CN115996156B - Bus network system and impedance matching method thereof - Google Patents
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- CN115996156B CN115996156B CN202310273848.0A CN202310273848A CN115996156B CN 115996156 B CN115996156 B CN 115996156B CN 202310273848 A CN202310273848 A CN 202310273848A CN 115996156 B CN115996156 B CN 115996156B
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Abstract
The invention discloses a bus network system and an impedance matching method thereof, wherein the bus network system comprises at least one bus network device, each bus network device comprises an input interface, an output interface and an impedance matching unit, and the impedance matching method comprises the following steps: identifying whether the input interface is connected with the output interfaces of other bus network devices or not to obtain a first identification signal, and identifying whether the output interface is connected with the input interfaces of other bus network devices or not to obtain a second identification signal; and controlling the impedance matching unit according to the first identification signal and the second identification signal so as to automatically match the impedance of the bus network system. The method judges the access position of the bus network equipment by identifying whether the input interface is connected with other bus network equipment and the output interface is connected with other bus network equipment, thereby realizing the automatic control of impedance matching according to the access position of the bus network equipment.
Description
Technical Field
The present disclosure relates to the field of communications technologies, and in particular, to a bus network system and an impedance matching method thereof.
Background
CAN (control area network) is a small-sized local area network communication technology, and is widely applied to the fields of automobile manufacturing, industrial control, consumer electronics and the like. The CAN bus network requires two communication lines, CANH and CANL, respectively. When the cable is longer or the speed is higher, the CAN bus needs to be impedance matched, as shown in fig. 1, and two ends of the CAN bus are generally connected with a 120 Ω resistor respectively.
Currently, in the field of instruments, the terminated 120Ω resistor is typically embedded inside the instrument. When an instrument is newly added in the CAN bus, since the 120Ω resistor is generally disposed at two ends of the CAN bus, a user needs to determine whether to enable the internal terminating 120Ω resistor according to the position where the instrument is connected, and the method of enabling or closing the terminating resistor is generally implemented as a dial switch or by controlling a switch through an internal main control unit, which requires intervention of an operator, so that the method is not intelligent enough.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, a first object of the present invention is to provide an impedance matching method of a bus network system, which is capable of automatically controlling impedance matching according to an access position of a bus network device by identifying whether an input interface is connected with other bus network devices and an output interface is connected with other bus network devices.
A second object of the present invention is to propose a bus network system.
To achieve the above object, according to a first aspect of the present invention, there is provided an impedance matching method of a bus network system including at least one bus network device, each bus network device including an input interface, an output interface, and an impedance matching unit, the method including: identifying whether the input interface is connected with the output interfaces of other bus network devices or not to obtain a first identification signal, and identifying whether the output interface is connected with the input interfaces of other bus network devices or not to obtain a second identification signal; and controlling the impedance matching unit according to the first identification signal and the second identification signal so as to automatically match the impedance of the bus network system.
According to the impedance matching method of the bus network system, whether the input interface is connected with the output interfaces of other bus network devices is identified to obtain a first identification signal, whether the output interface is connected with the input interfaces of the other bus network devices is identified to obtain a second identification signal, and the impedance matching unit is controlled according to the first identification signal and the second identification signal to enable the bus network system to perform automatic impedance matching, wherein the bus network system comprises at least one bus network device, and each bus network device comprises the input interface, the output interface and the impedance matching unit. Therefore, when the input interface is connected with other bus network equipment and the output interface is connected with other bus network equipment, the bus network equipment is positioned at the middle position without impedance matching control, and when the input interface is connected with other bus network equipment or the output interface is connected with other bus network equipment, the bus network equipment is positioned at the two ends and impedance matching control is required, so that the position where the bus network equipment is accessed can be judged according to the connection state of the input interface and the output interface, and the automatic control of impedance matching is performed according to the position where the bus network equipment is accessed, the intervention of a main control unit and an operator in a system is not required, and the automation level of the bus network is improved.
According to an embodiment of the present invention, an impedance matching unit includes an impedance adjusting section connected between a first bus line and a second bus line, wherein the impedance matching unit is controlled according to a first identification signal and a second identification signal, including: when the input interface is determined to be connected with the output interface of the other bus network device according to the first identification signal and the input interface is determined to be connected with the input interface of the other bus network device according to the second identification signal, the impedance adjusting part is controlled to be disconnected from the first bus and the second bus.
According to one embodiment of the invention, the input interface comprises: the first terminal is suitable for being connected with a first bus, the second terminal is suitable for being connected with a second bus, the third terminal is suitable for being connected with a fifth terminal in an output interface of other bus network equipment and is respectively connected with a first input end of the impedance matching unit and one end of the first resistor, the other end of the first resistor is connected with a preset power supply, and the fourth terminal is suitable for being connected with a sixth terminal in the output interface of other bus network equipment and is connected with ground; the output interface comprises: the system comprises a second resistor, a fifth terminal, a sixth terminal, a seventh terminal and an eighth terminal, wherein the seventh terminal is suitable for being connected with a first bus, the eighth terminal is suitable for being connected with a second bus, the sixth terminal is suitable for being connected with a fourth terminal in an input interface of other bus network equipment, the sixth terminal is respectively connected with a second input end of an impedance matching unit and one end of the second resistor, the other end of the second resistor is connected with a preset power supply, the fifth terminal is suitable for being connected with a third terminal in the input interface of other bus network equipment, and the fifth terminal is connected with ground, and when the input interface is connected with an output interface of other bus network equipment, a first identification signal is a low-level signal; when the output interface is connected with the input interfaces of other bus network devices, the second identification signal is a low-level signal.
To achieve the above object, according to a second aspect of the present invention, there is provided a bus network system including at least one bus network device, each bus network device including an input interface, an output interface, and an impedance matching unit, wherein the impedance matching unit is connected to the input interface and the output interface, respectively, the impedance matching unit is configured to identify whether the input interface is connected to the output interfaces of other bus network devices to obtain a first identification signal, and to identify whether the output interface is connected to the input interfaces of the other bus network devices to obtain a second identification signal, and to perform impedance matching control according to the first identification signal and the second identification signal, so that the bus network system performs automatic impedance matching.
According to the bus network system provided by the embodiment of the invention, the access position of the bus network equipment is judged by identifying whether other bus network equipment is connected to the input interface and whether other bus network equipment is connected to the output interface, so that the automatic control of impedance matching is realized according to the access position of the bus network equipment.
According to one embodiment of the invention, the input interface comprises: the first terminal is suitable for being connected with a first bus, the second terminal is suitable for being connected with a second bus, the third terminal is suitable for being connected with a fifth terminal in an output interface of other bus network equipment and is respectively connected with a first input end of the impedance matching unit and one end of the first resistor, the other end of the first resistor is connected with a preset power supply, and the fourth terminal is suitable for being connected with a sixth terminal in the output interface of other bus network equipment and is connected with ground.
According to one embodiment of the invention, the output interface comprises: the system comprises a second resistor, a fifth terminal, a sixth terminal, a seventh terminal and an eighth terminal, wherein the seventh terminal is suitable for being connected with a first bus, the eighth terminal is suitable for being connected with a second bus, the sixth terminal is suitable for being connected with a fourth terminal in an input interface of other bus network equipment and is respectively connected with a second input end of an impedance matching unit and one end of the second resistor, the other end of the second resistor is connected with a preset power supply, and the fifth terminal is suitable for being connected with a third terminal in the input interface of other bus network equipment and is connected with ground.
According to one embodiment of the invention, the first identification signal is a low level signal when the input interface is connected to the output interface of the other bus network device; when the output interface is connected with the input interfaces of other bus network devices, the second identification signal is a low-level signal.
According to an embodiment of the present invention, an impedance matching unit includes: an impedance adjusting section connected between the first bus and the second bus; and a drive control section connected to the impedance adjusting section, the drive control section being configured to control the impedance adjusting section to be disconnected from between the first bus and the second bus when both the first identification signal and the second identification signal are low-level signals.
According to one embodiment of the invention, the impedance adjusting section comprises a third resistor and a controllable switch connected in series.
According to an embodiment of the present invention, a drive control section includes: the first input pin of the OR gate is used as a first input end of the impedance matching unit, the second input pin of the OR gate is used as a second input end of the impedance matching unit, and the OR gate outputs a removal control signal when the first identification signal and the second identification signal are low-level signals; the input end of the driver is connected with the output end of the OR gate, the output end of the driver is connected with the control end of the controllable switch, and the driver drives the controllable switch to be disconnected when receiving the removal control signal so as to remove the third resistor from between the first bus and the second bus.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a system diagram of a bus network system in the related art;
FIG. 2 is a system diagram of a bus network system according to one embodiment of the invention;
FIG. 3 is a flow chart of a method of impedance matching for a bus network system according to one embodiment of the invention;
fig. 4 is a circuit diagram of an impedance matching unit according to an embodiment of the present invention;
fig. 5 is a circuit diagram of a bus network system according to one embodiment of the invention.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
The bus network system and the impedance matching method thereof according to the embodiment of the present invention are described below with reference to the accompanying drawings.
Fig. 2 is a system diagram of a bus network system according to one embodiment of the invention. As shown in fig. 2, the bus network system 200 includes at least one bus network device 100, and each bus network device 100 includes an input interface 10, an output interface 20, and an impedance matching unit 30.
Wherein the input interface 10 is adapted to connect to the output interface 20 of other bus network devices 100; the output interface 20 is adapted to connect to the input interface 10 of other bus network devices 100; the impedance matching unit 30 is connected to the input interface 10 and the output interface 20, respectively.
Fig. 3 is a flow chart of an impedance matching method of a bus network system according to an embodiment of the present invention. As shown in fig. 3, the impedance matching method includes:
s101, identifying whether the input interface is connected with the output interfaces of other bus network devices to obtain a first identification signal, and identifying whether the output interface is connected with the input interfaces of other bus network devices to obtain a second identification signal.
Specifically, when the input interface is connected with other bus network devices and the output interface is connected with other bus network devices, other bus network devices are arranged on two sides of the bus network devices, so that the bus network devices are positioned in the middle position, and impedance matching control is not needed; when the input interface is connected with other bus network equipment and the output interface is not connected with other bus network equipment, the bus network equipment is positioned at the tail end and impedance matching control is needed; when the input interface is not connected with other bus network devices and the output interface is connected with other bus network devices, the bus network devices are at the front end, and impedance matching control is needed.
S102, controlling the impedance matching unit according to the first identification signal and the second identification signal so as to enable the bus network system to perform automatic impedance matching.
Specifically, the first identification signal is generated according to the connection state of the input interface, and the second identification signal is generated according to the connection state of the output interface, so that the position where the bus network device is accessed can be judged according to the first identification signal and the second identification signal, and the automatic control of impedance matching is performed according to the position where the bus network device is accessed.
In the above embodiment, the connection state of the input interface and the output interface can be used to determine the access position of the bus network device, and the impedance matching is automatically controlled according to the access position of the bus network device, so that the intervention of a main control unit and an operator in the system is not required, and the automation level of the bus network is improved.
In some embodiments, as shown in fig. 4, the impedance matching unit 30 includes an impedance adjusting section 31, the impedance adjusting section 31 being connected between a first bus CANH and a second bus CANL, wherein controlling the impedance matching unit according to a first identification signal and a second identification signal includes: when the input interface is determined to be connected with the output interface of the other bus network device according to the first identification signal and the input interface is determined to be connected with the input interface of the other bus network device according to the second identification signal, the impedance adjusting part is controlled to be disconnected from the first bus and the second bus.
Specifically, the impedance adjusting portion is disposed between the first bus and the second bus, so that the impedance can be connected to the bus network when impedance matching is required, and the impedance matching of the impedance adjusting portion is removed when it is recognized that other bus network devices are connected to the input interface and other bus network devices are connected to the output interface, that is, when the bus network devices are in the intermediate position.
In some embodiments, as shown in fig. 5, the input interface 10 includes: a first resistor R1, a first terminal I1, a second terminal I2, a third terminal I3 and a fourth terminal I4, wherein the first terminal I1 is adapted to be connected to a first bus CANH, the second terminal I2 is adapted to be connected to a second bus CANL, the third terminal I3 is adapted to be connected to a fifth terminal I5 in the output interface 20 of the other bus network device 100 and to be connected to a first input of the impedance matching unit 30 and to one end of the first resistor R1, respectively, the other end of the first resistor R1 is connected to a preset power supply VDD, and the fourth terminal I4 is adapted to be connected to a sixth terminal I6 in the output interface 20 of the other bus network device 100 and to ground; the output interface 20 includes: a second resistor R2, a fifth terminal I5, a sixth terminal I6, a seventh terminal I7 and an eighth terminal I8, wherein the seventh terminal I7 is adapted to be connected to the first bus CANH, the eighth terminal I8 is adapted to be connected to the second bus CANL, the sixth terminal I6 is adapted to be connected to the fourth terminal I4 in the input interface 10 of the other bus network device 100 and to be connected to the second input of the impedance matching unit 30 and to one end of the second resistor R2, respectively, the other end of the second resistor R2 is connected to a preset power supply VDD, the fifth terminal I5 is adapted to be connected to the third terminal I3 in the input interface 10 of the other bus network device 100 and to ground, wherein the first identification signal is a low level signal when the input interface 10 is connected to the output interface 20 of the other bus network device 100; when the input interface 10 of the other bus network device 100 is connected to the output interface 20, the second identification signal is a low level signal.
Specifically, the bus network has two buses, namely, a first bus CANH and a second bus CANL, and the voltage values of the first bus CANH and the second bus CANL are different, so that the first bus CANH and the second bus CANL generate differential signals, thereby realizing signal transmission. The first resistor R1 is disposed between the preset power supply VDD and the third terminal I3, and when the third terminal I3 is not connected to the other bus network device 100, the first resistor R1 pulls up the electrical signal of the third terminal I3 to a high level, the electrical signal of the third terminal I3 is a high level, and the first identification signal is a high level signal; the third terminal I3 is connected to the fifth terminal I5 in the output interface 20 of the other bus network device 100, and the electrical signal of the third terminal I3 is pulled down to a low level by the fifth terminal I5 in the output interface 20 of the other bus network device 100, and the electrical signal of the third terminal I3 is a low level signal and the first identification signal is a low level signal. The second resistor R2 is disposed between the preset power supply VDD and the sixth terminal I6, and the sixth terminal I6 pulls up the signal of the sixth terminal I6 to a high level when no other bus network device 100 is connected to the sixth terminal I6, the electrical signal of the sixth terminal I6 is a high level, and the second identification signal is a high level signal; the sixth terminal I6 is connected to the fourth terminal I4 in the output interface 20 of the other bus network device 100, and the electrical signal of the sixth terminal I6 is pulled down to a low level by the fourth terminal I4 in the output interface 20 of the other bus network device 100, and the electrical signal of the sixth terminal I6 is a low level signal and the second identification signal is a low level signal.
Further, since the input interface 10 and the output interface 20 each include four terminals, the cable connecting each bus network device 100 is a multi-core cable including at least four cores.
In the above-described embodiment, when the other bus network device is connected to the third terminal, the electrical signal of the third terminal is caused to change from the high level to the low level, and therefore, whether the other bus network device is connected to the input interface can be determined by the electrical signal of the third terminal; when the other bus network device is connected to the sixth terminal, the electrical signal of the sixth terminal is changed from the high level to the low level, and therefore, whether the other bus network device is connected to the input interface can be determined by the electrical signal of the sixth terminal.
In summary, according to the impedance matching method of the bus network system in the embodiment of the present invention, when it is identified that the input interface is connected with other bus network devices and the output interface is connected with other bus network devices, the bus network devices are located at the middle position, impedance matching control is not required, when it is identified that the input interface is connected with other bus network devices or the output interface is connected with other bus network devices, the bus network devices are located at the two ends, impedance matching control is required, therefore, the connection state of the input interface and the output interface can determine the position where the bus network devices are connected, and automatic control of impedance matching is performed according to the position where the bus network devices are connected, intervention of a master control unit and an operator in the system is not required, and automation level of the bus network is improved.
Corresponding to the above embodiment, the embodiment of the present invention further provides a bus network system. As shown in fig. 2, the bus network system 200 includes at least one bus network device 100, each bus network device 100 includes an input interface 10, an output interface 20, and an impedance matching unit 30, wherein the impedance matching unit 30 is connected to the input interface 10 and the output interface 20, respectively, the impedance matching unit 30 is configured to recognize whether the input interface 10 is connected to the output interface 20 of the other bus network device 100 to obtain a first recognition signal, and recognize whether the output interface 20 is connected to the input interface 10 of the other bus network device 100 to obtain a second recognition signal, and perform impedance matching control according to the first recognition signal and the second recognition signal to automatically impedance match the bus network system 200.
In some embodiments, the input interface 10 includes: a first resistor R1, a first terminal I1, a second terminal I2, a third terminal I3 and a fourth terminal I4, wherein the first terminal I1 is adapted to be connected to a first bus CANH, the second terminal I2 is adapted to be connected to a second bus CANL, the third terminal I3 is adapted to be connected to a fifth terminal I5 in the output interface 20 of the other bus network device 100 and to be connected to a first input of the impedance matching unit 30 and to one end of the first resistor R1, respectively, the other end of the first resistor R1 is connected to a preset power supply VDD, and the fourth terminal I4 is adapted to be connected to a sixth terminal I6 in the output interface 20 of the other bus network device 100 and to ground.
Specifically, the bus network has two buses, namely, a first bus CANH and a second bus CANL, and the voltage values of the first bus CANH and the second bus CANL are different, so that the first bus CANH and the second bus CANL generate differential signals, thereby realizing signal transmission. The first resistor R1 is disposed between the preset power supply VDD and the third terminal I3, and when the third terminal I3 is not connected to the other bus network device 100, the first resistor R1 pulls up the electrical signal of the third terminal I3 to a high level, the electrical signal of the third terminal I3 is a high level, and the first identification signal is a high level signal; the third terminal I3 is connected to the fifth terminal I5 in the output interface 20 of the other bus network device 100, and the electrical signal of the third terminal I3 is pulled down to a low level by the fifth terminal I5 in the output interface 20 of the other bus network device 100, and the electrical signal of the third terminal I3 is a low level signal and the first identification signal is a low level signal.
In the above-described embodiment, when the other bus network device is connected to the third terminal, the electric signal of the third terminal is caused to change from the high level to the low level, and therefore, whether or not the other bus network device is connected to the input interface can be determined by the electric signal of the third terminal.
In some embodiments, output interface 20 comprises: a second resistor R2, a fifth terminal I5, a sixth terminal I6, a seventh terminal I7 and an eighth terminal I8, wherein the seventh terminal I7 is adapted to be connected to the first bus CANH, the eighth terminal I8 is adapted to be connected to the second bus CANL, the sixth terminal I6 is adapted to be connected to the fourth terminal I4 in the input interface 10 of the other bus network device 100 and to be connected to the second input of the impedance matching unit 30 and to one end of the second resistor R2, respectively, the other end of the second resistor R2 is connected to a preset power supply VDD, and the fifth terminal I5 is adapted to be connected to the third terminal I3 in the input interface 10 of the other bus network device 100 and to ground.
Specifically, the second resistor R2 is disposed between the preset power supply VDD and the sixth terminal I6, and the sixth terminal I6 pulls up the signal of the sixth terminal I6 to a high level when the other bus network device 100 is not connected, the electrical signal of the sixth terminal I6 is a high level, and the second identification signal is a high level signal; the sixth terminal I6 is connected to the fourth terminal I4 in the output interface 20 of the other bus network device 100, and the electrical signal of the sixth terminal I6 is pulled down to a low level by the fourth terminal I4 in the output interface 20 of the other bus network device 100, and the electrical signal of the sixth terminal I6 is a low level signal and the second identification signal is a low level signal.
Further, since the input interface 10 and the output interface 20 each include four terminals, the cable connecting each bus network device 100 is a multi-core cable including at least four cores.
In the above-described embodiment, when the other bus network device is connected to the sixth terminal, the electrical signal of the sixth terminal is caused to change from the high level to the low level, and therefore, whether or not the other bus network device is connected to the input interface can be determined by the electrical signal of the sixth terminal.
In some embodiments, the first identification signal is a low level signal when the input interface 10 is connected to the output interface 20 of the other bus network device 100; when the input interface 10 of the other bus network device 100 is connected to the output interface 20, the second identification signal is a low level signal.
Referring to the above analysis, when the input interface 10 is connected to the output interface 20 of the other bus network device 100, the first identification signal is pulled down to a low level signal; when the input interface 10 of the other bus network device 100 is connected to the output interface 20, the second identification signal is pulled down to a low level signal.
In some embodiments, the impedance matching unit 30 includes: an impedance adjusting section 31 and a drive control section 32, wherein the impedance adjusting section 31 is connected between the first bus CANH and the second bus CANL; the drive control section 32 is connected to the impedance adjusting section 31, and the drive control section 32 is configured to control the impedance adjusting section 31 to be disconnected from between the first bus line and the second bus line when both the first identification signal and the second identification signal are low-level signals.
Specifically, the impedance adjusting section 31 is provided between the first bus CANH and the second bus CANL so that the impedance can be connected to the bus network when impedance matching is required, and the drive control section 32 removes the impedance matching of the impedance adjusting section 31 when it is recognized that the input interface 10 is connected to the other bus network device 100 and the output interface 20 is connected to the other bus network device 100, that is, when the bus network device 100 is in the neutral position.
In some embodiments, the impedance adjusting section 31 includes a third resistor R3 and a controllable switch S connected in series.
That is, by controlling the switching state of the controllable switch S, whether or not impedance matching is performed can be controlled. When the controllable switch S is turned off, the third resistor R3 is not connected to the bus network; when the controllable switch S is closed, the third resistor R3 is connected to the bus network for impedance matching.
In an alternative embodiment, the controllable switch S is a normally closed switch.
It will be appreciated that the controllable switch S is in a closed state by default, i.e. impedance matching is performed by default, so as to ensure that signals on the bus network can be normally transmitted when the bus network device 100 is accessed.
It should be noted that the controllable switch S may be an analog switch, a relay, or other on-off devices, which is not limited herein.
In some embodiments, the drive control section 32 includes: an OR gate OR and driver 321, wherein a first input pin of the OR gate OR is used as a first input terminal of the impedance matching unit 30, a second input pin of the OR gate OR is used as a second input terminal of the impedance matching unit 30, and the OR gate OR outputs a removal control signal when the first identification signal and the second identification signal are both low level signals; an input terminal of the driver 321 is connected to an output terminal of the OR gate OR, an output terminal of the driver 321 is connected to a control terminal of the controllable switch S, and the driver 321 drives the controllable switch S to be turned off when receiving the removal control signal, so that the third resistor R3 is removed from between the first bus CANH and the second bus CANL.
Specifically, when the other bus network device 100 is connected to the third terminal I3, the third terminal I3 is low, the first identification signal is a low signal, and when the other bus network device 100 is connected to the sixth terminal I6, the sixth terminal I6 is low, and the second identification signal is a low signal, so that the OR gate OR outputs a low signal when receiving the first identification signal and the second identification signal at the same time, the driver 321 controls the controllable switch S to be turned off so that the third resistor R3 is removed from between the first bus CANH and the second bus CANL, thereby achieving the removal impedance matching. When the first identification signal OR the second identification signal is at a high level, the OR gate OR outputs a high level signal, and the driver 321 controls the controllable switch S to be closed, so that the third resistor R3 is connected between the first bus CANH and the second bus CANL, thereby realizing impedance matching.
In summary, according to the bus network system of the embodiment of the present invention, by identifying whether the input interface is connected with other bus network devices and the output interface is connected with other bus network devices, the position where the bus network devices are accessed is determined, so that automatic control of impedance matching is implemented according to the position where the bus network devices are accessed.
It should be noted that the logic and/or steps represented in the flowcharts or otherwise described herein, for example, may be considered as a ordered listing of executable instructions for implementing logical functions, and may be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). In addition, the computer readable medium may even be paper or other suitable medium on which the program is printed, as the program may be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.
It is to be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Furthermore, the terms "first," "second," and the like, as used in embodiments of the present invention, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or as implying any particular number of features in the present embodiment. Thus, a feature of an embodiment of the invention that is defined by terms such as "first," "second," etc., may explicitly or implicitly indicate that at least one such feature is included in the embodiment. In the description of the present invention, the word "plurality" means at least two or more, for example, two, three, four, etc., unless explicitly defined otherwise in the embodiments.
In the present invention, unless explicitly stated or limited otherwise in the examples, the terms "mounted," "connected," and "fixed" as used in the examples should be interpreted broadly, e.g., the connection may be a fixed connection, may be a removable connection, or may be integral, and it may be understood that the connection may also be a mechanical connection, an electrical connection, etc.; of course, it may be directly connected, or indirectly connected through an intermediate medium, or may be in communication with each other, or in interaction with each other. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific embodiments.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.
Claims (6)
1. A method of impedance matching of a bus network system, the bus network system comprising at least one bus network device, each bus network device comprising an input interface, an output interface and an impedance matching unit, the method comprising:
identifying whether the input interface is connected with output interfaces of other bus network devices or not to obtain a first identification signal, and identifying whether the output interface is connected with the input interfaces of other bus network devices or not to obtain a second identification signal;
controlling the impedance matching unit according to the first identification signal and the second identification signal so as to automatically match the impedance of the bus network system;
the input interface includes: a first resistor, a first terminal, a second terminal, a third terminal and a fourth terminal, wherein the first terminal is suitable for being connected with a first bus, the second terminal is suitable for being connected with a second bus, the third terminal is suitable for being connected with a fifth terminal in an output interface of other bus network equipment, and is respectively connected with a first input end of the impedance matching unit and one end of the first resistor, the other end of the first resistor is connected with a preset power supply, and the fourth terminal is suitable for being connected with a sixth terminal in an output interface of other bus network equipment and is connected with ground; the output interface includes: a second resistor, a fifth terminal, a sixth terminal, a seventh terminal and an eighth terminal, wherein the seventh terminal is adapted to be connected to the first bus, the eighth terminal is adapted to be connected to the second bus, the sixth terminal is adapted to be connected to a fourth terminal in an input interface of another bus network device and to a second input of the impedance matching unit and one end of the second resistor, respectively, the other end of the second resistor is connected to a preset power supply, the fifth terminal is adapted to be connected to a third terminal in an input interface of another bus network device and to ground, wherein,
when the input interface is connected with output interfaces of other bus network devices, the first identification signal is a low-level signal;
when the output interface is connected with the input interfaces of other bus network devices, the second identification signal is a low-level signal.
2. The impedance matching method of the bus network system according to claim 1, wherein the impedance matching unit includes an impedance adjusting section connected between a first bus and a second bus, wherein controlling the impedance matching unit according to the first identification signal and the second identification signal includes:
and when the output interface is determined to be connected with the output interface of other bus network equipment according to the first identification signal and the input interface is determined to be connected with the input interface of other bus network equipment according to the second identification signal, the impedance adjusting part is controlled to be disconnected from the first bus and the second bus.
3. A bus network system comprising at least one bus network device, each of said bus network devices comprising an input interface, an output interface and an impedance matching unit, wherein,
the impedance matching unit is respectively connected with the input interface and the output interface, and is configured to identify whether the input interface is connected with output interfaces of other bus network devices or not so as to obtain a first identification signal, identify whether the output interface is connected with the input interfaces of other bus network devices or not so as to obtain a second identification signal, and perform impedance matching control according to the first identification signal and the second identification signal so as to enable the bus network system to perform automatic impedance matching;
the input interface includes: a first resistor, a first terminal, a second terminal, a third terminal and a fourth terminal, wherein the first terminal is suitable for being connected with a first bus, the second terminal is suitable for being connected with a second bus, the third terminal is suitable for being connected with a fifth terminal in an output interface of other bus network equipment, and is respectively connected with a first input end of the impedance matching unit and one end of the first resistor, the other end of the first resistor is connected with a preset power supply, and the fourth terminal is suitable for being connected with a sixth terminal in an output interface of other bus network equipment and is connected with ground;
the output interface includes: a second resistor, a fifth terminal, a sixth terminal, a seventh terminal and an eighth terminal, wherein the seventh terminal is suitable for being connected with the first bus, the eighth terminal is suitable for being connected with the second bus, the sixth terminal is suitable for being connected with a fourth terminal in an input interface of other bus network equipment, and is respectively connected with a second input end of the impedance matching unit and one end of the second resistor, the other end of the second resistor is connected with a preset power supply, and the fifth terminal is suitable for being connected with a third terminal in an input interface of other bus network equipment and is connected with ground;
when the input interface is connected with output interfaces of other bus network devices, the first identification signal is a low-level signal; when the output interface is connected with the input interfaces of other bus network devices, the second identification signal is a low-level signal.
4. A bus network system according to claim 3, wherein the impedance matching unit comprises:
an impedance adjusting section connected between the first bus and the second bus;
and a drive control section connected to the impedance adjusting section, the drive control section being configured to control the impedance adjusting section to be disconnected from between the first bus and the second bus when the first identification signal and the second identification signal are both low-level signals.
5. The bus network system as set forth in claim 4, wherein the impedance adjusting section comprises a third resistor and a controllable switch connected in series.
6. The bus network system according to claim 5, wherein the drive control section includes:
the first input pin of the OR gate is used as a first input end of the impedance matching unit, the second input pin of the OR gate is used as a second input end of the impedance matching unit, and the OR gate outputs a removal control signal when the first identification signal and the second identification signal are low-level signals;
the input end of the driver is connected with the output end of the OR gate, the output end of the driver is connected with the control end of the controllable switch, and the driver drives the controllable switch to be disconnected when receiving the removal control signal so as to remove the third resistor from between the first bus and the second bus.
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Address after: 230088 floor 1-4, zone a, building E2, phase II, innovation industrial park, No. 2800, innovation Avenue, high tech Zone, Hefei, Anhui Province Patentee after: Guoyi Quantum Technology (Hefei) Co.,Ltd. Patentee after: Beijing Guoyi Precision Measurement Technology Co.,Ltd. Address before: 230088 floor 1-4, zone a, building E2, phase II, innovation industrial park, No. 2800, innovation Avenue, high tech Zone, Hefei, Anhui Province Patentee before: Guoyi Quantum (Hefei) Technology Co.,Ltd. Patentee before: Beijing Guoyi Precision Measurement Technology Co.,Ltd. |