WO2022040996A1 - 板内通信电路及板内通信装置 - Google Patents
板内通信电路及板内通信装置 Download PDFInfo
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- WO2022040996A1 WO2022040996A1 PCT/CN2020/111502 CN2020111502W WO2022040996A1 WO 2022040996 A1 WO2022040996 A1 WO 2022040996A1 CN 2020111502 W CN2020111502 W CN 2020111502W WO 2022040996 A1 WO2022040996 A1 WO 2022040996A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
Definitions
- the present application relates to the technical field of electronic circuits, and in particular, to an intra-board communication circuit and an intra-board communication device.
- the controller area network (CAN) bus is a multi-master bus, that is, each node machine can become the master, and the node machines can also communicate.
- CAN communication is widely used in automotive, medical, marine, aviation and other fields due to its excellent performance, unique design and high reliability.
- In-board communication generally adopts serial communication interface (SCI), serial peripheral interface (SPI), I2C (inter-integrated circuit, built-in integrated circuit) and other buses, but CAN bus has its own There are some advantages, the use of CAN bus for intra-board communication can make full use of its advantages to realize the communication process in different scenarios.
- SCI serial communication interface
- SPI serial peripheral interface
- I2C inter-integrated circuit, built-in integrated circuit
- CAN bus has its own
- SCI serial communication interface
- SPI serial peripheral interface
- I2C inter-integrated circuit, built-in integrated circuit
- Embodiments of the present application provide an intra-board communication circuit and an intra-board communication device, which implement CAN communication in the board without using a CAN transceiver, thereby reducing hardware costs.
- an intra-board communication circuit is provided.
- the intra-board communication circuit is used to implement intra-board communication between a first communication node and a second communication node, and the intra-board communication circuit includes a first communication node. a diode, a second diode and a first resistor, wherein:
- the transmitting end of the first communication node is connected to the cathode of the first diode, the anode of the first diode is connected to the receiving end of the first communication node; the transmitting end of the second communication node is connected to The cathode of the second diode, the anode of the second diode is connected to the receiving end of the second communication node; the first end of the first resistor is connected to the anode of the first diode, The second end of the first resistor is connected to the first power supply end; if the receiving end of the first communication node is connected to the receiving end of the second communication node, if the transmitting end of the first communication node and the The transmitting end of the second communication node is both high level, and the on-board communication circuit realizes that the receiving end of the first communication node and the receiving end of the second communication node are both high level.
- the on-board communication circuit implements the receiving end of the first communication node and the The receiving end of the second communication node is all low level.
- the on-board communication circuit further includes a second resistor, the first end of the second resistor is connected to the anode of the second diode, and the second end of the second resistor is connected to the second power terminal , the power supply level of the first power supply terminal and the second power supply terminal is the same;
- the receiving end of the first communication node is connected to the transmitting end of the second communication node, and the transmitting end of the first communication node is connected to the receiving end of the second communication node, if the first communication The transmitting end of the node is low level or the transmitting end of the second communication node is low level, and the on-board communication circuit realizes that both the receiving end of the first communication node and the receiving end of the second communication node are to low level.
- the on-board communication circuit further includes a first filter circuit; the anode of the first diode is connected to the receiving end of the first communication node through the first filter circuit.
- the first filter circuit includes a third resistor and a first capacitor; the first end of the first capacitor is connected to the first end of the third resistor and the receiving end of the first communication node, so The second end of the first capacitor is connected to the first ground end, and the second end of the third resistor is connected to the anode of the first diode.
- the in-board communication circuit further includes a second filter circuit; the anode of the second diode is connected to the receiving end of the second communication node through the second filter circuit.
- the second filter circuit includes a fourth resistor and a second capacitor; the first end of the second capacitor is connected to the second end of the fourth resistor and the receiving end of the second communication node, so The second end of the second capacitor is connected to the second ground end, and the first end of the fourth resistor is connected to the anode of the second diode.
- an intra-board communication device in a second aspect of the embodiments of the present application, includes a first communication node, a second communication node, and any one of the intra-board communication circuits in the first aspect of the embodiments of the present application .
- ground terminals of the first communication node and the second communication node are connected to the same ground terminal.
- both the first communication node and the second communication node include a microcontroller unit and a CAN controller.
- both the first communication node and the second communication node include a micro-control unit, and a CAN controller is integrated in the micro-control unit.
- the power supply terminal of the first communication node is connected to the first auxiliary power supply, and the power supply terminal of the second communication node is connected to the second auxiliary power supply.
- the embodiments of the present application provide an in-board communication circuit, which includes a first diode, a second diode and a first resistor.
- the in-board communication circuit has a simple structure and few electronic components.
- the on-board communication circuit can realize the receiving end of the first communication node and the second communication node.
- the receiving ends of the communication nodes are all high-level, so that the CAN communication on the board is realized without the need of the CAN transceiver, and the hardware cost is reduced.
- 1a is a schematic diagram of CAN communication using a CAN transceiver in a traditional method
- Fig. 1b is a signal schematic diagram of CAN communication realized by the on-board communication circuit disclosed in the embodiment of the present application;
- Fig. 1c is the level schematic diagram of CAN communication realized by the on-board communication circuit disclosed in the embodiment of the present application;
- FIG. 2a is a schematic structural diagram of an in-board communication circuit disclosed in an embodiment of the present application.
- 2b is a schematic structural diagram of another on-board communication circuit disclosed in an embodiment of the present application.
- FIG. 3 is a schematic structural diagram of another on-board communication circuit disclosed in an embodiment of the present application.
- FIG. 4 is a schematic structural diagram of an in-board communication device disclosed in an embodiment of the present application.
- FIG. 5 is a schematic structural diagram of another in-board communication device disclosed in an embodiment of the present application.
- each communication node sends and receives signals from other communication nodes on the bus through a CAN transceiver. Therefore, each communication node must add a CAN transceiver. In addition, a CAN controller is required to implement CAN communication.
- FIG. 1a is a schematic diagram of CAN communication using a CAN transceiver in the conventional method.
- the CAN controller is integrated inside the microcontroller unit MCU.
- the CAN controller can receive the data sent by the microprocessor in the microcontroller unit MCU, and transmit the data to the CAN transceiver; the CAN transceiver is used to transmit data to the bus or receive data from the bus and transmit it to the CAN controller.
- MCU microcontroller unit
- adding a CAN transceiver to each communication node will increase the cost of the on-board communication.
- FIG. 1 b is a schematic diagram of a CAN signal using a CAN transceiver to realize CAN communication disclosed in an embodiment of the present application.
- Fig. 1b is a schematic diagram of CAN signals in CAN communication using a CAN transceiver based on Fig. 1a.
- the CAN signal is a bit stream signal that alternates with dominant level and recessive level.
- the CAN signal can include transmission control commands, and can also include data segments or data blocks.
- "0" represents dominant, dominant corresponds to low level
- "1" represents recessive
- recessive corresponds to high level.
- the CAN signal takes the control command as an example.
- the CAN signal is the dominant level "0" in the first time period, the recessive level “1” in the second time period, and the third time period.
- the dominant level is “0” in the time period
- the dominant level is “0” in the fourth time period
- the recessive level "1” is in the fifth time period.
- the sum of the durations is used as a cycle, and the levels corresponding to the five time periods will appear repeatedly in the next cycle, which can be used to periodically transmit the same control command.
- FIG. 1c is a schematic level diagram of a CAN signal using a CAN transceiver to implement CAN communication disclosed in an embodiment of the present application.
- FIG. 1c is a schematic diagram of the level of CAN signals in CAN communication using a CAN transceiver based on FIG. 1a.
- the dominant level and the recessive level in the CAN signal are not voltages corresponding to two specific values, but correspond to two voltage ranges.
- the dominant level in the CAN signal is "0V ⁇ 1.5V”, the corresponding recessive level is "1.5V ⁇ 5V”; when the dominant level in the CAN signal is "0V ⁇ 2.5V”, the corresponding recessive level is "2.5V ⁇ 5V”; When the dominant level in the CAN signal is "0V ⁇ 3.5V”, the corresponding recessive level is "3.5V ⁇ 5V”.
- the embodiments of the present application provide an intra-board communication circuit and an intra-board communication device, which can implement CAN communication in the board without using a CAN transceiver. A detailed description will be given below.
- FIG. 2a is a schematic structural diagram of an on-board communication circuit disclosed in an embodiment of the present application.
- the intra-board communication circuit 30 described in this embodiment is used to realize intra-board communication between the first communication node 10 and the second communication node 20, and the intra-board communication circuit includes a first diode D1 , the second diode D2 and the first resistor R1, where:
- the transmitting end TX1 of the first communication node 10 is connected to the cathode of the first diode D1, the anode of the first diode D1 is connected to the receiving end RX1 of the first communication node 10; the transmitting end TX2 of the second communication node 20 is connected to the second communication node 10.
- the cathode of the diode D2, the anode of the second diode D2 is connected to the receiving end RX2 of the second communication node 20; the first end of the first resistor R1 is connected to the anode of the first diode D1, and the first end of the first resistor R1 is connected to the anode of the first diode D1.
- the two terminals are connected to the first power terminal;
- the receiving end RX1 of the first communication node 10 is connected to the receiving end RX2 of the second communication node 20 if both the transmitting end TX1 of the first communication node 10 and the transmitting end TX2 of the second communication node 20 are at a high level,
- the on-board communication circuit 30 realizes that both the receiving end RX1 of the first communication node 10 and the receiving end RX2 of the second communication node 20 are at a high level;
- the on-board communication circuit 30 realizes the reception of the first communication node 10 Both the terminal RX1 and the receiving terminal RX2 of the second communication node 20 are at low level.
- the on-board communication circuit 30 in the embodiment of the present application is suitable for the case where both the first communication node and the second communication node can output a high level or a low level.
- the transmitting end TX1 of the first communication node 10 when the transmitting end TX1 of the first communication node 10 is at a high level and the transmitting end TX2 of the second communication node 20 is at a high level, the first diode in the on-board communication circuit 30 D1 is non-conducting, and the second diode D2 is non-conducting.
- the receiving end RX1 of the first communication node 10 and the receiving end RX2 of the second communication node 20 are controlled by the high level of the first power supply terminal, and both are high level;
- the transmitting terminal TX1 of the first communication node 10 When the transmitting terminal TX1 of the first communication node 10 is at a low level and the transmitting terminal TX2 of the second communication node 20 is at a low level, the first diode D1 and the second diode in the in-board communication circuit 30 Both the tubes D2 are turned on. Since the voltage drop of the first diode D1 and the second diode D2 is only a few tenths of a volt when the first diode D1 and the second diode D2 are conducting forward, the receiving end RX1 of the first communication node 10 and the second communication node 20 The receiving end RX2 is all low level;
- the transmitting terminal TX1 of the first communication node 10 When the transmitting terminal TX1 of the first communication node 10 is at a low level and the transmitting terminal TX2 of the second communication node 20 is at a high level, the first diode D1 in the on-board communication circuit 30 is turned on, and the second The diode D2 is not conducting, and the receiving end RX1 of the first communication node 10 is at a low level at this time. Since the receiving end RX1 of the first communication node 10 and the receiving end RX2 of the second communication node 20 are connected, the second communication The receiving end RX2 of the node 20 is also low level;
- the transmitting terminal TX1 of the first communication node 10 When the transmitting terminal TX1 of the first communication node 10 is at a high level and the transmitting terminal TX2 of the second communication node 20 is at a low level, the first diode D1 in the on-board communication circuit 30 is not conducting, and the first diode D1 in the on-board communication circuit 30 is not conducting. The two diodes D2 are turned on. At this time, the receiving end RX2 of the second communication node 20 is at a low level. Since the receiving end RX1 of the first communication node 10 and the receiving end RX2 of the second communication node 20 are connected, the first communication The receiving end RX1 of the node 10 is also low level.
- the first communication node 10 and the second communication node 20 may implement the CAN bus communication of the controller area network through the on-board communication circuit 30 .
- the first communication node 10 and the second communication node 20 can perform data transmission and control command transmission through the on-board communication circuit 30 .
- first diode D1 and the second diode D2 may be implemented by using alternative circuits having diode functions (ie, unidirectional conduction and reverse cut-off functions), which are not limited in the embodiments of the present application.
- the on-board communication circuit provided by the embodiments of the present application includes a first diode, a second diode, and a first resistor, and the on-board communication circuit has a simple structure and few electronic components.
- the on-board communication circuit in the case that the transmitting end of the first communication node and the transmitting end of the second communication node are both at high level, the on-board communication circuit can realize the receiving end of the first communication node and the transmitting end of the second communication node.
- the receiving ends of the two communication nodes are all high-level, so that the CAN communication on the board is realized without the need of the CAN transceiver, and the hardware cost is reduced.
- FIG. 2b is a schematic structural diagram of another on-board communication circuit 30 disclosed in an embodiment of the present application.
- the intra-board communication circuit 30 described in this embodiment is used to realize intra-board communication between the first communication node 10 and the second communication node 20, and the intra-board communication circuit includes a first diode D1 , the second diode D2, the first resistor R1 and the second resistor R2, wherein:
- the transmitting end TX1 of the first communication node 10 is connected to the cathode of the first diode D1, the anode of the first diode D1 is connected to the receiving end RX1 of the first communication node 10; the transmitting end TX2 of the second communication node 20 is connected to the second communication node 10.
- the cathode of the diode D2, the anode of the second diode D2 is connected to the receiving end RX2 of the second communication node 20; the first end of the first resistor R1 is connected to the anode of the first diode D1, and the first end of the first resistor R1 is connected to the anode of the first diode D1.
- the two terminals are connected to the first power terminal;
- the first end of the second resistor R2 is connected to the anodes of the two diodes D2, the second end of the second resistor R2 is connected to the second power supply terminal, and the power supply between the first power supply terminal and the second power supply terminal is equal;
- the receiving end RX1 of the first communication node 10 is connected to the transmitting end TX2 of the second communication node 20, and the transmitting end TX1 of the first communication node 10 is connected to the receiving end RX2 of the second communication node 20.
- the on-board communication circuit 30 implements the first communication node
- the receiving end RX1 of 10 and the receiving end RX2 of the second communication node 20 are both low level.
- the on-board communication circuit 30 in this embodiment of the present application is suitable for the case where the first communication node 10 and the second communication node 20 can only output a low level, for example, the first communication node 10 and the second communication node 20 are both collectors
- the case of an Open Collector (OC) gate is suitable for the case where the first communication node 10 and the second communication node 20 can only output a low level, for example, the first communication node 10 and the second communication node 20 are both collectors
- OC Open Collector
- the on-board communication circuit 30 is used to implement the receiving end RX1 of the first communication node 10 and the second communication node when the transmitting end TX1 of the first communication node 10 or the transmitting end TX2 of the second communication node 20 is at a low level
- the receiver RX2 of 20 is low level
- the transmitting terminal TX1 of the first communication node 10 When the transmitting terminal TX1 of the first communication node 10 is at a low level and the transmitting terminal TX2 of the second communication node 20 is at a low level, the first diode D1 and the second diode in the in-board communication circuit 30 Both the tubes D2 are turned on, and at this time, the receiving end RX1 of the first communication node 10 and the receiving end RX2 of the second communication node 20 are both at low level.
- the first communication node 10 and the second communication node 20 may implement the CAN bus communication of the controller area network through the on-board communication circuit 30 .
- the first communication node 10 and the second communication node 20 can perform data transmission and control command transmission through the on-board communication circuit 30 .
- first diode D1 and the second diode D2 may be implemented by using alternative circuits having diode functions (ie, unidirectional conduction and reverse cut-off functions), which are not limited in the embodiments of the present application.
- the CAN bus can be used to transmit data, and can also be used to transmit control commands.
- CAN is one of the most widely used fieldbuses in the world.
- German Bosch company developed the CAN bus in order to solve the problem of data exchange between numerous control and test instruments in modern automobiles.
- CAN bus can effectively support serial communication network of distributed control or real-time control, and has the advantages of strong anti-interference and reliable use.
- distributed environmental monitoring system greenhouse environmental monitoring system, substation monitoring system, etc.
- CAN bus is a serial data communication protocol, and its communication interface (for example, the first communication node 10 and the second communication node 20) integrates the physical layer and data link layer functions of the CAN protocol, which can complete the conversion of data. Frame processing, including bit stuffing, data block coding, cyclic redundancy check, priority determination, etc. Users can develop application layer communication protocols that meet the actual needs of the system on its basis.
- One of the biggest features of the CAN protocol is that the traditional station address coding is abolished, and the communication data block coding is replaced. This method can make the number of nodes in the network theoretically unlimited, and also allow different nodes to simultaneously received the same data.
- the CAN bus is a multi-master bus, that is, each node machine can become the master, and the node machines can also communicate;
- the communication medium of CAN bus can be twisted pair, coaxial cable or optical fiber, and the communication rate can reach 1Mbps;
- the length of the data segment transmitted in the CAN bus is up to 8 bytes, which can meet the general requirements of control commands, working states and test data in the usual industrial fields. At the same time, 8 bytes will not occupy the bus for too long, thus ensuring the real-time communication;
- the CAN protocol adopts cyclic redundancy check (CRC) check and can provide corresponding error handling functions to ensure the reliability of data communication;
- CAN can work in a multi-master mode, and any node on the network can actively send information to other nodes on the bus at any time, realizing point-to-point, point-to-multipoint and global broadcasting. Send and receive data in several ways;
- (6) CAN adopts non-destructive bus arbitration technology.
- the node with low priority actively stops data transmission, while the node with high priority can continue to transmit data without being affected, saving Bus collision arbitration time.
- the master node receives field data sent by other nodes, such as field temperature, current, pressure and other parameters, the master node generates various control commands after processing, and sends the control commands to various other nodes through the CAN bus. node.
- the first resistor R1 and the second resistor R2 are pull-up resistors, and the resistance values of the first resistor R1 and the second resistor R2 may be the same or different.
- the first resistor R1 and the second resistor R2 can improve the noise tolerance of the signal at the receiving end of the communication node and enhance the anti-interference ability.
- the first diode D1 and the second diode D2 may be common switching diodes, low power consumption switching diodes, etc.
- the parameters of the first diode D1 and the second diode D2 may be the same or different.
- the on-board communication circuit can be used in a board that does not need a large cable to carry a large current, such as a printed circuit board (PCB), etc.
- the communication node can be a micro-control unit MCU, or It is a unit that interconnects the micro-control unit MCU and other electronic components, and can also be an integrated electronic device including the micro-control unit MCU.
- Table 1 is the level change between the communication nodes of the on-board communication circuit of Figures 2a and 2b.
- the high level is “1” and the low level is "0". It can be seen from Table 1 that as long as either the transmitting end (TX1 or TX2) of the first communication node and the second communication node is at a low level, the receiving end (both RX1 and RX2) of the first communication node and the second communication node is at a low level.
- the on-board communication circuit of Fig. 2a and Fig. 2b does not use the CAN transceiver of Fig. 1a and does not use the CAN signal, and can also realize the function of CAN communication.
- the high level and the low level correspond to the "1" and "0" of the digital signal, respectively. There is no intersection between the voltage range of the analog signal corresponding to the high level and the voltage range of the analog signal corresponding to the low level.
- the voltage range of the analog signal corresponding to the high level is greater than 2.5V
- the voltage range of the analog signal corresponding to the low level is 0-1.2V.
- the first diode D1 and the second diode in the in-board communication circuit 30 Both the tubes D2 are turned on, so that the receiving end RX1 of the first communication node 10 and the receiving end RX2 of the second communication node 20 are both at low level.
- the level of the first power supply terminal is preset to 3.3V
- the voltage range of the analog signal corresponding to the high level is 2.5-10V
- the voltage range of the analog signal corresponding to the low level is 0-1.2V.
- the transmission terminal TX1 of the first communication node 10 is at a low level (eg, 0V), and the transmission terminal TX2 of the second communication node 20 is at a low level (eg, 0V). Since the negative electrode of the first diode D1 is at 0V, The anode of the first diode D1 is connected to the voltage 3.3V of the first power supply terminal through the first resistor R1, and the first diode D1 is turned on. Similarly, since the cathode of the second diode D2 is 0V, and the anode of the second diode D2 is connected to the voltage 3.3V of the first power supply terminal through the first resistor R1, the second diode D1 is turned on.
- the anode of the first diode D1 and the anode of the second diode D2 are both It is 0.2-0.7V, which is a low level. Because the receiving end RX2 of the second communication node 20, the receiving end RX of the first communication node 10, the anode of the second diode D2, and the anode of the first diode D1 are connected , the receiving end RX1 of the first communication node 10 and the receiving end RX2 of the second communication node 20 are both at low level.
- the first diode D1 in the on-board communication circuit 30 is turned on, and the second The diode D2 is non-conductive, so that the receiving end RX1 of the first communication node 10 and the receiving end RX2 of the second communication node 20 are both at low level.
- the level of the first power supply terminal is preset to 3.3V
- the voltage range of the analog signal corresponding to the high level is 2.5-10V
- the voltage range of the analog signal corresponding to the low level is 0-1.2V.
- the transmission terminal TX1 of the first communication node 10 is at a low level (for example, 0V), that is, the voltage of the negative electrode 32 of the first diode D1 is “0”, and the transmission terminal TX2 of the second communication node 20 is at a high level ( For example, 5V), that is, the voltage of the cathode 42 of the second diode D2 is "5V". Since the cathode of the first diode D1 is 0V, and the anode of the first diode D1 is connected to the voltage of 3.3V at the first power supply terminal through the first resistor R1, the first diode D1 is turned on.
- 0V low level
- 5V the voltage of the cathode 42 of the second diode D2
- the voltage drop is generally 0.2-0.7V, which is a low level, and the anode voltage of the first diode D1 is 0.2-0.7V. Since the cathode of the second diode D2 is 5V, and the anode of the second diode D2 is connected to the voltage of 3.3V at the first power supply terminal through the first resistor R1, the second diode D2 is not conducting, and the second diode D2 is not conductive.
- the anode voltage of D2 is equal to the anode voltage of the first diode D1 (ie, 0.2-0.7V), which is also low level because the receiving end RX2 of the second communication node 20, the receiving end RX of the first communication node 10, the first communication node 10
- the anodes of the two diodes D2 and the anodes of the first diode D1 are connected, so the level of the receiving end RX2 of the second communication node 20 is the same as that of the receiving end RX1 of the first communication node 10 , both being low level.
- the transmitting terminal TX1 of the first communication node 10 When the transmitting terminal TX1 of the first communication node 10 is at a high level and the transmitting terminal TX2 of the second communication node 20 is at a low level, the first diode D1 in the on-board communication circuit 30 is not conducting, and the first diode D1 in the on-board communication circuit 30 is not conducting.
- the two diodes D2 are turned on, so that the receiving end RX1 of the first communication node 10 and the receiving end RX2 of the second communication node 20 are both at low level. As shown in FIG.
- the transmission terminal TX1 of the first communication node 10 is at a high level (for example, 5V), that is, the voltage of the negative electrode 32 of the first diode D1 is “5V”, and the transmission terminal TX2 of the second communication node 20 is at a low level ( For example, 0V), that is, the voltage of the cathode 42 of the second diode D2 is “0V”.
- the cathode of the second diode D2 is 0V
- the anode of the second diode D2 is connected to the voltage of 3.3V at the first power supply terminal through the first resistor R1, then the second diode D2 is turned on.
- the voltage drop is generally 0.2-0.7V
- the anode voltage of the second diode D2 is 0.2-0.7V, which is a low level.
- the cathode of the first diode D1 is 5V, and the anode of the first diode D1 is connected to the voltage of 3.3V at the first power supply terminal through the first resistor R1, the first diode D1 is non-conductive and the second diode
- the anode voltage of D2 is equal to the anode voltage of the first diode D1 (ie, 0.2 ⁇ 0.7V), which is also a low level.
- the receiving end RX1 of the first communication node 10 Since the receiving end RX2 of the second communication node 20, the receiving end RX of the first communication node 10, the anode of the second diode D2, and the anode of the first diode D1 are connected, the receiving end RX1 of the first communication node 10 The level and the level of the receiving end RX2 of the second communication node 20 are both low levels.
- the first diode D1 and the second diode D2 in the intra-board communication circuit 30 are both It is not turned on, so that the receiving end RX1 of the first communication node 10 and the receiving end RX2 of the second communication node 20 are both at a high level.
- the level of the first power supply terminal is preset to 3.3V
- the voltage range of the analog signal corresponding to the high level is 2.5-10V
- the voltage range of the analog signal corresponding to the low level is 0-1.2V.
- the transmitting end TX1 of the first communication node 10 and the transmitting end TX2 of the second communication node 20 are both at a high level (for example, 5V), that is, the voltage of the negative electrode 32 of the first diode D1 is “5V”. Similarly, The voltage of the cathode 42 of the second diode D2 is also "5V”.
- the anode of the first diode D1 is connected to the voltage 3.3V of the first power supply terminal through the first resistor R1, then the first diode D1 is not conducting, and the anode voltage of the first diode D1 is 3.3V, which is a high level .
- the anode of the second diode D2 is connected to the voltage 3.3V of the first power supply terminal through the first resistor R1, then the second diode D2 is not conducting, and the anode voltage of the second diode D2 is 3.3V, which is high level. Since the receiving end RX2 of the second communication node 20, the receiving end RX of the first communication node 10, the anode of the second diode D2, and the anode of the first diode D1 are connected, the receiving end RX1 of the first communication node 10 The level is the same as the level of the transmitting end TX2 of the second communication node 20, and both are high levels.
- the on-board communication circuit can be used to implement on-board CAN communication between two communication nodes without adding an external CAN transceiver to the in-board communication node, thereby reducing hardware costs.
- the embodiments of the present application mainly describe the structure and working principle of the in-board communication circuit, and then describe optional means for optimizing the in-board communication circuit.
- FIG. 3 is obtained by further optimization on the basis of FIG. 2 b
- FIG. 3 is a schematic structural diagram of another on-board communication circuit disclosed in an embodiment of the present application.
- the on-board communication circuit described in this embodiment further includes: a first filter circuit and a second filter circuit; the first end 11 of the first resistor R1 is connected to the first communication node through the first filter circuit The receiving end RX1 of 10; the first end 21 of the second resistor R2 is connected to the receiving end RX2 of the second communication node 20 through the second filter circuit.
- the first filter circuit includes a third resistor R3 and a first capacitor C1
- the second filter circuit includes a fourth resistor R4 and a second capacitor C2
- the first end 71 of the first capacitor C1 is connected to the first end 51 of the third resistor R3 and The receiving end RX1 of the first communication node 10
- the second end 72 of the first capacitor C1 is connected to the first ground end
- the second end 52 of the third resistor R3 is connected to the first end 11 of the first resistor R1
- the first terminal 81 is connected to the second terminal 62 of the fourth resistor R4 and the receiving terminal RX2 of the second communication node 20
- the second terminal 82 of the second capacitor C2 is connected to the second ground terminal
- the first terminal 61 of the fourth resistor R4 is connected to The first end 21 of the second resistor R2.
- the receiving end of the communication node When communicating between communication nodes, the receiving end of the communication node may be interfered by various factors and it is difficult to receive pure signals.
- the first filter circuit and the second filter circuit have strong anti-interference, so that the on-board communication circuit can not only Realizing intra-board CAN communication between communication nodes can also reduce interference signals that may be received by the receiving end of the communication nodes, and realize more accurate intra-board CAN communication.
- first filter circuit and second filter circuit may also be added on the basis of FIG. 2 a , and the specific principle is similar to that of FIG. 3 , and details are not repeated here.
- FIG. 4 is a schematic structural diagram of an in-board communication device disclosed in an embodiment of the present application.
- the intra-board communication device described in this embodiment includes a first communication node 10 , a second communication node 20 , and the intra-board communication shown in any one of FIGS. 2 a , 2 b or 3 .
- the ground terminal 103 of the first communication node 10 and the ground terminal 203 of the second communication node 20 are connected to the same ground terminal;
- the power supply terminal 104 of the first communication node 10 is connected to the first auxiliary power supply, and the power supply terminal 204 of the second communication node 20 is connected to the second auxiliary power supply;
- Both the first communication node 10 and the second communication node 20 include a microcontroller unit MCU and a CAN controller.
- the micro-control unit MCU in the first communication node 10 and the micro-control unit MCU in the second communication node 20 may be the same micro-control unit, or may be different micro-control units.
- the micro-control unit MCU and the CAN controller are connected to each other and work together to form a communication node.
- the two communication nodes in the intra-board communication device realize intra-board CAN communication sharing the same ground terminal through the intra-board communication circuit.
- FIG. 5 is a schematic structural diagram of another in-board communication device disclosed in an embodiment of the present application.
- the intra-board communication device described in this embodiment includes a first communication node 10 , a second communication node 20 and the intra-board communication shown in any one of FIG. 2 a , FIG. 2 b or FIG. 3 .
- the ground terminal 103 of the first communication node 10 and the ground terminal 203 of the second communication node 20 are connected to the same ground terminal;
- the power supply terminal 104 of the first communication node 10 is connected to the first auxiliary power supply, and the power supply terminal 204 of the second communication node 20 is connected to the second auxiliary power supply;
- Both the first communication node 10 and the second communication node 20 include a micro-control unit MCU, and a CAN controller is integrated in the micro-control unit MCU.
- a CAN controller is integrated in the micro-control unit MCU, and the micro-control unit MCU may directly constitute a communication node.
- the two communication nodes in the intra-board communication device realize intra-board CAN communication sharing the same ground terminal through the intra-board communication circuit.
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Abstract
本申请实施例公开了一种板内通信电路及板内通信装置,其中,板内通信电路包括第一二极管、第二二极管和第一电阻;板内通信装置包括第一通信节点、第二通信节点和该板内通信电路。实施本申请实施例,可以在不使用CAN收发器的情况下,在板内实现通信节点之间的CAN通信,降低了硬件成本。
Description
本申请涉及电子电路技术领域,具体涉及一种板内通信电路及板内通信装置。
控制器局域网络(controller area network,CAN)总线是一种多主总线,即每个节点机均可成为主机,且节点机之间也可进行通信。CAN通信因性能卓越、设计独特、可靠性高等优点被广泛应用在汽车、医疗、船舶、航空等领域。
板内通信一般采用串行通信接口(serial communication interface,SCI)、串行外设接口(serial peripheral interface,SPI)、I2C(inter-integrated circuit,内置集成电路)等总线,但CAN总线有其独有的优势,板内通信采用CAN总线可充分利用其优势实现不同场景下的通信过程。在CAN通信中,每个通信节点通过CAN收发器在总线上发送和接收其他通信节点的信号。然而,在板内或片内进行CAN通信时,为板内或片内的每个通信节点外加一个CAN收发器,会导致硬件成本增加。
发明内容
本申请实施例提供一种板内通信电路及板内通信装置,在不使用CAN收发器的情况下,在板内实现CAN通信,降低了硬件成本。
本申请实施例第一方面,提供了一种板内通信电路,所述板内通信电路用于实现第一通信节点和第二通信节点之间的板内通信,所述板内通信电路包括第一二极管、第二二极管和第一电阻,其中:
所述第一通信节点的发送端连接所述第一二极管的负极,所述第一二极管的正极连接所述第一通信节点的接收端;所述第二通信节点的发送端连接所述第二二极管的负极,所述第二二极管的正极连接所述第二通信节点的接收端;所述第一电阻的第一端连接所述第一二极管的正极,所述第一电阻的第二端连接第一电源端;在所述第一通信节点的接收端连接所述第二通信节点的接收端的情况下,若所述第一通信节点的发送端和所述第二通信节点的发送端均为高 电平,所述板内通信电路实现所述第一通信节点的接收端和所述第二通信节点的接收端均为高电平。
可选的,若所述第一通信节点的发送端为低电平或所述第二通信节点的发送端为低电平,所述板内通信电路实现所述第一通信节点的接收端和所述第二通信节点的接收端均为低电平。
可选的,所述板内通信电路还包括第二电阻,所述第二电阻的第一端连接所述第二二极管的正极,所述第二电阻的第二端连接第二电源端,所述第一电源端与所述第二电源端的供电电平相同;
在所述第一通信节点的接收端连接所述第二通信节点的发送端,并且所述第一通信节点的发送端连接所述第二通信节点的接收端的情况下,若所述第一通信节点的发送端为低电平或所述第二通信节点的发送端为低电平,所述板内通信电路实现所述第一通信节点的接收端和所述第二通信节点的接收端均为低电平。
可选的,所述板内通信电路还包括第一滤波电路;所述第一二极管的正极通过所述第一滤波电路连接所述第一通信节点的接收端。
可选的,所述第一滤波电路包括第三电阻和第一电容;所述第一电容的第一端连接所述第三电阻的第一端、所述第一通信节点的接收端,所述第一电容的第二端连接第一地端,所述第三电阻的第二端连接所述第一二极管的正极。
可选的,所述板内通信电路还包括第二滤波电路;所述第二二极管的正极通过所述第二滤波电路连接所述第二通信节点的接收端。
可选的,所述第二滤波电路包括第四电阻和第二电容;所述第二电容的第一端连接所述第四电阻的第二端、所述第二通信节点的接收端,所述第二电容的第二端连接第二地端,所述第四电阻的第一端连接所述第二二极管的正极。
本申请实施例第二方面,提供了一种板内通信装置,所述板内通信装置包括第一通信节点、第二通信节点和本申请实施例第一方面中的任一种板内通信电路。
其中,所述第一通信节点和所述第二通信节点的接地端连接同一个地端。
其中,所述第一通信节点和所述第二通信节点均包括微控制单元和CAN 控制器。
其中,可选地,所述第一通信节点和所述第二通信节点均包括微控制单元,所述微控制单元内集成有CAN控制器。
其中,所述第一通信节点的电源端连接第一辅助电源,所述第二通信节点的电源端连接第二辅助电源。
本申请实施例提供了一种板内通信电路,包括第一二极管、第二二极管和第一电阻,该板内通信电路结构简单、采用的电子元器件少。实施本申请实施例,在第一通信节点的发送端和第二通信节点的发送端均为高电平的情况,板内通信电路可以实现所述第一通信节点的接收端和所述第二通信节点的接收端均为高电平,从而在无需CAN收发器的情况下实现板内CAN通信,降低了硬件成本。
为了更清楚地说明本申请实施例或现有技术中的技术方案,下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍,显而易见地,下面描述中的附图仅仅是本申请的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动的前提下,还可以根据这些附图获得其他的附图。
图1a为传统方法中使用CAN收发器的CAN通信示意图;
图1b是本申请实施例公开的板内通信电路实现的CAN通信的信号示意图;
图1c是本申请实施例公开的板内通信电路实现的CAN通信的电平示意图;
图2a是本申请实施例公开的一种板内通信电路的结构示意图;
图2b是本申请实施例公开的另一种板内通信电路的结构示意图;
图3是本申请实施例公开的另一种板内通信电路的结构示意图;
图4是本申请实施例公开的一种板内通信装置的结构示意图;
图5是本申请实施例公开的另一种板内通信装置的结构示意图。
下面将结合本申请实施方式中的附图,对本申请实施方式中的技术方案进行清楚、完整地描述。显然,所描述的实施方式是本申请的一部分实施方式,而不是全部实施方式。基于本申请中的实施方式,本领域普通技术人员在没有做出创造性劳动的前提下所获得的所有其他实施方式,都应属于本申请保护的范围。
在CAN通信中,每个通信节点是通过CAN收发器在总线上发送和接收其他通信节点的信号,因此,每个通信节点必须外加一个CAN收发器。另外,要实现CAN通信还需要CAN控制器。
图1a为传统方法中使用CAN收发器的CAN通信示意图。如图1a所示,以通信节点为微控制单元MCU(micro controller unit,MCU)为例,CAN控制器集成在微控制单元MCU内部。CAN控制器可以接收微控制单元MCU中的微处理器发出的数据,并将数据传给CAN收发器;CAN收发器用于将数据传到总线或从总线接收数据传给CAN控制器。但是,在板内实现CAN通信时,为每个通信节点外加一个CAN收发器会增加板内通信的成本。
请参阅图1b,图1b是本申请实施例公开的一种采用CAN收发器实现CAN通信的CAN信号示意图。图1b是基于图1a使用CAN收发器的CAN通信中的CAN信号示意图。CAN信号是一种以显性电平和隐性电平交替出现的比特流信号,CAN信号可以包括传输控制命令,也可以包括数据段或数据块。CAN信号中,以“0”代表显性,显性对应为低电平,以“1”代表隐性,隐性对应为高电平。如图1b所示,CAN信号以控制命令为例,CAN信号在第一个时间段内为显性电平“0”、第二个时间段内为隐性电平“1”、第三个时间段内为显性电平“0”、第四个时间段内为显性电平“0”、第五个时间段内为隐性电平“1”,可以将这五个时间段的时长之和作为一个周期,在下一周期又会重复出现这五个时间段对应的电平,可以用于周期性的传输同一控制命令。
请参阅图1c,图1c是本申请实施例公开的一种采用CAN收发器实现CAN 通信的CAN信号的电平示意图。图1c是基于图1a的使用CAN收发器的CAN通信中的CAN信号的电平示意图。如图1c所示,CAN信号中的显性电平和隐性电平不是对应两个具体数值的电压,而是对应为两个电压范围,例如,CAN信号中的显性电平为“0V~1.5V”时,相应的隐性电平为“1.5V~5V”;CAN信号中的显性电平为“0V~2.5V”时,相应的隐性电平为“2.5V~5V”;CAN信号中的显性电平为“0V~3.5V”时,相应的隐性电平为“3.5V~5V”。
本申请实施例提供一种板内通信电路及板内通信装置,可以在不使用CAN收发器的情况下,在板内实现CAN通信。以下进行详细说明。
请参阅图2a,图2a是本申请实施例公开的一种板内通信电路的结构示意图。如图2a所示,本实施例中所描述的板内通信电路30用于实现第一通信节点10和第二通信节点20之间的板内通信,板内通信电路包括第一二极管D1、第二二极管D2和第一电阻R1,其中:
第一通信节点10的发送端TX1连接第一二极管D1的负极,第一二极管D1的正极连接第一通信节点10的接收端RX1;第二通信节点20的发送端TX2连接第二二极管D2的负极,第二二极管D2的正极连接第二通信节点20的接收端RX2;第一电阻R1的第一端连接第一二极管D1的正极,第一电阻R1的第二端连接第一电源端;
在第一通信节点10的接收端RX1连接第二通信节点20的接收端RX2的情况下,若第一通信节点10的发送端TX1和第二通信节点20的发送端TX2均为高电平,板内通信电路30实现第一通信节点10的接收端RX1和第二通信节点20的接收端RX2均为高电平;
若所述第一通信节点10的发送端TX1为低电平或所述第二通信节点20的发送端TX2为低电平,所述板内通信电路30实现所述第一通信节点10的接收端RX1和所述第二通信节点20的接收端RX2均为低电平。
本申请实施例的板内通信电路30适用于第一通信节点和第二通信节点均可以输出高电平或低电平的情况下。
本申请实施例中,在第一通信节点10的发送端TX1为高电平、第二通信节点20的发送端TX2为高电平的情况下,板内通信电路30中的第一二极管 D1不导通,第二二极管D2不导通,此时第一通信节点10的接收端RX1和第二通信节点20的接收端RX2受到第一电源端的高电平控制,则均为高电平;
在第一通信节点10的发送端TX1为低电平、第二通信节点20的发送端TX2为低电平的情况下,板内通信电路30中的第一二极管D1和第二二极管D2均导通,由于第一二极管D1和第二二极管D2正向导通时的压降只有零点几伏,此时第一通信节点10的接收端RX1和第二通信节点20的接收端RX2均为低电平;
在第一通信节点10的发送端TX1为低电平、第二通信节点20的发送端TX2为高电平的情况下,板内通信电路30中的第一二极管D1导通,第二二极管D2不导通,此时第一通信节点10的接收端RX1为低电平,由于第一通信节点10的接收端RX1和第二通信节点20的接收端RX2连接,则第二通信节点20的接收端RX2也为低电平;
在第一通信节点10的发送端TX1为高电平、第二通信节点20的发送端TX2为低电平的情况下,板内通信电路30中的第一二极管D1不导通,第二二极管D2导通,此时第二通信节点20的接收端RX2为低电平,由于第一通信节点10的接收端RX1和第二通信节点20的接收端RX2连接,则第一通信节点10的接收端RX1也为低电平。
本申请实施例中,第一通信节点10和第二通信节点20可以通过板内通信电路30实现控制器局域网络CAN总线通信。第一通信节点10和第二通信节点20可以通过板内通信电路30进行数据传输和控制命令传输。
其中,第一二极管D1、第二二极管D2可以采用具有二极管功能(即,单向导通,反向截止的功能)的替代电路来实现,本申请实施例不做限定。
本申请实施例提供的板内通信电路,包括第一二极管、第二二极管、和第一电阻,该板内通信电路结构简单、采用的电子元器件少。实施本申请实施例,在第一通信节点的发送端和第二通信节点的发送端均为高电平的情况下,板内通信电路可以实现所述第一通信节点的接收端和所述第二通信节点的接收端均为高电平,从而在无需CAN收发器的情况下实现板内CAN通信,降低了硬件成本。
请参阅图2b,图2b是本申请实施例公开的另一种板内通信电路30的结构示意图。如图2b所示,本实施例中所描述的板内通信电路30用于实现第一通信节点10和第二通信节点20之间的板内通信,板内通信电路包括第一二极管D1、第二二极管D2、第一电阻R1和第二电阻R2,其中:
第一通信节点10的发送端TX1连接第一二极管D1的负极,第一二极管D1的正极连接第一通信节点10的接收端RX1;第二通信节点20的发送端TX2连接第二二极管D2的负极,第二二极管D2的正极连接第二通信节点20的接收端RX2;第一电阻R1的第一端连接第一二极管D1的正极,第一电阻R1的第二端连接第一电源端;
所述第二电阻R2的第一端连接所述二二极管D2的正极,所述第二电阻R2的第二端连接第二电源端,所述第一电源端与所述第二电源端的供电电平相同;
在所述第一通信节点10的接收端RX1连接所述第二通信节点20的发送端TX2,并且所述第一通信节点10的发送端TX1连接所述第二通信节点20的接收端RX2的情况下,若所述第一通信节点10的发送端TX1为低电平或所述第二通信节点20的发送端TX2为低电平,所述板内通信电路30实现所述第一通信节点10的接收端RX1和所述第二通信节点20的接收端RX2均为低电平。
本申请实施例的板内通信电路30适用于第一通信节点10和第二通信节点20只能输出低电平的情况下,比如,第一通信节点10和第二通信节点20均为集电极开路(Open Collector,OC)门的情况。
板内通信电路30用于在第一通信节点10的发送端TX1或第二通信节点20的发送端TX2为低电平的情况下,实现第一通信节点10的接收端RX1和第二通信节点20的接收端RX2均为低电平;
在第一通信节点10的发送端TX1为低电平、第二通信节点20的发送端TX2为低电平的情况下,板内通信电路30中的第一二极管D1和第二二极管D2均导通,此时第一通信节点10的接收端RX1和第二通信节点20的接收端RX2均为低电平。
本申请实施例中,第一通信节点10和第二通信节点20可以通过板内通信电路30实现控制器局域网络CAN总线通信。第一通信节点10和第二通信节点20可以通过板内通信电路30进行数据传输和控制命令传输。
其中,第一二极管D1、第二二极管D2可以采用具有二极管功能(即,单向导通,反向截止的功能)的替代电路来实现,本申请实施例不做限定。
其中,CAN总线可以用于传输数据,也可以用于传输控制命令。传输数据时,可以以数据块为单位,对数据块进行编码,得到以比特(二进制数的一位包含的信息=1比特)为最小单位的数据块。
CAN,是国际上应用最广泛的现场总线之一。20世纪80年代初,德国Bosch公司为了解决现代汽车中众多的控制与测试仪表之间的数据交换问题,开发出CAN总线。CAN总线能有效支持分布式控制或实时控制的串行通信网络,具有抗干扰性强和使用可靠等优点,最初主要应用汽车工业,现在广泛应用于汽车工业、航空工业和工业控制等自动化领域,如分布式环境监测系统、温室环境监控系统、变电站变监测系统等。
CAN总线是一种串行数据通信协议,其通信接口(比如,第一通信节点10和第二通信节点20)中集成了CAN协议的物理层和数据链路层功能,可完成对数据的成帧处理,包括位填充、数据块编码、循环冗余校验、优先级判别等项工作。用户可在其基础上开发适应系统实际需要的应用层通信协议。CAN协议的一个最大特点是废除了传统的站地址编码,而代之以对通信数据块编码,采用这种方法可使网络内节点个数在理论上不受限制,还可使不同的节点同时收到相同的数据。
CAN总线具有如下优点:
(1)CAN总线是一种多主总线,即每个节点机均可成为主机,且节点机之间也可进行通信;
(2)CAN总线的通信介质可以是双绞线、同轴电缆或光导纤维,通信速率可达1Mbps;
(3)CAN总线中传输的数据段长度最多为8个字节,可满足通常工业领域中控制命令,工作状态及测试数据的一般要求。同时,8个字节不会占用总 线时间过长,从而保证了通信的实时性;
(4)CAN协议采用循环冗余校验码(cyclic redundancy check,CRC)校验并可提供相应的错误处理功能,保证了数据通信的可靠性;
(5)CAN可以以多主方式工作,网络上任意节点均可以在任意时刻主动地向总线上其它节点发送信息,实现点对点、一点对多点及全局广播几种方式发送接收数据;
(6)CAN采用非破坏性总线仲裁技术,当两个节点同时向总线上发送信息时,优先级低的节点主动停止数据发送,而优先级高的节点可不受影响地继续传输数据,节省了总线冲突仲裁时间。
CAN总线的典型的应用场景:主节点接收其他节点发送的现场数据,如现场温度、电流、压力等参数,主节点经过处理后生成各种控制命令,并通过CAN总线将控制命令发送至各个其他节点。
本申请实施例中,第一电阻R1和第二电阻R2为上拉电阻,第一电阻R1和第二电阻R2的阻值可以相同,也可以不同。第一电阻R1和第二电阻R2可以提高通信节点接收端的信号的噪声容限,增强抗干扰能力。第一二极管D1、第二二极管D2可以为普通开关二极管、低功耗开关二极管等,第一二极管D1与第二二极管D2的参数可以相同,也可以不同。
本申请实施例中,板内通信电路可以用于无需大电缆线来承载大电流的板中,如印制电路板(printed circuit board,PCB)等,通信节点可以为微控制单元MCU,也可以为微控制单元MCU与其他电子元件相互连接的单元,还可以为包含微控制单元MCU的集成电子器件。
请参阅表1,表1是图2a和图2b的板内通信电路的通信节点之间的电平变化。表1中,高电平为“1”,低电平为“0”。从表1可以看出,只要第一通信节点和第二通信节点的其中任意一个发送端(TX1或TX2)为低电平,第一通信节点和第二通信节点的接收端(RX1和RX2均为低电平,当第一通信节点和第二通信节点的发送端(TX1和TX2)均为高电平时,第一通信节点和第二通信节点的接收端(RX1和RX2均为高电平。图2a和图2b的板内通信电路不采用图1a的CAN收发器,不采用CAN信号,也能实现CAN通 信的功能。
高电平和低电平分别对应的是数字信号的“1”和“0”。高电平对应的模拟信号的电压范围和低电平对应的模拟信号的电压范围没有交集。举例来说,高电平对应的模拟信号的电压范围为大于2.5V,低电平对应的模拟信号的电压范围为0~1.2V。
表1
在第一通信节点10的发送端TX1为低电平、第二通信节点20的发送端TX2为低电平的情况下,板内通信电路30中的第一二极管D1和第二二极管D2均导通,实现第一通信节点10的接收端RX1和第二通信节点20的接收端RX2均为低电平。如图2a所示,假定第一电源端的电平预设为3.3V,高电平对应的模拟信号的电压范围为2.5~10V,低电平对应的模拟信号的电压范围为0~1.2V。第一通信节点10的发送端TX1为低电平(比如,0V)、第二通信节点20的发送端TX2为低电平(比如,0V),由于第一二极管D1的负极为0V,第一二极管D1的正极通过第一电阻R1连接第一电源端的电压3.3V,则第一二极管D1导通。类似的,由于第二二极管D2的负极为0V,第二二极管D2的正极通过第一电阻R1连接第一电源端的电压3.3V,则第二二极管D1导通。第一二极管D1和第二二极管D2均导通之后,由于二极管的导通压降一般为0.2~0.7V,第一二极管D1的正极和第二二极管D2的正极均为0.2~0.7V,为低电平,由于第二通信节点20的接收端RX2、第一通信节点10的接收端RX、第二二极管D2的正极、第一二极管D1的正极相连,则第一通信节点10的接收端RX1和第二通信节点20的接收端RX2均为低电平。
在第一通信节点10的发送端TX1为低电平、第二通信节点20的发送端 TX2为高电平的情况下,板内通信电路30中的第一二极管D1导通,第二二极管D2不导通,实现第一通信节点10的接收端RX1和第二通信节点20的接收端RX2均为低电平。如图2a所示,假定第一电源端的电平预设为3.3V,高电平对应的模拟信号的电压范围为2.5~10V,低电平对应的模拟信号的电压范围为0~1.2V。第一通信节点10的发送端TX1为低电平(比如,0V),即第一二极管D1的负极32的电压为“0”,第二通信节点20的发送端TX2为高电平(比如,5V),即第二二极管D2的负极42的电压为“5V”。由于第一二极管D1的负极为0V,第一二极管D1的正极通过第一电阻R1连接第一电源端的电压3.3V,则第一二极管D1导通,由于二极管的导通压降一般为0.2~0.7V,为低电平,第一二极管D1的正极电压为0.2~0.7V。由于第二二极管D2的负极为5V,第二二极管D2的正极通过第一电阻R1连接第一电源端的电压3.3V,则第二二极管D2不导通,第二二极管D2的正极电压等于第一二极管D1的正极电压(即,0.2~0.7V),同样为低电平由于第二通信节点20的接收端RX2、第一通信节点10的接收端RX、第二二极管D2的正极、第一二极管D1的正极相连,则第二通信节点20的接收端RX2电平与第一通信节点10的接收端RX1电平相同,均为低电平。
在第一通信节点10的发送端TX1为高电平、第二通信节点20的发送端TX2为低电平的情况下,板内通信电路30中的第一二极管D1不导通,第二二极管D2导通,实现第一通信节点10的接收端RX1和第二通信节点20的接收端RX2均为低电平。如图2a所示,假定第一电源端的电平预设为3.3V,高电平对应的模拟信号的电压范围为2.5~10V,低电平对应的模拟信号的电压范围为0~1.2V。第一通信节点10的发送端TX1为高电平(比如,5V),即第一二极管D1的负极32的电压为“5V”,第二通信节点20的发送端TX2为低电平(比如,0V),,即第二二极管D2的负极42的电压为“0V”。由于第二二极管D2的负极为0V,第二二极管D2的正极通过第一电阻R1连接第一电源端的电压3.3V,则第二二极管D2导通,由于二极管的导通压降一般为0.2~0.7V,第二二极管D2的正极电压为0.2~0.7V,为低电平。由于第一二极管D1的负极为5V,第一二极管D1的正极通过第一电阻R1连接第一电源端 的电压3.3V,则第一二极管D1不导通,第二二极管D2的正极电压等于第一二极管D1的正极电压(即,0.2~0.7V),同样为低电平。由于第二通信节点20的接收端RX2、第一通信节点10的接收端RX、第二二极管D2的正极、第一二极管D1的正极相连,则第一通信节点10的接收端RX1电平与第二通信节点20的接收端RX2电平均为低电平。
在第一通信节点10的发送端TX1和第二通信节点20的发送端TX2均为高电平的情况下,板内通信电路30中的第一二极管D1和第二二极管D2均不导通,实现第一通信节点10的接收端RX1和第二通信节点20的接收端RX2均为高电平。如图2a所示,假定第一电源端的电平预设为3.3V,高电平对应的模拟信号的电压范围为2.5~10V,低电平对应的模拟信号的电压范围为0~1.2V。第一通信节点10的发送端TX1和第二通信节点20的发送端TX2均为高电平(比如,5V),即第一二极管D1的负极32的电压为“5V”,同样地,第二二极管D2的负极42的电压也为“5V”。第一二极管D1的正极通过第一电阻R1连接第一电源端的电压3.3V,则第一二极管D1不导通,第一二极管D1的正极电压为3.3V,为高电平。类似的,第二二极管D2的正极通过第一电阻R1连接第一电源端的电压3.3V,则第二二极管D2不导通,第二二极管D2的正极电压为3.3V,为高电平。由于第二通信节点20的接收端RX2、第一通信节点10的接收端RX、第二二极管D2的正极、第一二极管D1的正极相连,则第一通信节点10的接收端RX1电平与第二通信节点20的发送端TX2电平相同,均为高电平。
本申请实施例中,板内通信电路可以用于在板内的通信节点没有外加CAN收发器的情况下,实现两个通信节点之间的板内CAN通信,降低了硬件成本。本申请实施例主要说明了板内通信电路的结构及工作原理,接下来阐述对板内通信电路进行优化的可选手段。
可选的,请参阅图3,图3是在图2b的基础上进一步优化得到的,图3是本申请实施例公开的另一种板内通信电路的结构示意图。如图3所示,本实施例中所描述的板内通信电路,还包括:第一滤波电路和第二滤波电路;第一电阻R1的第一端11通过第一滤波电路连接第一通信节点10的接收端RX1; 第二电阻R2的第一端21通过第二滤波电路连接第二通信节点20的接收端RX2。其中:
第一滤波电路包括第三电阻R3和第一电容C1,第二滤波电路包括第四电阻R4和第二电容C2;第一电容C1的第一端71连接第三电阻R3的第一端51以及第一通信节点10的接收端RX1,第一电容C1的第二端72连接第一地端,第三电阻R3的第二端52连接第一电阻R1的第一端11;第二电容C2的第一端81连接第四电阻R4的第二端62以及第二通信节点20的接收端RX2,第二电容C2的第二端82连接第二地端,第四电阻R4的第一端61连接第二电阻R2的第一端21。
通信节点之间进行通信时,通信节点的接收端可能受到各种因素的干扰而很难接收到纯净的信号,第一滤波电路和第二滤波电路抗干扰性强,使板内通信电路不仅可以实现通信节点之间的板内CAN通信,还可以减少通信节点的接收端可能收到的干扰信号,实现更精确的板内CAN通信。
可选的,还可以在图2a的基础上增加上述第一滤波电路和第二滤波电路,具体原理与图3类似,此处不再赘述。
请参阅图4,图4是本申请实施例公开的一种板内通信装置的结构示意图。如图4所示,本实施例中所描述的板内通信装置,包括第一通信节点10、第二通信节点20和如图2a、图2b或图3中任意一项所示的板内通信电路30。其中:
第一通信节点10的接地端103和第二通信节点20的接地端203连接同一个地端;
第一通信节点10的电源端104连接第一辅助电源,第二通信节点20的电源端204连接第二辅助电源;
第一通信节点10和第二通信节点20均包括微控制单元MCU和CAN控制器。
本申请实施例中,第一通信节点10中的微控制单元MCU与第二通信节点20中的微控制单元MCU可以是相同的微控制单元,也可以是不同的微控制单元。
本申请实施例中,微控制单元MCU和CAN控制器互相连接、协同工作,共同构成一个通信节点。板内通信装置中的两个通信节点通过板内通信电路实现共用同一个地端的板内CAN通信。
请参阅图5,图5是本申请实施例公开的另一种板内通信装置的结构示意图。如图5所示,本实施例中所描述的板内通信装置,包括第一通信节点10、第二通信节点20和如图2a、图2b或图3中任意一项所示的板内通信电路30。其中:
第一通信节点10的接地端103和第二通信节点20的接地端203连接同一个地端;
第一通信节点10的电源端104连接第一辅助电源,第二通信节点20的电源端204连接第二辅助电源;
第一通信节点10和第二通信节点20均包括微控制单元MCU,微控制单元MCU内集成有CAN控制器。
本申请实施例中,微控制单元MCU中集成有CAN控制器,微控制单元MCU可以直接构成一个通信节点。板内通信装置中的两个通信节点通过板内通信电路实现共用同一个地端的板内CAN通信。
以上对本申请实施例所提供的一种板内通信电路及板内通信装置进行了详细介绍,本文中应用了具体个例对本申请的原理及实施方式进行了阐述,以上实施例的说明只是用于帮助理解本申请的方法及其核心思想;同时,对于本领域的一般技术人员,依据本申请的思想,在具体实施方式及应用范围上均会有改变之处,综上所述,本说明书内容不应理解为对本申请的限制。
Claims (10)
- 一种板内通信电路,所述板内通信电路用于实现第一通信节点和第二通信节点之间的板内通信,其特征在于,所述板内通信电路包括第一二极管、第二二极管和第一电阻;所述第一通信节点的发送端连接所述第一二极管的负极,所述第一二极管的正极连接所述第一通信节点的接收端;所述第二通信节点的发送端连接所述第二二极管的负极,所述第二二极管的正极连接所述第二通信节点的接收端;所述第一电阻的第一端连接所述第一二极管的正极,所述第一电阻的第二端连接第一电源端;在所述第一通信节点的接收端连接所述第二通信节点的接收端的情况下,若所述第一通信节点的发送端和所述第二通信节点的发送端均为高电平,所述板内通信电路实现所述第一通信节点的接收端和所述第二通信节点的接收端均为高电平。
- 根据权利要求1所述的板内通信电路,其特征在于,若所述第一通信节点的发送端为低电平或所述第二通信节点的发送端为低电平,所述板内通信电路实现所述第一通信节点的接收端和所述第二通信节点的接收端均为低电平。
- 根据权利要求1所述的板内通信电路,其特征在于,所述板内通信电路还包括第二电阻,所述第二电阻的第一端连接所述第二二极管的正极,所述第二电阻的第二端连接第二电源端,所述第一电源端与所述第二电源端的供电电平相同;在所述第一通信节点的接收端连接所述第二通信节点的发送端,并且所述第一通信节点的发送端连接所述第二通信节点的接收端的情况下,若所述第一通信节点的发送端为低电平或所述第二通信节点的发送端为低电平,所述板内通信电路实现所述第一通信节点的接收端和所述第二通信节点的接收端均为低电平。
- 根据权利要求1~3任一项所述的板内通信电路,其特征在于,所述板内通信电路还包括第一滤波电路;所述第一二极管的正极通过所述第一滤波电路连接所述第一通信节点的接收端。
- 根据权利要求4所述的板内通信电路,其特征在于,所述第一滤波电路包括第三电阻和第一电容;所述第一电容的第一端连接所述第三电阻的第一端、所述第一通信节点的接收端,所述第一电容的第二端连接第一地端,所述第三电阻的第二端连接所述第一二极管的正极。
- 根据权利要求4或5所述的板内通信电路,其特征在于,所述板内通信电路还包括第二滤波电路;所述第二二极管的正极通过所述第二滤波电路连接所述第二通信节点的接收端。
- 根据权利要求6所述的板内通信电路,其特征在于,所述第二滤波电路包括第四电阻和第二电容;所述第二电容的第一端连接所述第四电阻的第二端、所述第二通信节点的接收端,所述第二电容的第二端连接第二地端,所述第四电阻的第一端连接所述第二二极管的正极。
- 一种板内通信装置,其特征在于,所述板内通信装置包括第一通信节点、第二通信节点和权利要求1~7任一项所述的板内通信电路。
- 根据权利要求8所述的板内通信装置,其特征在于,所述第一通信节点和所述第二通信节点的接地端连接同一个地端。
- 根据权利要求8所述的板内通信装置,其特征在于,所述第一通信节点和所述第二通信节点均包括微控制单元和CAN控制器。
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