comprising," when used in this application and the appended claims, are taken to be open-ended terms that specify the existence of the stated features, elements and / or components, but do not exclude the existence of additional features, elements and / or components. "Connected" or "coupled" and / or similar terms are not restricted to direct or physical connections or attachments, and can include electrical connection, whether direct or indirect.

[0021] In order to ensure the accuracy of the data acquisition of the airbag ignition system and the normal communication of the whole, the embodiment provides a data synchronization method of the airbag ignition system, and the structure of the airbag ignition system is as shown in Figure 2 The airbag ignition system comprises a main control MCU 1 and an ignition control chip 2, the main control MCU 1 communicates with the ignition control chip 2 through SPI and bidirectional communication, the ignition control chip 2 is connected with at least one PSI5 bus, and at least one acceleration sensor 3 is connected to each PSI5 bus. The data synchronization method comprises the following steps: S1: based on the clock of the main control MCU 1 and the clock of the ignition control chip 2, a preset interval of sending a synchronization pulse signal is set; S2: the ignition control chip 2 sends the synchronization pulse signal to the PSI5 bus based on the preset interval, and simultaneously sends a heartbeat pulse signal to the main control MCU 1; After the acceleration sensor 3 on the PSI5 bus receives the synchronization pulse signal, the acceleration sensor 3 sends sensor data to the ignition control chip 2 in a preset order, and adjusts the clock frequency of the acceleration sensor 3 according to the interval of the synchronization pulse signal; after the ignition control chip receives the sensor data, the ignition control chip stores the sensor data in a storage array; When the ignition control chip 2 receives the sensor data on the same PSI5 bus, the ignition control chip 2 also calculates the time interval between two adjacent sensor data, and adjusts the value of the preset interval based on the time interval; After the main control MCU 1 receives the heartbeat pulse signal, the main control MCU 1 starts timing, and after the timing time reaches a preset time, the main control MCU 1 communicates with the ignition control chip 2 through SPI to acquire the sensor data in the storage array; in addition, when the main control MCU 1 receives the heartbeat pulse signal, the main control MCU 1 calculates the time interval of adjacent heartbeat pulse signals, and adjusts the preset time based on the time interval of the adjacent heartbeat pulse signals.

[0022] In actual use, the preset interval of the synchronization pulse signal is first set based on the clock of the main control MCU 1 and the ignition control chip 2, and then the clock frequency of the acceleration sensor 3 on the PSI5 bus is controlled by the ignition control chip 2 based on the preset interval, so as to remove the influence of the clock deviation of the main control MCU 1 on the communication of the entire ignition system. In addition, the preset interval of the synchronization pulse signal is adjusted by the ignition control chip 2 by monitoring the interval of the sensor data on the PSI5 bus, so as to avoid the case that the interval of the sensor data on the PSI5 bus is too short and the data is chaotic. Finally, the data is read by the main control MCU 1 through the interval of the heartbeat pulse signal, so as to ensure the integrity and real-time of the read data.

[0023] For step S1 in the embodiment, it corresponds to an initialization step. Specifically, in step S1, the preset interval of the synchronization pulse signal is set based on the clock of the main control MCU 1 and the clock of the ignition control chip 2 as follows: Referring to Figure 3 The main control MCU 1 sends the initial heartbeat pulse heartbeat to the ignition control chip 2 at a set interval for multiple times, and the ignition control chip 2 counts between two adjacent initial heartbeat pulses heartbeat respectively, and takes the timing value when the counting value is stable as the preset interval. In step S2, the ignition control chip 2 sends the synchronization pulse signal by timing. The target value of the timer is the preset interval, and the timer is reset to zero after reaching the preset interval each time.

[0024] For the airbag ignition system, when it is just started, the clock of the main control MCU 1 will not immediately reach a stable state due to the influence of the power supply voltage or other factors. Therefore, the main control MCU 1 sends the initial heartbeat pulse heartbeat to the ignition control chip 2 at a set interval for multiple times, so as to ensure the accuracy of the calculated preset interval.

[0025] For example, assuming that the set interval is 500us, and the clock of the ignition control chip 2 is 20MHz, when the counting value of the ignition control chip 2 between the stable two adjacent initial heartbeat pulses heartbeat is 9800, the target value of the timer is 9800 at this time. After obtaining the preset interval, i.e., the target value of the timer, in step S2, the timer of the ignition control chip 2 sends the synchronization pulse signal to the PSI5 bus after timing to 9800 each time.

[0026] In some embodiments, the set interval and the number of the initial heartbeat pulse heartbeat sent by the main control MCU 1 can be set according to actual needs. The set interval is not necessarily 500us, but can also be 250us, 750us or 1000us. The number can be 10, 15 or 20.

[0027] in addition Figure 3 The working stage in this embodiment is equivalent to step S2 in the method of this embodiment, at which time the ignition control chip 2 starts to work; in this embodiment, by having the main control MCU1 start at different working stages from the ignition control chip 2, time-sharing drive is used to avoid signal conflicts and save resources.

[0028] Specifically, in this embodiment, the method of the present invention further includes electrically connecting the pin of the main control MCU1 that sends the initial heartbeat pulse and the pin of the ignition control chip 2 that sends the heartbeat pulse signal to perform bidirectional communication.

[0029] Furthermore, in this embodiment, the pin of the main control MCU1 that sends the initial heartbeat pulse and the pin of the ignition control chip 2 that sends the heartbeat pulse signal are respectively grounded through a pull-down resistor or connected to the power supply through a pull-up resistor.

[0030] Specifically, in this embodiment, the ignition control chip 2 calculates the time interval between two adjacent sensor data points as follows: For example, refer to Figure 4 There are four accelerometers 3 on the PSI5 bus. After the synchronization pulse signal syncpulse is sent, the time slots of the sensor data of the four accelerometers 3 are slot1, slot2, slot3 and slot4 respectively. The ignition control chip 2 obtains the start time and end time of each sensor data, and calculates the time difference between adjacent end times and start times. The time difference is the time interval GAP.

[0031] Furthermore, in this embodiment, the trend of the preset interval is negatively correlated with the time interval GAP; that is, when the time interval GAP increases, the preset interval can be reduced, thereby increasing the PSI5 bus bandwidth. A schematic diagram of sensor data transmission when the time interval GAP increases is shown below. Figure 5 As shown; When the time interval GAP becomes smaller, the preset interval can be increased. This can adjust the clock frequency of the accelerometer 3, thereby increasing the time interval GAP and ultimately preventing data transmission failure when transmitting sensor data.

[0032] Specifically, in the embodiment, the ignition control chip 2 also calculates the clock frequency of the acceleration sensor 3 based on the start time and the end time of the sensor data on the PSI5 bus, and calculates the difference value between the clock frequency of the acceleration sensor 3 and the clock frequency of the ignition control chip 2, and adjusts the value of the preset interval based on the difference value; thus, in the control process of the entire airbag ignition control system, the clock of the acceleration sensor 3 can be continuously adjusted to avoid too large clock difference between the acceleration sensor 3 and the main control MCU 1.

[0033] Further, in the embodiment, since the acceleration sensor 3 also has a clock following function, the ignition control chip 2 adjusts the value of the preset interval based on the difference value in the following manner: The original value of the preset interval is added to half of the difference value to obtain the new value of the preset interval, so that clock adjustment conflicts can be avoided.

[0034] In addition, in actual implementation, a time monitoring module 20 can be arranged in the ignition control chip 2, and the time monitoring module 20 is used to calculate the time interval between adjacent two sensor data on the PSI5 bus, calculate the clock frequency of the acceleration sensor, and calculate the difference value between the clock frequency of the acceleration sensor and the clock frequency of the main control MCU 1.

[0035] Specifically, in the embodiment, in step S2, the ignition control chip 2 simultaneously sends a synchronization pulse signal to all PSI5 buses; Or the ignition control chip sends the synchronization pulse signal to all PSI5 buses in time division; at this time, the ignition control chip 2 also calculates the time interval between adjacent two sensor data when receiving the sensor data on the same PSI5 bus, and adjusts the value of the preset interval of the corresponding PSI5 bus based on the time interval; In addition, for the main control MCU 1, the main control MCU 1 can count time according to the first sent synchronization pulse signal, and then read the stored sensor data in the ignition control chip 2 after the timing time. According to the above disclosure, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. A data synchronization method for an airbag ignition system, characterized in that, The airbag ignition system includes a main control MCU and an ignition control chip. The main control MCU communicates with the ignition control chip via SPI. The ignition control chip is connected to at least one PSI5 bus, and at least one acceleration sensor is connected to each PSI5 bus. Includes the following steps: S1: Based on the clock of the main control MCU and the clock of the ignition control chip, a preset interval for sending synchronization pulse signals is set; specifically as follows: the main control MCU sends initial heartbeat pulses to the ignition control chip multiple times at the set interval, and the ignition control chip counts between two adjacent initial heartbeat pulses, and uses the timing value when the count value is stable as the preset interval. S2: The ignition control chip sends a synchronization pulse signal to the PSI5 bus based on the preset interval, and simultaneously sends a heartbeat pulse signal to the main control MCU; After receiving the synchronization pulse signal, the accelerometer on the PSI5 bus sends sensor data to the ignition control chip in a preset order and adjusts its own clock frequency according to the interval of the synchronization pulse signal; after receiving the sensor data, the ignition control chip stores the sensor data in the storage array. When receiving sensor data from the same PSI5 bus, the ignition control chip also calculates the time interval between two adjacent sensor data and adjusts the value of the preset interval based on the time interval. After receiving the heartbeat pulse signal, the main control MCU starts timing and communicates with the ignition control chip via SPI after the timing reaches a preset time to obtain sensor data from the storage array. In addition, when the main control MCU receives the heartbeat pulse signal, it calculates the time interval between adjacent heartbeat pulse signals and adjusts the preset time based on the time interval between adjacent heartbeat pulse signals.

2. The data synchronization method for an airbag ignition system according to claim 1, characterized in that, In step S2, the ignition control chip sends a synchronization pulse signal by using a timer. The target value of the timer is the preset interval, and the timer is reset to zero each time the preset interval is reached.

3. The data synchronization method for an airbag ignition system according to claim 2, characterized in that, The set interval is 250us, 500us, 750us or 1000us.

4. The data synchronization method for an airbag ignition system according to claim 2, characterized in that, The pin that sends the initial heartbeat pulse from the main control MCU is electrically connected to the pin that sends the heartbeat pulse signal from the ignition control chip to enable bidirectional communication.

5. The data synchronization method for an airbag ignition system according to claim 2, characterized in that, The pin that sends the initial heartbeat pulse from the main control MCU and the pin that sends the heartbeat pulse signal from the ignition control chip are respectively connected to the power supply via pull-down resistors or pull-up resistors.

6. A data synchronization method for an airbag ignition system according to any one of claims 2-5, characterized in that, The ignition control chip calculates the time interval between two adjacent sensor data points as follows: The ignition control chip acquires the start and end times of each sensor data, and calculates the time difference between adjacent end and start times, where the time difference is a time interval.

7. The data synchronization method for an airbag ignition system according to claim 6, characterized in that, The trend of change of the preset interval is negatively correlated with the trend of change of the time interval.

8. The data synchronization method for an airbag ignition system according to claim 7, characterized in that, The ignition control chip calculates the clock frequency of the accelerometer based on the start and end times of the sensor data on the PSI5 bus, calculates the difference between the clock frequency of the accelerometer and the clock frequency of the ignition control chip, and adjusts the value of the preset interval based on the difference.

9. A data synchronization method for an airbag ignition system according to claim 8, characterized in that, The ignition control chip adjusts the value of the preset interval based on the difference value in the following way: The original value of the preset interval is added to half of the difference value to obtain the new value of the preset interval.

10. A data synchronization method for an airbag ignition system according to claim 9, characterized in that, In step S2, the ignition control chip simultaneously sends a synchronization pulse signal to all PSI5 buses; Alternatively, the ignition control chip may send synchronization pulse signals to all PSI5 buses in a time-sharing manner. At this time, when the ignition control chip receives sensor data on the same PSI5 bus, it also calculates the time interval between two adjacent sensor data and adjusts the value of the preset interval of the corresponding PSI5 bus based on the time interval.

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