Signal symmetry test system and method

Abstract

The application belongs to the technical field of testing, and provides a signal symmetry testing system and method. The testing system comprises a power module, an acquisition module, a wake-up module and a measured CAN transceiver module. The acquisition module is connected with the measured CAN transceiver module and the wake-up module respectively. The first power end of the power module is connected with the measured CAN transceiver module. The acquisition module, the measured CAN transceiver module and the power module are all grounded. The power module outputs a first voltage signal. The wake-up module outputs a wake-up signal and stops working after outputting the wake-up signal. The measured CAN transceiver module starts working according to the wake-up signal. The acquisition module acquires a first level signal, a second level signal and a first power supply voltage signal output by the measured CAN transceiver module under the first voltage signal, and determines a first target value according to the first level signal, the second level signal and the first power supply voltage signal. The first target value represents the symmetry of the CAN signal output by the measured CAN transceiver module.

Description

Technical Field

[0001] This application belongs to the field of testing technology, and in particular relates to a signal symmetry testing system and method. Background Technology

[0002] Currently, the networking and intelligentization of automotive control functions has become an inevitable trend in the development of the modern automotive industry. Because the CAN (Controller Area Network) bus communication protocol has abolished the traditional station address coding, the number of nodes in the CAN network is unlimited, and it has good real-time performance and high communication speed. Therefore, it is widely used in automotive electronic control systems.

[0003] To ensure the safety and stability of automotive electronic control systems, CAN signals need to be tested. One crucial test is the symmetry test of the CAN signal. CAN signal symmetry improves anti-interference capabilities, ensures communication efficiency, reduces signal reflection, and complies with relevant standards. However, existing CAN signal symmetry testing methods rely on data provided in the product manual, leading to inaccurate test results. Summary of the Invention

[0004] This application provides a signal symmetry testing system and method, which can solve the problem that the test results of existing CAN signal symmetry testing schemes are not accurate enough.

[0005] In a first aspect, embodiments of this application provide a signal symmetry testing system, including a power module, a data acquisition module, a wake-up module, and a CAN transceiver module under test. The data acquisition module is connected to the CAN transceiver module under test and the wake-up module, respectively. The first power supply terminal of the power module is connected to the CAN transceiver module under test. The data acquisition module, the CAN transceiver module under test, and the power module are all grounded.

[0006] The power supply module is used to output a first voltage signal; the wake-up module is used to output a wake-up signal and stops working after outputting the wake-up signal; the CAN transceiver module under test is used to start working according to the wake-up signal; the acquisition module is used to acquire the first level signal, the second level signal and the first power supply voltage signal output by the CAN transceiver module under test under the first voltage signal, and determine a first target value according to the first level signal, the second level signal and the first power supply voltage signal. The first target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test.

[0007] In one possible implementation of the first aspect, the power supply module is further configured to output a second voltage signal, the second voltage signal being less than the first voltage signal; the acquisition module is further configured to acquire a third level signal, a fourth level signal, and a second power supply voltage signal output by the CAN transceiver module under test under the second voltage signal, and determine a second target value based on the third level signal, the fourth level signal, and the second power supply voltage signal, the second target value being used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test.

[0008] In one possible implementation of the first aspect, the power supply module is further configured to output a third voltage signal, the third voltage signal being greater than the first voltage signal; the acquisition module is further configured to acquire the fifth level signal, the sixth level signal, and the third power supply voltage signal output by the CAN transceiver module under test under the third voltage signal, and determine a third target value based on the fifth level signal, the sixth level signal, and the third power supply voltage signal, the third target value being used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test.

[0009] In one possible implementation of the first aspect, the second power supply terminal of the power module is connected to the CAN transceiver module under test;

[0010] The power module is also used to output a fourth voltage signal; the CAN transceiver module under test is also used to start working according to the fourth voltage signal.

[0011] In one possible implementation of the first aspect, the wake-up module includes a wake-up unit and a first resistor, the first resistor being connected in parallel with the wake-up unit; or, the signal symmetry test system further includes a second resistor, the second resistor being connected in parallel with the first resistor.

[0012] Secondly, embodiments of this application provide a signal symmetry testing method, including:

[0013] Apply a first voltage signal to the CAN transceiver module under test;

[0014] The CAN transceiver module under test acquires a wake-up signal and starts working according to the wake-up signal;

[0015] The first level signal, the second level signal, and the first power supply voltage signal output by the CAN transceiver module under test are collected under the first voltage signal.

[0016] A first target value is determined based on the first level signal, the second level signal, and the first power supply voltage signal. The first target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test.

[0017] In one possible implementation of the second aspect, the signal symmetry testing method further includes:

[0018] A second voltage signal is applied to the CAN transceiver module under test, the second voltage signal being less than the first voltage signal;

[0019] The third level signal, the fourth level signal, and the second power supply voltage signal output by the CAN transceiver module under test are collected under the second voltage signal.

[0020] The second target value is determined based on the third level signal, the fourth level signal, and the second power supply voltage signal. The second target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test.

[0021] In one possible implementation of the second aspect, the signal symmetry testing method further includes:

[0022] A third voltage signal is applied to the CAN transceiver module under test, the third voltage signal being greater than the first voltage signal;

[0023] The fifth level signal, the sixth level signal, and the third power supply voltage signal output by the CAN transceiver module under test are collected under the third voltage signal.

[0024] A third target value is determined based on the fifth level signal, the sixth level signal, and the third power supply voltage signal. The third target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test.

[0025] In one possible implementation of the second aspect, the acquisition of the first level signal, the second level signal, and the first power supply voltage signal output by the CAN transceiver module under the first voltage signal includes:

[0026] Waiting for the preset time;

[0027] When the waiting time reaches the preset time, the first level signal, the second level signal, and the first power supply voltage signal output by the CAN transceiver module under test are collected when the CAN transceiver module under test is under the first voltage signal and the CAN transceiver module under test is in the message transmission interval.

[0028] In one possible implementation of the second aspect, determining the first target value based on the first level signal, the second level signal, and the first supply voltage signal includes:

[0029] The sum of the first level signal and the second level signal is calculated to obtain the seventh level signal;

[0030] The first target value is obtained by calculating the quotient of the seventh level signal and the first power supply voltage signal.

[0031] The beneficial effects of the embodiments in this application compared with the prior art are:

[0032] This application provides a signal symmetry testing system, including a power module, a data acquisition module, a wake-up module, and a CAN transceiver module under test. The data acquisition module is connected to both the CAN transceiver module under test and the wake-up module. The first power supply terminal of the power module is connected to the CAN transceiver module under test. The data acquisition module, the CAN transceiver module under test, and the power module are all grounded.

[0033] The power supply module outputs a first voltage signal. The wake-up module outputs a wake-up signal and stops operating after outputting the wake-up signal. The CAN transceiver module under test starts operating based on the wake-up signal. The acquisition module acquires the first level signal, the second level signal, and the first supply voltage signal output by the CAN transceiver module under test under the first voltage signal, and determines a first target value based on the first level signal, the second level signal, and the first supply voltage signal. The first target value characterizes the symmetry of the CAN signal output by the CAN transceiver module under test.

[0034] The signal symmetry testing system provided in this application collects signals related to CAN signal symmetry in real time: a first level signal, a second level signal, and a first power supply voltage signal. Based on the real-time collected signals, it determines whether the CAN signal meets the symmetry requirements. Compared with existing solutions that test based on data provided in the product manual, this application improves the accuracy and reliability of CAN signal symmetry testing.

[0035] It is understandable that the beneficial effects of the second aspect mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the CAN-H and CAN-L signals on the CAN bus;

[0038] Figure 2 This is a schematic block diagram of a signal symmetry testing system provided in an embodiment of this application;

[0039] Figure 3 This is a pin diagram of a CAN transceiver chip;

[0040] Figure 4 This is a schematic block diagram of a signal symmetry testing system provided in another embodiment of this application;

[0041] Figure 5 This is a schematic block diagram of a signal symmetry testing system provided in another embodiment of this application;

[0042] Figure 6 This is a schematic block diagram of a signal symmetry testing system provided in another embodiment of this application;

[0043] Figure 7 This is a flowchart of a signal symmetry testing method provided in an embodiment of this application;

[0044] Figure 8 This is a flowchart of a signal symmetry testing method provided in another embodiment of this application;

[0045] Figure 9 This is a flowchart of a signal symmetry testing method provided in another embodiment of this application;

[0046] Figure 10 This is a flowchart of a signal symmetry testing method provided in another embodiment of this application;

[0047] Figure 11 This is a flowchart of a signal symmetry testing method provided in another embodiment of this application.

[0048] In the diagram: 10, power module; 20, acquisition module; 30, wake-up module; 31, wake-up unit; 40, CAN transceiver module under test. Detailed Implementation

[0049] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0050] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0051] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0052] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [the described condition or event] is detected," or "in response to detection of [the described condition or event]."

[0053] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0054] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0055] Figure 1 This diagram illustrates the CAN-H and CAN-L signals on a CAN bus. The symmetry of CAN signals refers to the relative symmetry of the durations of the high-level signal CAN-H (logic 1) and the low-level signal CAN-L (logic 0) on the CAN bus. Ideally, the durations of the high-level signal CAN-H and the low-level signal CAN-L should be approximately equal. The symmetry of CAN signals is usually measured by Vsym, which is an important characteristic of CAN signals. Where Vsym = (V... CAN_H +V CAN_L ) / V CC , where V CAN_H and V CAN_L These are the high-level and low-level signals of the CAN bus, V CC This is the power supply voltage for the CAN transceiver chip.

[0056] The importance of symmetry in CAN signals is mainly due to the following points: 1. Improved anti-interference capability: Symmetrical signals help resist common-mode interference and maintain correct signal interpretation. 2. Guaranteed communication efficiency: Symmetrical signals ensure that nodes can correctly interpret and identify data. 3. Reduced reflection: Symmetrical signals can reduce signal reflections caused by asymmetry. 4. Standard compliance: According to standards such as ISO 11898, symmetry is an important parameter.

[0057] As can be seen from the above, it is essential to test the symmetry of CAN signals. However, existing CAN signal symmetry testing methods rely on data provided in the product manual, resulting in inaccurate test results.

[0058] To address the aforementioned problems, embodiments of this application provide a signal symmetry testing system, such as... Figure 2 As shown, the signal symmetry test system includes a power supply module 10, an acquisition module 20, a wake-up module 30, and a CAN transceiver module under test 40. The acquisition module 20 is connected to the CAN transceiver module under test 40 and the wake-up module 30, respectively. The first power supply terminal P1 of the power supply module 10 is connected to the CAN transceiver module under test 40. The acquisition module 20, the CAN transceiver module under test 40, and the power supply module 10 are all used for grounding.

[0059] Specifically, the power supply module 10 outputs a first voltage signal to power the CAN transceiver module 40 under test. The first voltage signal is the normal power supply voltage signal Vnormal of the CAN transceiver module 40 under test. For example, the normal power supply voltage signal is the power supply voltage signal of the entire vehicle. The wake-up module 30 outputs a wake-up signal and stops working after outputting the wake-up signal to avoid affecting the CAN signal output by the CAN transceiver module 40 under test during the test. The CAN transceiver module 40 under test starts working according to the wake-up signal. The acquisition module 20 acquires the first level signal, the second level signal, and the first power supply voltage signal output by the CAN transceiver module 40 under the first voltage signal, and determines a first target value Vsym1 based on the first level signal, the second level signal, and the first power supply voltage signal. The first target value Vsym1 characterizes the symmetry of the CAN signal output by the CAN transceiver module 40 under test. After calculating the first target value Vsym1, it can be determined whether the CAN signal meets the symmetry requirements according to the signal symmetry rating index table 1.

[0060] Table 1. Evaluation Indicators for Signal Symmetry

[0061] parameter symbol Minimum value nominal value Maximum value Symmetry of CAN signals <![CDATA[V sym ]]> 0.9 1.0 1.1

[0062] In this design, the first level signal is the high-level signal CAN-H, the second level signal is the low-level signal CAN-L, and the first power supply voltage signal is the power supply voltage signal of the CAN transceiver chip in the CAN transceiver module 40 under test. It should be noted that the CAN transceiver module 40 under test is an integrated module, which includes various chips and their peripheral circuits. The test in this application is for the CAN transceiver chip in the CAN transceiver module 40 under test. The pin diagram of the CAN transceiver chip is shown below. Figure 3 As shown, the acquisition module 20 is connected to pins 6, 7, and 3 of the CAN transceiver chip, respectively, to acquire the high-level signal CAN-H, the low-level signal CAN-L, and the power supply voltage signal V. CC .

[0063] The signal symmetry testing system provided in this application collects signals related to CAN signal symmetry in real time: a first level signal, a second level signal, and a first power supply voltage signal. Based on the real-time collected signals, it determines whether the CAN signal meets the symmetry requirements. Compared with existing solutions that test based on data provided in the product manual, this application improves the accuracy and reliability of CAN signal symmetry testing.

[0064] In some embodiments, the supply voltage of the CAN transceiver module 40 under test is a range. In actual use, the normal supply voltage Vnormal is generally used to power the CAN transceiver module 40 under test. However, due to the influence of the internal circuitry and components of the CAN transceiver module 40 under test, when the supply voltage of the CAN transceiver module 40 under test is at a critical value, i.e., the maximum supply voltage and the minimum supply voltage, it may affect the supply voltage of the CAN transceiver chip in the CAN transceiver module 40 under test. Therefore, in order to further ensure the accuracy of the test, this application will change the supply voltage of the CAN transceiver module 40 under test and collect the high-level signal CAN-H, the low-level signal CAN-L, and the supply voltage signal VCC output by the CAN transceiver module 40 under test at different supply voltages to determine whether the CAN signal meets the symmetry requirements.

[0065] The power supply module 10 is also used to output a second voltage signal to power the CAN transceiver module 40 under test. The second voltage signal is lower than the first voltage signal and is the minimum supply voltage signal of the CAN transceiver module 40 under test. For example, the second voltage signal is 7V. The acquisition module 20 is also used to acquire the third level signal, the fourth level signal, and the second supply voltage signal output by the CAN transceiver module 40 under the second voltage signal, and to determine a second target value Vsym2 based on the third level signal, the fourth level signal, and the second supply voltage signal. The second target value Vsym2 is used to characterize the symmetry of the CAN signal output by the CAN transceiver module 40 under test. The third level signal is a high-level signal CAN-H, the fourth level signal is a low-level signal CAN-L, and the second supply voltage signal is the supply voltage signal of the CAN transceiver chip in the CAN transceiver module 40 under test. This application, by testing the symmetry of the CAN signal output by the CAN transceiver module 40 under test at the minimum supply voltage, can further ensure the transmission and reception capabilities of the CAN transceiver module 40 under test.

[0066] The power supply module 10 is also used to output a third voltage signal to power the CAN transceiver module 40 under test. The third voltage signal is greater than the first voltage signal and is the maximum supply voltage signal of the CAN transceiver module 40 under test. For example, the third voltage signal is 18V. The acquisition module 20 is also used to acquire the fifth level signal, the sixth level signal, and the third supply voltage signal output by the CAN transceiver module 40 under the third voltage signal, and to determine a third target value Vsym3 based on these signals. The third target value Vsym3 is used to characterize the symmetry of the CAN signal output by the CAN transceiver module 40 under test. The fifth level signal is a high-level signal CAN-H, the sixth level signal is a low-level signal CAN-L, and the third supply voltage signal is the supply voltage signal of the CAN transceiver chip in the CAN transceiver module 40 under test. This application, by testing the symmetry of the CAN signal output by the CAN transceiver module 40 under test at the maximum supply voltage, can further ensure the transmission and reception capabilities of the CAN transceiver module 40 under test.

[0067] In some embodiments, such as Figure 4 As shown, the second power supply terminal P2 of the power supply module 10 is connected to the CAN transceiver module 40 under test.

[0068] Specifically, power module 10 is also used to output a fourth voltage signal. The CAN transceiver module 40 under test is also used to start operating based on the fourth voltage signal. During actual testing, a suitable wake-up method can be selected based on the specific type of the CAN transceiver module 40 under test. When the CAN transceiver module 40 under test can only be woken up using a wake-up signal, the wake-up signal output by wake-up module 30 is used. When the CAN transceiver module 40 under test can only be woken up using the power supply signal output by power module 10, i.e., the fourth voltage signal, the fourth voltage signal is used.

[0069] In some embodiments, to ensure the stability and reliability of CAN signal transmission, the terminating resistor on the CAN bus needs to meet certain requirements, for example, the resistance value of the terminating resistor on the CAN bus is 60Ω. To achieve the requirement of a 60Ω terminating resistor on the CAN bus, such as... Figure 5 As shown, the wake-up module 30 in this application includes a wake-up unit 31 and a first resistor R1, which is connected in parallel with the wake-up unit 31. In this case, the CAN transceiver module 40 under test includes a built-in resistor, and the resistance of the first resistor R1 connected in parallel with the built-in resistor is 60Ω. Therefore, the resistance of both the first resistor R1 and the built-in resistor is 120Ω. When the CAN transceiver module 40 under test does not include a built-in resistor, such as... Figure 6 As shown, the signal symmetry test system also includes a second resistor R2, which is connected in parallel with the first resistor R1. The resistance of the first resistor R1 and the second resistor R2 in parallel is 60Ω, so the resistance of both the first resistor R1 and the second resistor R2 is 120Ω. In actual testing, a suitable circuit can be selected for testing according to the specific type of the CAN transceiver module 40 under test.

[0070] For example, the power module 10 can be a programmable power supply, but this application does not limit it to this, as long as it can output different power supply voltages.

[0071] For example, the acquisition module 20 can be an oscilloscope, but this application does not limit it to this, as long as it can output the above functions.

[0072] It should be noted that when the acquisition module 20 acquires signals, it should acquire the signal output by the CAN transceiver module 40 under test when it is in the message transmission interval, and only one CAN frame needs to be acquired. In addition, before acquisition, a certain period of time should be waited, for example, 5 seconds, to ensure the stable communication of the CAN transceiver module 40 under test.

[0073] Additionally, it should be noted that, to further ensure test stability during actual testing, it is recommended to perform 5 consecutive tests. If any test fails to meet the symmetry requirement, the test is considered a failure. The acquisition module 20 has a storage function, which can save the data and waveforms of each test.

[0074] In summary, the signal symmetry testing system provided in this application embodiment acquires in real time the high-level signal CAN-H, the low-level signal CAN-L, and the power supply voltage V of the CAN transceiver chip output by the CAN transceiver module 40 under test. CC And based on the real-time acquisition of the high-level signal CAN-H, the low-level signal CAN-L, and the power supply voltage V of the CAN transceiver chip. CC Calculating Vsym to determine whether the CAN signal meets the symmetry requirements improves the accuracy and reliability of the test.

[0075] This application also provides a method for testing signal symmetry, such as... Figure 7 As shown, it includes steps S701-S704.

[0076] S701. Apply the first voltage signal to the CAN transceiver module under test.

[0077] Specifically, a first voltage signal is applied to the CAN transceiver module under test via the power supply module to supply power to the CAN transceiver module under test. The first voltage signal is the normal power supply voltage signal Vnormal of the CAN transceiver module 40 under test.

[0078] S702, the CAN transceiver module under test obtains the wake-up signal and starts working according to the wake-up signal.

[0079] Specifically, the CAN transceiver module under test obtains a wake-up signal from the wake-up module and starts working based on the wake-up signal. It should be noted that the wake-up module stops working after outputting the wake-up signal to avoid affecting the CAN signal output by the CAN transceiver module under test during the test.

[0080] S703: Collect the first level signal, the second level signal, and the first power supply voltage signal output by the CAN transceiver module under the first voltage signal.

[0081] Specifically, the acquisition module acquires the first level signal, the second level signal, and the first power supply voltage signal output by the CAN transceiver module under test under the first voltage signal. The first level signal is a high-level signal (CAN-H), the second level signal is a low-level signal (CAN-L), and the first power supply voltage signal is the power supply voltage signal of the CAN transceiver chip in the CAN transceiver module 40 under test.

[0082] S704. Determine a first target value based on the first level signal, the second level signal, and the first power supply voltage signal. The first target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test.

[0083] Specifically, the acquisition module calculates the first target value Vsym1 based on the high-level signal CAN-H and the low-level signal CAN-L output by the CAN transceiver module under the first voltage signal and the power supply voltage signal of the CAN transceiver chip in the CAN transceiver module 40 under the test. Then, it determines the symmetry of the CAN signal output by the CAN transceiver module under the test based on the first target value Vsym1.

[0084] In summary, the signal symmetry testing method provided in this application provides real-time acquisition of the high-level signal CAN-H, the low-level signal CAN-L, and the power supply voltage V of the CAN transceiver chip output by the CAN transceiver module under test. CC And based on the real-time acquisition of the high-level signal CAN-H, the low-level signal CAN-L, and the power supply voltage V of the CAN transceiver chip. CC Calculating Vsym to determine whether the CAN signal meets the symmetry requirements improves the accuracy and reliability of the test.

[0085] In some embodiments, the supply voltage of the CAN transceiver module under test is a range. In practical use, the normal supply voltage Vnormal is generally used to power the CAN transceiver module under test. However, due to the influence of the internal circuitry and components of the CAN transceiver module under test, when the supply voltage of the CAN transceiver module under test is at a critical value, i.e., the maximum supply voltage and the minimum supply voltage, it may affect the supply voltage of the CAN transceiver chip inside the CAN transceiver module under test. Therefore, in order to further ensure the accuracy of the test, this application changes the supply voltage of the CAN transceiver module under test and collects the high-level signal CAN-H, the low-level signal CAN-L, and the supply voltage signal VCC output by the CAN transceiver module under test under different supply voltages to determine whether the CAN signal meets the symmetry requirements.

[0086] like Figure 8 As shown in the embodiment of this application, the signal symmetry testing method further includes steps S705-S707.

[0087] S705. Apply a second voltage signal to the CAN transceiver module under test. The second voltage signal is less than the first voltage signal.

[0088] Specifically, a second voltage signal is applied to the CAN transceiver module under test via the power supply module. This second voltage signal is the minimum supply voltage signal of the CAN transceiver module under test. For example, the second voltage signal is 7V.

[0089] S706: Acquire the third-level signal, fourth-level signal, and second power supply voltage signal output by the CAN transceiver module under the second voltage signal.

[0090] Specifically, the acquisition module acquires the third-level signal, the fourth-level signal, and the second power supply voltage signal output by the CAN transceiver module under the second voltage signal. The third-level signal is a high-level signal (CAN-H), the fourth-level signal is a low-level signal (CAN-L), and the second power supply voltage signal is the power supply voltage signal of the CAN transceiver chip in the CAN transceiver module under the test.

[0091] It should be noted that in step S706, before acquiring the signal, the signal output by the CAN transceiver module under test when it is in the message transmission interval should be acquired, and only one CAN frame needs to be acquired. Additionally, a certain period of time should be waited before acquisition, for example, 5 seconds, to ensure the communication stability of the CAN transceiver module under test.

[0092] S707. Determine the second target value based on the third level signal, the fourth level signal, and the second power supply voltage signal. The second target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test.

[0093] Specifically, the acquisition module calculates the second target value Vsym2 based on the high-level signal CAN-H and the low-level signal CAN-L output by the CAN transceiver module under the second voltage signal and the power supply voltage signal of the CAN transceiver chip in the CAN transceiver module 40 under the test. Then, it determines the symmetry of the CAN signal output by the CAN transceiver module under the test based on the second target value Vsym2.

[0094] This application further ensures the transmission and reception capabilities of the CAN transceiver module by testing the symmetry of the CAN signal output by the CAN transceiver module under test at the minimum supply voltage.

[0095] like Figure 9 As shown in the embodiment of this application, the signal symmetry testing method further includes steps S708-S7010.

[0096] S708. Apply a third voltage signal to the CAN transceiver module under test. The third voltage signal is greater than the first voltage signal.

[0097] Specifically, a third voltage signal is applied to the CAN transceiver module under test via the power supply module. This third voltage signal is the maximum supply voltage signal of the CAN transceiver module under test. For example, the third voltage signal is 18V.

[0098] S709: Acquire the fifth level signal, sixth level signal, and third power supply voltage signal output by the CAN transceiver module under test under the third voltage signal.

[0099] Specifically, the acquisition module acquires the fifth-level signal, the sixth-level signal, and the third power supply voltage signal output by the CAN transceiver module under test under the third voltage signal. Among them, the fifth-level signal is the high-level signal CAN-H, the sixth-level signal is the low-level signal CAN-L, and the third power supply voltage signal is the power supply voltage signal of the CAN transceiver chip in the CAN transceiver module 40 under test.

[0100] It should be noted that in step S709, before acquiring the signal, the signal output by the CAN transceiver module under test when it is in the message transmission interval should be acquired, and only one CAN frame needs to be acquired. Additionally, a certain period of time should be waited before acquisition, for example, 5 seconds, to ensure the communication stability of the CAN transceiver module under test.

[0101] S7010. Determine the third target value based on the fifth level signal, the sixth level signal, and the third power supply voltage signal. The third target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test.

[0102] Specifically, the acquisition module calculates the third target value Vsym3 based on the high-level signal CAN-H and the low-level signal CAN-L output by the CAN transceiver module under the third voltage signal and the power supply voltage signal of the CAN transceiver chip in the CAN transceiver module 40 under the test. Then, it determines the symmetry of the CAN signal output by the CAN transceiver module under the test based on the third target value Vsym3.

[0103] This application further ensures the transmission and reception capabilities of the CAN transceiver module by testing the symmetry of the CAN signal output by the CAN transceiver module under test at the maximum supply voltage.

[0104] In some embodiments, such as Figure 10 As shown, step S703 includes steps S7031-S7032.

[0105] S7031, Wait for preset time.

[0106] Specifically, to ensure stable communication of the CAN transceiver module under test, a preset time should be waited before data acquisition. For example, the preset time is 5 seconds.

[0107] S7032. When the waiting time reaches the preset time, the first level signal, the second level signal, and the first power supply voltage signal output by the CAN transceiver module under test are collected when the CAN transceiver module under test is under the first voltage signal and is in the message transmission interval.

[0108] Specifically, when collecting signals from the CAN transceiver module under test, the signal output by the CAN transceiver module under test should be collected when it is in the message transmission interval, and only one CAN frame needs to be collected.

[0109] In some embodiments, such as Figure 11 As shown, step S704 includes steps S7041-S7042.

[0110] S7041. Calculate the sum of the first level signal and the second level signal to obtain the seventh level signal.

[0111] Specifically, the first and second level signals are substituted into the first calculation formula to obtain the seventh level signal. The first calculation formula is:

[0112] V7 = V1 + V2;

[0113] Wherein, V1 is the first level signal, V2 is the second level signal, and V7 is the seventh level signal.

[0114] S7042. Calculate the quotient of the seventh level signal and the first power supply voltage signal to obtain the first target value.

[0115] Specifically, the seventh-level signal and the first supply voltage signal are substituted into the second calculation formula to obtain the first target value. The second calculation formula is:

[0116] Vsym1 = V7 / Vcc1;

[0117] Where Vsym1 is the first target value and Vcc1 is the first power supply voltage signal.

[0118] In summary, the signal symmetry testing method provided in this application provides real-time acquisition of the high-level signal CAN-H, the low-level signal CAN-L, and the power supply voltage V of the CAN transceiver chip output by the CAN transceiver module under test. CC And based on the real-time acquisition of the high-level signal CAN-H, the low-level signal CAN-L, and the power supply voltage V of the CAN transceiver chip. CC Calculating Vsym to determine whether the CAN signal meets the symmetry requirements improves the accuracy and reliability of the test.

[0119] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0120] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A signal symmetry testing system, characterized in that, It includes a power module, a data acquisition module, a wake-up module, and a CAN transceiver module under test. The data acquisition module is connected to the CAN transceiver module under test and the wake-up module, respectively. The first power supply terminal of the power module is connected to the CAN transceiver module under test. The data acquisition module, the CAN transceiver module under test, and the power module are all grounded. The power supply module is used to output a first voltage signal; the wake-up module is used to output a wake-up signal and stops working after outputting the wake-up signal; the CAN transceiver module under test is used to start working according to the wake-up signal; the acquisition module is used to acquire the first level signal, the second level signal, and the first power supply voltage signal output by the CAN transceiver module under test under the first voltage signal, and determine a first target value according to the first level signal, the second level signal, and the first power supply voltage signal. The first target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test; the first level signal is a high level signal, and the second level signal is a low level signal.

2. The signal symmetry testing system according to claim 1, characterized in that, The power supply module is also used to output a second voltage signal, which is less than the first voltage signal; the acquisition module is also used to acquire the third level signal, the fourth level signal, and the second power supply voltage signal output by the CAN transceiver module under test under the second voltage signal, and to determine a second target value based on the third level signal, the fourth level signal, and the second power supply voltage signal. The second target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test; the third level signal is a high level signal, and the fourth level signal is a low level signal.

3. The signal symmetry testing system according to claim 1, characterized in that, The power supply module is also used to output a third voltage signal, which is greater than the first voltage signal; the acquisition module is also used to acquire the fifth level signal, the sixth level signal, and the third power supply voltage signal output by the CAN transceiver module under test under the third voltage signal, and to determine a third target value based on the fifth level signal, the sixth level signal, and the third power supply voltage signal. The third target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test; the fifth level signal is a high level signal, and the sixth level signal is a low level signal.

4. The signal symmetry testing system according to any one of claims 1-3, characterized in that, The second power supply terminal of the power module is connected to the CAN transceiver module under test. The power module is also used to output a fourth voltage signal; the CAN transceiver module under test is also used to start working according to the fourth voltage signal.

5. The signal symmetry testing system according to any one of claims 1-3, characterized in that, The wake-up module includes a wake-up unit and a first resistor, the first resistor being connected in parallel with the wake-up unit; or, the signal symmetry test system further includes a second resistor, the second resistor being connected in parallel with the first resistor.

6. A method for testing signal symmetry, characterized in that, include: Apply a first voltage signal to the CAN transceiver module under test; The CAN transceiver module under test acquires a wake-up signal and starts working according to the wake-up signal; The first level signal, the second level signal, and the first power supply voltage signal output by the CAN transceiver module under test are collected under the first voltage signal. A first target value is determined based on the first level signal, the second level signal, and the first power supply voltage signal. The first target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test. The first level signal is a high level signal, and the second level signal is a low level signal.

7. The signal symmetry testing method according to claim 6, characterized in that, The signal symmetry testing method further includes: A second voltage signal is applied to the CAN transceiver module under test, the second voltage signal being less than the first voltage signal; The third level signal, the fourth level signal, and the second power supply voltage signal output by the CAN transceiver module under test are collected under the second voltage signal. A second target value is determined based on the third level signal, the fourth level signal, and the second power supply voltage signal. The second target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test. The third level signal is a high level signal, and the fourth level signal is a low level signal.

8. The signal symmetry testing method according to claim 6, characterized in that, The signal symmetry testing method further includes: A third voltage signal is applied to the CAN transceiver module under test, the third voltage signal being greater than the first voltage signal; The fifth level signal, the sixth level signal, and the third power supply voltage signal output by the CAN transceiver module under test are collected under the third voltage signal. A third target value is determined based on the fifth level signal, the sixth level signal, and the third power supply voltage signal. The third target value is used to characterize the symmetry of the CAN signal output by the CAN transceiver module under test. The fifth level signal is a high level signal, and the sixth level signal is a low level signal.

9. The signal symmetry testing method according to any one of claims 6-8, characterized in that, The acquisition of the first level signal, second level signal, and first power supply voltage signal output by the CAN transceiver module under test under the first voltage signal includes: Waiting for the preset time; When the waiting time reaches the preset time, the first level signal, the second level signal, and the first power supply voltage signal output by the CAN transceiver module under test are collected when the CAN transceiver module under test is under the first voltage signal and the CAN transceiver module under test is in the message transmission interval.

10. The signal symmetry testing method according to claim 6, characterized in that, Determining the first target value based on the first level signal, the second level signal, and the first power supply voltage signal includes: The sum of the first level signal and the second level signal is calculated to obtain the seventh level signal; The first target value is obtained by calculating the quotient of the seventh level signal and the first power supply voltage signal.

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