Controllers and transceivers

Abstract

The present disclosure relates to a controller and a transceiver and associated software and methods. A controller having a first operation mode and a second operation mode for communicating with a transceiver in a network node, the controller comprising: a first data terminal for communicating with the transceiver; and a second data terminal for communicating with the transceiver, wherein the controller is configured to: in the second mode, determine received data based on a first data signal at the first data terminal and a second data signal at the second data terminal; determine that a mode needs to be changed from the second mode to the first mode; and in response to determining that a mode needs to be changed from the second mode to the first mode, provide a controller mode signal indicating that the transceiver operates in the first mode instead of the second mode, wherein the controller mode signal is provided by driving a first current on the first data terminal and a second current on the second data terminal at the same time.

Description

Technical Field

[0001] The present disclosure relates to a transceiver and a controller for a network node, a network comprising said node, and associated operating methods and corresponding computer programs. In particular, although not exclusively, the present disclosure relates to a CAN transceiver, a CAN controller, a CAN device, a CAN network, and associated operating methods. Background Art

[0002] For example, Controller Area Network (CAN), CAN with Flexible Data Rate (CAN FD), Local Interconnect Network (LIN), FlexRay, Ethernet-based network buses, and other types of In-Vehicle Network (IVN) buses can be used for communication within the vehicle. For example, the Controller Area Network (CAN) bus is a message-based communication bus protocol commonly used in automobiles. A CAN bus network may include multiple bus devices, so-called nodes or electronic control units (ECUs), such as engine control modules (ECMs), powertrain control modules (PCMs), airbags, anti-lock brakes, cruise control, electric power steering, audio systems, windows, doors, mirror adjustments, battery and recharging systems for hybrid / electric vehicles, and the like. The CAN bus protocol is used to enable communication between the various bus devices. The data link layer of the CAN protocol is standardized as International Organization for Standardization (ISO) 11898-1:2003. CAN Flexible Data Rate or "CAN FD", which is an extension of the standardized CAN data link layer protocol and is integrated into the ISO 11898-2:2016 standard, can provide higher data rates. However, the standardized CAN data link layer protocol is still in the process of further extension to provide higher data rates. Another extension called CAN XL with a new level scheme to achieve higher data rates is in the definition stage under discussion according to CiA610 (CAN in Automation, CiA), discussed in the draft specification CiA610-1, and is moving towards standardization in the form of an additional update of the existing ISO11898 standard or a new standard. Summary of the invention

[0003] According to a first aspect, there is provided a controller having a first mode of operation and a second mode of operation for communicating with a transceiver in a network node, the controller comprising:

[0004] A first data port for communicating with the transceiver; and

[0005] a second data terminal for communicating with the transceiver,

[0006] The controller may include a processor configured to:

[0007] in the second mode, determining received data based on a first data signal at the first data end and a second data signal at the second data end;

[0008] determining that a mode change from the second mode to the first mode is required; and

[0009] In response to determining that a mode change from the second mode to the first mode is required, providing a controller mode signal indicating that the transceiver operates in the first mode rather than the second mode, wherein the controller mode signal is provided by simultaneously driving a first current on the first data terminal and a second current on the second data terminal.

[0010] The received data may be encoded as a differential signal received at the first data terminal and the second data terminal of the controller.

[0011] The controller may be configured to determine that a mode change from the second mode to the first mode is required based on the received data.

[0012] According to an example, the controller is configured to provide the controller mode signal by driving a first current on the first data terminal and a second current on the second data terminal. The first current and the second current may have the same polarity.

[0013] The first current and the second current may be in the same direction. That is, both currents may flow into the controller, or both currents may flow out of the controller. The first current and the second current may be inflow currents. The first current and the second current may be outflow currents.

[0014] According to an example, the controller is further configured to provide the controller mode signal by driving both the first data terminal and the second data terminal to the same logic state.

[0015] The controller may be configured to provide the controller mode signal by driving both the first data terminal and the second data terminal to the same or substantially the same voltage level.

[0016] According to an example, the controller is configured to provide the controller mode signal by driving both the first data terminal and the second data terminal to a low logic state.

[0017] The controller may be configured to provide the controller mode signal by driving both the first data terminal and the second data terminal to a high logic state.

[0018] The controller may include a first strong driver for driving the first current at the first data terminal and a second strong driver for driving the second current at the second data terminal.

[0019] According to an example, the controller includes a first strong inflow driver for driving the first current at the first data terminal and a second strong inflow driver for driving the second current at the second data terminal.

[0020] The controller may include a first strong outgoing driver for driving the first current at the first data terminal. The controller may include a second strong outgoing driver for driving the second current at the second data terminal.

[0021] The magnitude of a strong current may be greater than the magnitude of a weak current. In this context, the terms "weak" and "strong" may be used relatively.

[0022] The duration of the control mode signal may be at least one of 30, 50, 90, 100, 120, 200 ns. The duration of the control mode signal may be between 90 ns and 110 ns.

[0023] The controller may additionally be configured to:

[0024] in a third operating mode, providing transmission data using the signal at the first data terminal and the signal at the second data terminal;

[0025] In response to determining that a mode change from the third mode to the first mode is required, providing a controller mode signal indicating that the transceiver operates in the first mode rather than the third mode, wherein the controller mode signal is provided by simultaneously driving a first current on the first data terminal and a second current on the second data terminal.

[0026] The transmission data may be encoded as a differential signal provided at the first data terminal and the second data terminal of the controller.

[0027] According to an example, the controller is a CAN controller.The CAN controller may be configured to operate in a first mode according to ISO 11898-1:2003.

[0028] Weak current can be in the range of 2mA to 8mA. Strong current can be greater than 8mA.

[0029] According to another aspect, there is provided a transceiver for communicating with a controller in a network node and a network bus external to the node having a first mode of operation and a second mode of operation, the transceiver comprising:

[0030] at least one bus terminal for communicating with the network bus;

[0031] a first data terminal for communicating with the controller;

[0032] A second data terminal for communicating with the controller,

[0033] a receiver configured to generate receive data for the controller based on a bus signal received at the at least one bus terminal in the second mode, wherein the receive data is provided by the transceiver driving a first current on the first data terminal and driving an opposite second current to the second data terminal;

[0034] The transceiver is configured to:

[0035] in the second operation mode, monitoring the first data terminal and the second data terminal for a controller mode signal indicating a need to change a mode from the second mode to the first mode, wherein the controller mode signal is provided by a logic level at the first data terminal being the same as a logic level at the second data terminal; and

[0036] A mode is changed from the second mode to the first mode based on detecting the controller mode signal.

[0037] The magnitude of the first current is different from the magnitude of the second current. One of the first current and the second current is a weak current, while the other is a strong current. One of the first current and the second current drives a voltage level toward a logical low, while the other drives the voltage level toward a logical high.

[0038] According to an example, the transceiver includes a first output driver coupled to the first data terminal of the transceiver and a second output driver coupled to the second data terminal of the transceiver. Each output driver may include a weak outflow driver and a strong inflow driver for providing a corresponding first current and a second current. Alternatively, each output driver may include a strong outflow driver and a weak inflow driver. In general, each output driver may include a strong driver and a weak driver. The current provided by the weak driver may be a current opposite to the current provided by the strong driver.

[0039] The receiver of the transceiver may be configured to control the first output driver to provide the first current and control the second output driver to provide the second current according to the bus signal.

[0040] According to an example, the transceiver includes logic configured to perform an exclusive-OR (XOR) operation or an exclusive-NOR (XNOR) operation on signals from the first data terminal and the second data terminal.

[0041] The received data may be encoded as a differential signal received at the first data terminal and the second data terminal of the controller.

[0042] The transceiver may additionally include:

[0043] a transmitter configured to receive transmission data for the controller in a third mode and to generate a bus signal for the at least one bus terminal based on the transmission signal, wherein the transmission data is provided by the controller at the first first data terminal and the second data terminal as a differential signal;

[0044] The transceiver is configured to:

[0045] In the third operation mode, monitoring the first data terminal and the second data terminal for a controller mode signal indicating a need to change a mode from the third mode to the first mode, wherein the controller mode signal is provided by a logic level at the first data terminal being the same as a logic level at the second data terminal; and

[0046] A mode is changed from the third mode to the first mode based on detecting the controller mode signal.

[0047] According to an example, the transceiver includes a transmitter having an input coupled to the first data terminal and at least one output connected to a CAN bus terminal. The transmitter may be configured to convert data received at the first data terminal into a differential signal for a CAN bus in the first mode. The transmitter may include a first data terminal repeater unit for the first mode. The repeater unit may include a forward path buffer between the first data terminal and the transmitter that may be provided by a Schmitt trigger. The repeater unit may include a feedback path between the first data terminal and the transmitter.

[0048] The transmitter may include a second data end repeater unit for the first mode. The second data end repeater unit may include a forward path buffer between the second data end and the receiver. The second data end repeater unit may include a feedback path between the second data end and the receiver. The receiver may include an output driver coupled to the second data end. The output driver may have a maximum active pulse time.

[0049] In one example, the output driver is configured to be in a high impedance state after the maximum active pulse time has elapsed.

[0050] In one example, the transceiver has a third operating mode. The transmitter may be configured to convert data received at the first data end into a differential signal for the CAN bus in the third mode using a conversion scheme different from the conversion in the first mode. The transceiver may include a first data end repeater unit for the third mode. The first data end repeater unit may include a forward path buffer between the first data end and the transmitter. The first data end repeater unit may include a feedback path between the first data end and the transmitter. The transceiver may include a second data end repeater unit for the third mode. The second data end repeater unit may include a forward path buffer between the second data end and the receiver. The second data end repeater unit may include a feedback path between the second data end and the receiver.

[0051] In one example, the transceiver is a CAN transceiver.

[0052] The controller and the transceiver may be arranged in different device packages. The first data terminal and the second data terminal may be provided by pins of corresponding device packages.

[0053] According to another aspect, there is provided a node comprising a controller as described herein and a transceiver as described herein.

[0054] According to another aspect, a CAN network comprising at least one node as described herein may be provided.

[0055] According to another aspect, there is provided a method of operating a controller having a first mode of operation and a second mode of operation in communication with a transceiver in a network node, the method comprising:

[0056] in the second mode, determining received data based on a signal at a first data terminal and a signal at a second data terminal of the controller;

[0057] determining that a mode change from the second mode to the first mode is required; and

[0058] In response to determining that a mode change from the second mode to the first mode is required, a driver of the controller is controlled to drive a first current on the first data terminal and a second current on the second data terminal, thereby providing a controller mode signal indicating that the transceiver operates in the first mode rather than the second mode.

[0059] According to another aspect, a computer program code is provided, the computer program code being configured to cause a processor of a controller to execute the above method.

[0060] According to another aspect, there is provided a computer program code configured to cause a processor to perform any of the methods disclosed herein.

[0061] According to another aspect of the present disclosure, a computer program code is provided. A non-transitory computer readable medium including the computer program code may be provided. A computer program code configured to cause a processor to perform any method disclosed herein may be provided.

[0062] Although the present disclosure allows for various modifications and alternative forms, the details of the present disclosure have been shown in the drawings by way of example and will be described in detail. However, it should be understood that other embodiments other than the specific embodiments described may also exist. All modifications, equivalents and alternative embodiments falling within the spirit and scope of the appended claims are also encompassed.

[0063] The above discussion is not intended to represent every example embodiment or every implementation within the scope of the current or future claim sets. The following figures and detailed description also illustrate various example embodiments. Various example embodiments can be more fully understood by considering the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] One or more embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0065] Figure 1a An example schematic block diagram of a controller area network (CAN) is shown;

[0066] Figure 1b Shows Figure 1a An example schematic block diagram of a node on a CAN;

[0067] Figure 2 An example schematic diagram showing signals on a CAN XL bus;

[0068] Figure 3 shows an example state diagram illustrating modes of a CAN transceiver;

[0069] Figure 4 A node including a controller and a transceiver is shown;

[0070] Figure 5 shows a schematic block diagram of a node having a CAN XL transceiver operating in FAST-RX mode;

[0071] Figure 6A CAN bus voltage signal, a corresponding signal provided at a first data terminal and a second data terminal of a CAN transceiver, and a corresponding received data signal obtained by a controller are shown;

[0072] Figure 7 shows a schematic block diagram of an embodiment of a node illustrating current flow between a controller and a transceiver during a FAST-RX mode;

[0073] Figure 8 A schematic diagram showing signals on a CAN XL bus similar to those previously described in reference Figure 2 As described, the first data terminal and the second data terminal have corresponding differential signals;

[0074] Fig. 9 A flow chart showing a method for operating a controller;

[0075] Fig.10 A schematic diagram showing an output driver of a transceiver for FAST-RX mode;

[0076] Fig.11 Additional circuitry for the SLOW mode of operation is shown;

[0077] Fig.12 A schematic block diagram of a repeater unit provided at each of a first data terminal and a second data terminal for FAST-TX mode is shown; and

[0078] Fig.13 A schematic block diagram of units provided at each of the first data terminal and the second data terminal for the FAST-RX mode is shown. DETAILED DESCRIPTION

[0079] The proposed CAN XL frame provides a plurality of modes including a SLOW mode that is backward compatible with the conventional CAN, and in order to provide an increased data rate, the modes include a fast transmission mode (FAST-TX) and a fast reception mode (FAST-RX).

[0080] References herein to a CAN transceiver or a CAN controller may be understood as a controller and a transceiver that at least partially implements all or part of the CAN protocol or all or part of the CAN FD protocol. The functionality described herein for a CAN transceiver or a CAN controller may include greater functionality than currently defined in the CAN protocol.

[0081] Figure 1aAn example schematic block diagram of a controller area network (CAN) 100 is shown including a plurality of CAN devices or nodes 102a-d each coupled to a CAN bus 104. The CAN bus 104 includes two signal lines for transmitting differential signals between the plurality of CAN devices 102a-d.

[0082] Figure 1b 1 shows a schematic block diagram of a CAN device 102 coupled to a CAN bus 104. The CAN device 102 includes a CAN controller 106 and a CAN transceiver 108. The CAN controller 106 may be implemented by a processor, such as a microprocessor, that is configured to implement a CAN operating protocol within the CAN network 100. The CAN transceiver 108 interfaces the CAN controller 106 with the CAN bus 104. In some examples, the CAN transceiver 108 may operate without or with limited circuitry for understanding or implementing the CAN protocol, and thus the power consumption of the CAN transceiver 108 may be relatively limited compared to the processor of the CAN controller 106.

[0083] The CAN controller 106 has a first data terminal 114 and a second data terminal 116. The CAN transceiver 108 has a first data terminal 118, a second data terminal 120 and a bus terminal 122, which may also be referred to as a bus port. The bus terminal 122 is coupled to two signal lines of the CAN bus 104. The transmitter output 114 of the CAN controller 106 is coupled to the first data terminal 118 of the CAN transceiver 108. The second data terminal 116 of the CAN controller 106 is coupled to the receive output 120 of the CAN transceiver 108.

[0084] The CAN transceiver 108 includes a transmitter unit 110 and a receiver unit 112 .

[0085] The transmitter unit 110 has an input coupled to a first data terminal 118 of the CAN transceiver 108 and an output connected to a CAN bus terminal 122 of the CAN transceiver 108. The transmitter unit 110 is configured to convert data received at the first data terminal 118 of the CAN transceiver 108 into a differential signal for the CAN bus 104.

[0086] The transmitter unit 110 includes at least one transmitter. The at least one transmitter is configured to operate in a first transmission mode or a second transmission mode. In the first transmission mode, the transmitter arrangement is configured to transmit the signaling having a first characteristic, and in the second transmission mode, the transmitter arrangement is configured to transmit the signaling having a second characteristic. The first characteristic and the second characteristic may include one or more characteristic types, such as baud rate (e.g., maximum, minimum or average baud rate), voltage level scheme, encoding scheme or other. However, for ease of description herein, the first characteristic and the second characteristic may include baud rate, so that the first characteristic includes a first baud rate and the second characteristic includes a second baud rate, wherein the first baud rate is higher than the second baud rate. Using a higher baud rate can increase the rate at which data can be transmitted on the CAN bus. However, it should be understood that the first characteristic and the second characteristic may (in any example embodiment herein) alternatively or additionally be a voltage level scheme for representing logic 0 and logic 1 on the CAN bus 102.

[0087] Therefore, further and by way of example only, the first transmission mode may be referred to as a fast transmission mode (FAST-TX) and the second transmission mode may be referred to as a slow transmission mode (SLOW-TX).

[0088] For example, in FAST-TX mode, the controller drives current on the first data terminal and the second data terminal using differential encoding to provide received data. In SLOW-TX mode, the controller sends a signal to the transceiver using only the first data terminal to provide received data.

[0089] Receiver unit 112 has an input coupled to CAN bus terminal 122 and outputs coupled to first data terminal 118 and second data terminal 120 of CAN transceiver 108 Receiver unit 112 is configured to convert a differential signal on CAN bus 104 into receive data for CAN controller 106 .

[0090] The receiver unit 112 includes at least one receiver. The at least one receiver may be configured to operate in a first receiving mode or a second receiving mode, wherein in the first receiving mode, the receiver unit 112 is configured to receive signaling having a first characteristic from the bus 102, and in the second receiving mode, the receiver unit 112 is configured to receive signaling having a second characteristic from the bus 102. As described above, the characteristic may be any one or more of a baud rate, a voltage level scheme, an encoding scheme, or others.

[0091] Therefore, further and by way of example only, the first reception mode may be referred to as a fast reception mode (FAST-RX) and the second reception mode may be referred to as a slow reception mode (SLOW-RX).

[0092] For example, in FAST-RX mode, the transceiver drives current on one of the first data terminal and the second data terminal using differential encoding to provide received data. In SLOW-RX mode, the transceiver only uses the second data terminal to send a signal to provide received data.

[0093] Therefore, the first data end and the second data end can be regarded as providing bidirectional data transmission in the FAST data mode.

[0094] Figure 2 A schematic diagram of a signal 200 on a CAN XL bus for providing relatively high-speed data communication in a CAN network is shown. Two different voltage level schemes in a CAN XL frame are shown. The signal 200 provides a simplified CAN frame 201. The simplified CAN frame 201 includes an excerpt representing an arbitration phase 203, 205 (in SLOW mode) and an excerpt representing a data phase 207 (in FAST mode). The valid signal levels in the arbitration phase 203, 205 can be defined according to ISO 11898-2:2016. The data phase 207 contains data at CAN XL levels, as discussed further below. In a practical example, the data phase 207 can be substantially longer than the arbitration phase 203, 205 and can include, for example, 2048 data bytes. Specifically, the level of the signal in the arbitration phase can be used to indicate whether a particular node can access the bus system through a CAN-defined arbitration method using dominant and recessive bus driver levels and corresponding receiver thresholds.

[0095] The CAN XL transceiver is to support three different threshold levels. The first threshold (Th1) is approximately the well-known ISO11898-2:2016 standard level between +0.5V and +0.9V differential, used for backward compatible CAN arbitration.

[0096] The second threshold (Th2) is associated with fast CAN XL data communication of approximately 0V differential and has a minimum level of -0.1V and a maximum level of +0.1V.

[0097] The third threshold (Th3) is used to reliably detect the presence of fast CAN XL data communication on the bus line by a threshold in the negative differential region, and the maximum level of the third threshold (eg, -0.3V . . . -0.4V) is lower than the minimum level of the second threshold.

[0098] During the arbitration phase (SLOW), it is decided whether a particular node on the network will become dominant and enter FAST-TX mode, or become recessive and enter FAST-RX mode.

[0099] Figure 3A state diagram of the operating modes of a CAN XL node is shown. The controller and transceiver of the node can each be considered to operate in one of the specific modes. As previously described, the modes include a first mode (SLOW) 301, a second mode (FAST-RX) 302, and a third mode (FAST-TX) 303. The CAN scheme allows for multiple transitions between system states. Specifically, a node can transition 306 from a first mode 301 to a second mode 302. A node can transition 307 from a second mode 302 to a first mode 301. A node can transition 304 from a first mode 301 to a third mode 303. A node can transition 305 from a third mode 303 to a first mode 301. In introducing Figures 4 to 10 After introducing the concepts in Figure 3 The conditions for the various transformations are marked above.

[0100] In order to ensure proper operation of the CAN network, it is necessary to synchronize the operating state or mode of each node in the network. For example, as previously described, only one node can operate in FAST-TX mode on the network at any one time during the data phase, while other nodes on the network should operate in FAST-RX mode in order to ensure proper communication.

[0101] As previously described with respect to FIG. 1 , the transceiver needs to modify its operating parameters in various modes. However, the transceiver is typically implemented in a relatively simplified form in order to reduce cost, complexity, and power consumption, and therefore the transceiver is typically implemented without knowledge of the working protocol. Therefore, the transceiver itself may not detect the requirement for a change in the operating mode of the node. To address this issue, a controller may monitor data to determine that a mode change is required, and then the controller signals the transceiver that a mode change is required.

[0102] Changing modes may be necessary for a number of reasons, for example due to:

[0103] i. The planned end of the FAST data phase;

[0104] ii. in response to detecting erroneous data in the data signal, for example due to a collision on a bus; or

[0105] iii. After initialization (for example, if the controller's microcontroller is reset after a brown-out while the transceiver is still in FAST mode) to ensure that the transceiver is in SLOW mode before the transmission of a CAN frame starts.

[0106] Figure 44 shows a node including a controller 406 and a transceiver 408. In this example, the controller 406 and the transceiver 408 each have dedicated pins 436, 438 to enable the controller 406 to provide a controller mode signal to instruct the transceiver 408 to operate in a particular mode. In other respects, the node 400 can be viewed as similar to the previously described node 400. Figure 1b The node being described.

[0107] It should be understood that if Figure 4 The implementation for providing the controller mode signal using a dedicated pin in the example of FIG increases the external circuit complexity due to the need for an additional interface line between the controller 406 and the transceiver 408. In many CAN applications, the number of pins that can be implemented is limited. In fact, for some applications, CAN transceivers have a standardized package layout that cannot directly support the provision of additional lines.

[0108] The difficulties encountered in providing dedicated signaling pins can be overcome by instead using the existing first and second data terminals to provide the controller mode signal of the controller to the transceiver. However, such implementations raise their own technical challenges.

[0109] Different signals can be used by Figure 3 The various mechanisms for the various transformations shown in are provided. For example, a signal may be sent to notify a transformation from a first mode (SLOW) to a third mode (FAST-TX) by providing a positive pulse on a first signal terminal (TRXD0 (txd)) driven by a CAN controller. In another example, a signal may be sent to notify a transformation from a first mode (SLOW) to a second mode (FAST-RX) by providing a negative pulse on a first signal terminal (TRXD0 (txd)) driven by a CAN controller. In the introduction of reference Figures 4 to 10 After discussing the concepts, the following will discuss in more detail Figure 3 Additional mode change conditions are shown in .

[0110] In the context of the CAN XL system, the following references Figures 5 to 8 The specific example discussed involves using the first data terminal and the second data terminal to provide a controller mode signal that instructs the transceiver to change from the second mode (FAST-RX) to the first mode (SLOW).

[0111] Figure 5 A schematic block diagram of a node 502 with a CAN XL transceiver operating in a second (FAST-RX) mode is shown. The node 502 includes a controller 506 and a transceiver 508.

[0112] The transceiver 508 includes a first driver 542 coupled to the first data terminal 518. The transceiver 508 also includes a second driver 544 coupled to the second data terminal 520. In the second mode, in normal operation where data is being transmitted from the transceiver 508 to the controller 506, the transceiver 508 provides received data to the controller 506 using both the first data terminal 518 and the second data terminal 520.

[0113] The first data terminal 518 of the transceiver 508 is coupled to the first data terminal 514 of the controller 506. The second data terminal 520 of the transceiver 508 is coupled to the second data terminal 516 of the controller 506.

[0114] The controller 506 includes a first receiver stage 546 coupled to the first data terminal 514. The controller 506 includes a second receiver stage 548 coupled to the second data terminal 516. In this example, the first receiver stage 546 and the second receiver stage 548 are provided by Schmitt triggers.

[0115] For reference Figure 6 The normal operation of node 502 is better understood.

[0116] Figure 6 A CAN bus voltage signal 601 , corresponding signals 602 , 603 provided at the first data terminal and the second data terminal, respectively, and a corresponding received data signal 604 obtained by the controller are shown.

[0117] The transceiver 508 drives the signals on the first data terminal 518 and the second data terminal 520 out of phase with each other using the first driver 542 and the second driver 544 .

[0118] The loads on the first data terminal and the second data terminal are purely capacitive, so current needs to be driven to or from the corresponding terminals in order to increase or decrease the signal level on each terminal. That is, the output characteristics of the first data terminal and the second data terminal are such that they can be used with relatively high current (I 强 ) and use the limited lower current (I 弱 ) or vice versa. Current can be driven high or low, that is, it can be driven in either direction, and the rate at which the signal level changes between high and low levels depends on whether the current driven to the corresponding terminal is weak or strong. Strong currents are greater than weak currents, and the terms "weak" and "strong" are used relative to each other.

[0119] exist Figure 6 In the example shown in , the signal at the terminal is driven from high to low by applying a strong current, while the signal is driven from low to high using a weak current. The strong drive current is required to meet the requirements of appropriately fast switching.

[0120] During the second (FAST-RX) mode, data from the CAN transceiver may be encoded out of phase on the first data terminal (TRXD0 pin) pin and in phase on the second data terminal (TRXD1 pin). Alternatively, during the second (FAST-RX) mode, data may be encoded in phase on the first data terminal (TRXD0 pin) pin and out of phase on the second data terminal (TRXD1 pin). The data is decoded back in the controller by triggering on the edge of the first data terminal (TRXD0 pin) or the second data terminal (TRXD1 pin). For example, a negative edge on the first data terminal (TRXD0 pin) decodes to data zero, while a negative edge on the second data terminal (TRXD1 pin) decodes to data one. A positive edge has no effect on the decoding process. That is, the transition of the data can be detected based on the falling edge in the signal and the first and second data terminals. Specifically, the falling edge on the signal 602 at the first data end indicates a falling edge in the received data determined by the controller 506, and the falling edge on the signal 603 at the second data end indicates a rising edge in the received data determined by the controller 506. Of course, alternatives are also possible, wherein the positive edge triggers the data change and the negative edge is ignored. As described with reference to Figure 1, in the second (FAST-RX) mode, the first mode end and the second data end are used as two bidirectional logic pins, wherein the data are represented by opposite logic levels. Since differential encoding is used for the signals on the first mode end and the second data end in the second mode, the ramp time of the rising edge on the first data end and the second data end (TRXD0, TRXD1) is not important for timing symmetry.

[0121] This means that if the CAN controller needs to change to the first (SLOW) mode, the mode change can be indicated to the transceiver by driving both the first data terminal and the second data terminal to a low level using a strong current output driver that is able to overcome the weak pull-up current of the transceiver that produces a low signal. This indication of a mode change does not depend on the voltage level on the CAN bus, as may be the case with some alternative solutions.

[0122] Return to Figure 5 , the controller 506 further includes a first driver 550 coupled to the first data terminal 514 and a second driver 552 coupled to the second data terminal 516. The transceiver 508 includes a first receiver stage 554 coupled to the first data terminal 518 and a second receiver stage 556 coupled to the second data terminal 520.

[0123] The controller 506 is configured to provide a controller mode signal by driving current on the first data terminal and the second data terminal using the first driver 550 and the second driver 552, the controller mode signal indicating that the transceiver 508 operates in the first mode rather than the second mode. The additional current provided by the controller 506 interacts with the current applied by the first driver 542 and the second driver 544 of the transceiver, which are related to the received data level. As a result, the voltage level at the first terminal or the second terminal can be changed by the controller 506 to provide a controller mode signal that can be detected by the receiver stage 554, 556 of the transceiver 508. The transceiver is configured to monitor the first data terminal and the second data terminal for the controller mode signal in the second operating mode, and change the mode from the second mode to the first mode based on detecting the controller mode signal.

[0124] Switching from the second (FAST-RX) mode to the first (SLOW) mode by driving the first data terminal and the second data terminal to the same logic level produces an unconditional mode change that enables predictable detection. In this way, the proposed signaling scheme can provide a robust method for providing a controller mode signal to a transceiver.

[0125] According to another example of a CAN node having a CAN controller, the CAN controller is configured to provide a controller mode signal - to switch the CAN transceiver from the second operation mode to the first operation mode.

[0126] The controller includes a first data terminal for communicating with the transceiver; and a second data terminal for communicating with the transceiver. The controller is configured to:

[0127] in the second mode, determining received data based on a signal at the first data end and a signal at the second data end;

[0128] determining that a mode change from the second mode to the first mode is required; and

[0129] In response to determining that a mode change from the second mode to the first mode is required, providing a controller mode signal indicating that the transceiver operates in the first mode rather than the second mode, wherein the controller mode signal is provided by simultaneously driving a first current on the first data terminal and a second current on the second data terminal.

[0130] The transceiver includes: at least one bus terminal for communicating with a network bus; a first data terminal for communicating with the controller; a second data terminal for communicating with the controller; and a receiver. The first data terminal of the transceiver is connected to the first data terminal of the controller. The second data terminal of the transceiver is connected to the second data terminal of the controller. The receiver is configured to generate reception data for the controller based on a bus signal received at at least one bus terminal in a second mode. The reception data is provided by the transceiver driving a first current on the first data terminal and driving an opposite second current to the second data terminal. The transceiver is configured to monitor whether there is a controller mode signal at the first data terminal and the second data terminal in the second operating mode. The controller mode signal is provided by the first data terminal and the second data terminal being the same logic level caused by the controller applying at least one of the first current and the second current. The transceiver is further configured to change the mode from the second mode to the first mode based on the detection of the controller mode signal.

[0131] The same method of signaling between the controller and the transceiver may be used to provide a controller mode signal that provides a transition from the third (FAST-TX) mode to the first (SLOW) mode.

[0132] In such examples, the controller may be additionally configured to:

[0133] in the third operating mode, using the signal at the first data terminal and the signal at the second data terminal to provide transmission data;

[0134] In response to determining that a mode change from the third mode to the first mode is required, providing a controller mode signal indicating that the transceiver operates in the first mode instead of the third mode, wherein the controller mode signal is provided by simultaneously driving a first current on the first data terminal and a second current on the second data terminal. The transmission data may be encoded as a differential signal provided at the first data terminal and the second data terminal of the controller.

[0135] In such examples, the transceiver may further include a transmitter configured to receive transmission data for the controller in a third mode and generate a bus signal for the at least one bus terminal based on the transmission signal, wherein the transmission data is provided by the controller at the first first data terminal and the second data terminal as a differential signal. The transceiver is configured to:

[0136] In the third operation mode, monitoring the first data terminal and the second data terminal for a controller mode signal indicating a need to change a mode from the third mode to the first mode, wherein the controller mode signal is provided by a logic level at the first data terminal being the same as a logic level at the second data terminal; and

[0137] A mode is changed from the third mode to the first mode based on detecting the controller mode signal.

[0138] See below for reference Figure 7 and 8 With the described examples, operation of the controller to provide the controller mode signal in the second mode of operation may be better understood.

[0139] Figure 7 Schematic block diagram of an embodiment of a node 702 showing current flow between a controller 706 and a transceiver 708 during a second mode of operation is shown. Figure 5 and 7 Between controllers and about Figure 1b Corresponding reference numerals are used.

[0140] As previously referenced Figure 6 As shown, when a LEVEL1 signal known in CAN terminology is present on the CAN bus 722, the receiver 712 of the transceiver 708 controls the first driver 742 of the transceiver 708 to provide a strong inflow current to the first data terminal 718 and controls the second driver 744 of the transceiver 708 to provide a weak outflow current to the second data terminal 720. For the avoidance of doubt, the term "inflow current" as used herein means a current having a current direction of flowing into a driving device, and the term "outflow current" as used herein means a current having a current direction of flowing out of a driving device.

[0141] When the signal of the CAN bus is at logic LEVEL0, the receiver 712 of the transceiver 708 controls the first driver 742 of the transceiver 708 to provide a weak outgoing drive current to the first data terminal 718 and controls the second driver 744 of the transceiver 708 to provide a strong ingoing current to the second data terminal 720.

[0142] In response to determining within the controller 706 that a mode change from the second mode to the first mode is required, the controller 706 controls the first and second drivers 750 , 752 to drive a strong inflow current at the respective first and second data terminals 714 , 716 .

[0143] References below Figure 8 The effect of the additional high current imposed by the first and second drivers 750 , 752 of the controller 706 is further described.

[0144] Figure 8 A schematic diagram of a signal 800 on a CAN XL bus is shown, the signal 800 being similar to the previously described signal 800 of FIG. Figure 2 As described, the first data terminal and the second data terminal have corresponding differential signals 802 and 804. As previously referred to Figure 2 As depicted, the signal includes a portion representing the application of arbitration phases 803, 805 (in the first (SLOW) mode) and a portion representing the data phase 807 (in the second (FAST-RX) mode).

[0145] In the first arbitration phase 805, the CAN controller transmits a single short low pulse on the first data terminal (TRXD0 pin) which is detected by the transceiver, and then switches from the first (SLOW) mode to the second (FAST-RX) mode in the data phase 807. The second data terminal (TRXD1 pin) switches from the output configuration in the first (SLOW) mode to the input configuration in the second (FAST-RX) mode. According to the differential signaling scheme adopted in the second operating mode, when transitioning to the data phase 807, the signal 802 at the first data terminal is out of phase with the signal 804 at the second data terminal. When transitioning 862 from the data phase 807 to the arbitration phase 803, the controller drives both the first data terminal and the second data terminal so that the signals 802, 804 at the first data terminal and the second data terminal are both low at the same time, thereby providing a special condition in the second mode. The special condition is used by the controller and the transceiver as a controller mode signal.

[0146] The CAN controller transmits a single short negative pulse detected by the transceiver simultaneously on both the first data terminal (TRXD0 pin) and the second data terminal (TRXD1 pin) in period 862, and then switches from the second (FAST-RX) mode to the first (SLOW) mode. Since the first data terminal (TRXD0 pin) and the second data terminal (TRXD1 pin) are always inverted during the second (FAST-RX) mode, the short negative pulse on both the first data terminal (TRXD0 pin) and the second data terminal (TRXD1 pin) provides a unique condition that can be detected as an indication of changing the mode to the first (SLOW) mode. Alternatively, the pulse can be a single short positive pulse on both the first data terminal (TRXD0 pin) and the second data terminal (TRXD1 pin), which is also a unique condition. In either case, the controller is configured to provide a controller mode signal in which the voltage levels on the first data terminal and the second data terminal are in the same logic state (which can be logic high or logic low) by driving both the first data terminal and the second data terminal with current of the same polarity.

[0147] In this example, when the level of signal 802 at the first data end is limited by the controller and the level of signal 804 at the second data end is related to the state of data on the CAN bus, time period 864 at the beginning of arbitration phase 803 provides a controller mode signal, and then the node starts transmitting in time period 866 of arbitration phase 803.

[0148] Return to Figure 7 , in this example, the transceiver 708 is capable of monitoring the signal levels at the first data terminal 718 and the second data terminal 720 using corresponding first and second receiver stages 754, 756. In this example, the first and second receivers 754, 756 are provided by Schmitt triggers. The outputs from the first and second receiver stages 754, 756 are provided to an exclusive OR (XOR) gate 760. In this way, the transceiver 708 can detect when the signals at the first data terminal and the second data terminal 720 are at the same logic level, which indicates a special condition in the second mode operation. In this example, this special condition is used to provide a controller mode signal indicating that a mode change from the second mode to the first mode is required.

[0149] It should be appreciated that the control logic of the controller and transceiver may be implemented by either: i) hardware or ii) hardware and software.

[0150] In some examples, only hardware may be used, such as using the Figure 8 The described XOR gate is used to implement the controller mode signal detection in the transceiver. For example, if the signals from the first data terminal and the second data terminal are inverted, an exclusive-OR (XNOR) operation can be performed as an alternative to the XOR operation.

[0151] In some examples, the logic of the controller may be implemented by a data processor. Fig. 9 A flow chart of a method 900 for operating a controller is shown. The method 900 comprises:

[0152] In a second mode, determining 902 received data based on a signal at a first data terminal and a signal at a second data terminal of the controller;

[0153] determining 904 that a mode change from said second mode to a first mode is required; and

[0154] In response to determining that a mode change from the second mode to the first mode is required, controlling 906 a driver of the controller to drive a first current on the first data terminal and a second current on the second data terminal, thereby providing a controller mode signal indicating that the transceiver operates in the first mode rather than the second mode.

[0155] The pin is driven strong low only by the CAN controller, or strong low or weak high by the transceiver, and the result is always low, regardless of the voltage level on the bus.

[0156] Fig.10 FIG. 1 shows a schematic diagram of an output driver for a transceiver for the second (FAST-RX) mode. For example, the output driver may be used Figure 7 transceiver.

[0157] The output drivers 1042, 1044 have a strong inflow driver 1073 and a weak outflow driver 1071. Alternatively, depending on the encoding scheme selected, a strong outflow driver and a weak inflow driver may be provided instead.

[0158] The strong inflow driver 1073 includes a first switching unit 1074 and an inverter driver. In this example, the first switching unit 1074 is provided by a field effect transistor. Alternatively, the first switching unit 1074 can be provided by a bipolar transistor. The output from the receiver is provided to the inverter driver 1072 as a switching signal. The output of the inverter 1072 is provided to the control input of the switching unit 1074. The conductive channel of the switching unit 1074 is coupled between the data terminal of the transceiver and the ground.

[0159] The weak outgoing driver 1071 includes a current source (I 上拉 ) 1076 and the second switching unit 1070. For example, the second switching unit 1074 may be provided by a bipolar transistor or a field effect transistor. The output from the receiver is provided to the second switching unit 1070 as a switching signal. The current source (I 上拉 ) 1076 is arranged to be connected in series with the conductive path of the second switching unit 1070 between the voltage source (VIO) of the transceiver and the data terminals 1018, 1020 of the transceiver.

[0160] The output driver configuration of the transceiver with a weak outgoing driver and a strong incoming driver enables the controller to drive both the first data terminal and the second data terminal to a low logic level without generating a large short circuit current. Alternatively, a weak incoming current and a strong outgoing current are used as drivers in the transceiver, and driving both the first data terminal and the second data terminal to a high logic level to signal a mode change is also a working solution. In this case, the bits of the received data can be encoded by making the signal edge rise.

[0161] Example specifications for weak pull-up current are provided below.

[0162] Assumptions:

[0163] During the rising period in the second mode, t RISE_FASTRX <50ns,

[0164] Supply voltage, V VIO =5V,

[0165] The capacitance at the first / second data terminal, C TRXD <25pF

[0166] but

[0167] Minimum pull-up current, I PULLUP_MIN =25p*0.8*5 / 50n=2mA

[0168] Assumptions

[0169] The falling signal edge period in the second mode, t FALL_F2S <50ns,

[0170] Supply voltage, V VIO =5V,

[0171] The capacitance at the first / second data terminal, C TRXD <25pF,

[0172] Then, the minimum current specification of the controller's output driver, I GPIO_MIN =10mA

[0173] but

[0174] Maximum pull-up current, I PULLUP_MAX =I GPIO_MIN -25p*0.8*5 / 50n=8mA

[0175] In integrated chip technology, current source specifications between 2 mA and 8 mA can be easily implemented.The value of the strong current supplied by the driver of the controller can be higher, for example, above 10 mA.

[0176] Return to Figure 3 It should be noted that a plurality of conditions for various transitions 304-307 between modes are labeled. As previously described, the modes include a first mode (SLOW) 301, a second mode (FAST-RX) 302, and a third mode (FAST-TX) 303.

[0177] The low logic level pulse provided at the first data terminal has a period t TRXD0_LOW , and the high logic level pulse provided at the first data terminal has a period t TRXD0_HIGH Similarly, the low logic level pulse provided at the first data terminal has a period t TRXD0_LOW , and the high logic level pulse provided at the first data terminal has a period t TRXD0_HIGH .

[0178] In this example, a node may transition 306 from a first mode 301 to a second mode 302 if:

[0179] t TOFAST_MIN <t TRXD0_LOW <t TOFAST_MAX .

[0180] That is, if the low pulse at the first signal terminal has a minimum transition period t TOFAST_MIN With the maximum change period t TOFAST_MAX The duration between the low pulses acts as a controller mode signal. Minimum switching period t TOFAST_MIN Used as a threshold to prevent mode changes based on very small disturbances on the first data terminal (TRXD0 pin). Maximum changeover period t TOFAST_MAX Used as threshold to prevent mode changes based on normal CAN FD.

[0181] The node may transition 304 from the first mode 301 to the third mode 303 if:

[0182] t TOFAST_MIN <t TRXD0_HIGH <t TOFAST_MAX .

[0183] A node may transition 307 from the second mode 302 to the first mode 301 if:

[0184] t TRXD0_LOW >t TOSLOW ;and

[0185] t TRXD1_LOW >t TOSLOW , where t TOSLOW is the threshold used to identify pulses.

[0186] The node may transition 305 from the third mode 303 to the first mode 301 if:

[0187] t TRXD0_LOW >t TOSLOW ;and

[0188] t TRXD1_LOW >t TOSLOW .

[0189] Examples of pulse length specifications are:

[0190] t TOFAST <t CANFD_MAX ;

[0191] Max CANFD 8Mbps: t TOFAST <125ns;

[0192] 90ns<t TOFAST <110ns;

[0193] t TOSLOW <(t ARBMIN / 2-t FALL_F2S );

[0194] Max ARB 1Mbps;

[0195] t ARBMIN ≥1μs;

[0196] t FALL_F2S <50ns;

[0197] t TOSLOW <450ns;

[0198] 90ns<t TOSLOW <110ns.

[0199] One way for the controller to generate short TXD pulses used as controller mode signals is to use the controller's existing time quantum mechanism. That is, bits are divided into separate time slots (time quanta) and used by the CAN controller to define specific protocol aspects such as resynchronization zones and sample points. These time quanta can also be used to generate defined short pulses.

[0200] Figures 11 to 13 Additional circuitry for various operating modes is shown that may be provided in a transceiver at the first data terminal and the second data terminal.

[0201] Fig.11 Additional circuitry is shown for a first (SLOW) mode of operation.In the first mode, a transmitter of the transceiver converts data received at a first data terminal into a differential signal for a CAN bus.

[0202] A first data end repeater unit 1180 is provided at the first data end 1118 for use in the first mode. The repeater unit 1180 includes:

[0203] a forward path receiver 1181 provided by a Schmitt trigger between the first data terminal 1118 and the input 1184 of the transmitter; and

[0204] A feedback path comprising a series arrangement of a weak current driver 1182 followed by an impedance 1183 (a 10 kilo-ohm resistor in this example) from the input 1184 of the transmitter to the first data terminal 1118 .

[0205] A second data end repeater unit 1185 is also provided at the second data end 1120 for use in the first mode. The second data end repeater unit 1185 comprises:

[0206] a forward path receiver 1189 provided by a Schmitt trigger between the second data terminal 1120 of the receiver and the input 1188; and

[0207] A feedback path comprising a series arrangement of a weak current driver 1186 followed by an impedance 1187 (a 10 kilo-ohm resistor in this example) from the input 1188 of the receiver to the second data terminal 1120 .

[0208] The first data terminal (TRXD0) of the transceiver in the first (SLOW) mode is an input pin. The repeater configuration prevents undefined levels in the event of a fault mode where the CAN controller is in error mode and also has its first data terminal (TRXD0 pin) as an input, and neither the controller nor the transceiver drives the pin. The impedance acts as a high-impedance pull-up or pull-down, depending on the previously received logic level. When the pin becomes floating, it will hold the last known logic state.

[0209] The output driver 1191 of the receiver is coupled to the second data terminal 1120. The output driver is configured to provide a strong output current when enabled. The output driver has a maximum active pulse time provided by a fixed timer 1192. In this way, the second data terminal repeater unit 1185 provides a driver that drives the output for a fixed time triggered by a change on its input, and after the fixed time has passed, the output is in a high impedance, three-state.

[0210] The second data terminal (TXRD1) 1120 of the transceiver in the first (SLOW) mode is in an output pin and an input (repeater) pin. The output driver 1191 is in a tri-state condition during the static state, and the logic level at the second data terminal (TXRD1) 1120 is defined by the repeater through impedance, which is provided by the pull-up / pull-down resistor. In the case where the output driver 1191 is driving current to change the output level at the second data terminal (TXRD1) 1120, the strong driver is only active for a fixed period defined by the fixed timer 1192, which is triggered by both rising and falling edges (on the network "output (out)"). Providing a fixed timer on the driver prevents long short currents from occurring when a fault mode occurs, when the CAN controller is in an error mode and is still driving the second data terminal (TRXD1 pin).

[0211] The duration of the fixed timer period may depend on the current drive strength and the capacitive load present on the second data terminal. The minimum value of the fixed time may be greater than the maximum ramp time. For example:

[0212] Assume that

[0213] The minimum drive strength is 10mA.

[0214] The power supply voltage is 5V,

[0215] Capacitive load is 25pF

[0216] but

[0217] The maximum ramp time is 25p*5 / 10m=12.5ns

[0218] therefore

[0219] The minimum period of time is greater than 12.5 ns.

[0220] Fig.12 A schematic block diagram of a repeater unit 1280 provided at each of the first data terminal 1218 and the second data terminal 1220 for the third (FAST-TX) mode is shown. That is, both the first data terminal and the second data terminal (TRXD0 / 1 pin) are in repeater mode during the third (FAST-TX) mode. Each repeater unit 1280 includes:

[0221] a forward path receiver 1281 provided by a Schmitt trigger between the first data terminal 1218 or the second data terminal of the transmitter and the input 1284; and

[0222] A feedback path comprising a series arrangement of a weak current driver 1282 followed by an impedance 1283 (a 10 kilo-ohm resistor in this example) from the input 1284 of the transmitter to either the first data terminal 1218 or the second data terminal.

[0223] Fig.13 A schematic block diagram of a unit 1380 provided at each of the first data terminal 1318 and the second data terminal 1320 for the second (FAST-RX) mode is shown. The unit 1380 comprises a driver stage 1342, 1344 and a receiver stage 1354, 1356.

[0224] Driver stages 1342, 1344 and receiver stages 1354, 1356 correspond to those described in the previous reference. Figure 7 A driver stage and a receiver stage are provided at any one of the first data terminal and the second data terminal described.

[0225] In this example, the receiver stages 1354, 1356 are provided by Schmitt triggers. Alternatively, the Schmitt triggers may be provided by, for example, Fig.12 The described repeater arrangement is substituted.

[0226] The internal configuration of driver stages 1342, 1344 is similar to that of previously referenced Fig.10 Same as described.

[0227] In the second (FAST-RX) mode, both the first data terminal 1318 and the second data terminal 1320 (TRXD0 / 1 pins) are used as outputs of the transceiver, and the receiver stage allows the transceiver to detect the controller mode signal.

[0228] It should be understood that reference Figures 11 to 13 The described circuit system can be used with reference to, for example, Figure 5 and 7 Alternatively, the transceiver combination described herein is provided. Figures 11 to 13 The described circuitry may be provided in combination with a CAN transceiver, including a CAN FD transceiver.

[0229] Unless a specific order is explicitly stated, the instructions and / or flow chart steps in the above figures may be executed in any order. Moreover, those skilled in the art will recognize that although an example instruction set / method has been discussed, the materials in this specification may be combined in a variety of ways to produce other examples and should be understood within the context provided in this detailed description.

[0230] In some example embodiments, the instruction set / method steps described above are implemented as functions and software instructions embodied as an executable instruction set, which is implemented on a computer or a machine programmed with and controlled by the executable instructions. Such instructions are loaded for execution on a processor (e.g., one or more CPUs). The term processor includes a microprocessor, a microcontroller, a processor module or subsystem (including one or more microprocessors or microcontrollers), or other control or computing devices. A processor may refer to a single component or multiple components.

[0231] In other examples, the instruction sets / methods shown herein and the data and instructions associated therewith are stored in corresponding storage devices, which are implemented as one or more non-transitory machine or computer readable or computer usable storage media. Such computer readable or computer usable storage media are considered to be part of an article (or product). An article or product may refer to any manufactured single component or multiple components. A non-transitory machine or computer usable medium as defined herein does not include signals, but such a medium is capable of receiving and processing information from signals and / or other transient media.

[0232] Example embodiments of the materials discussed in this specification may be implemented in whole or in part through network, computer or data-based devices and / or services. These may include the cloud, the Internet, an intranet, a mobile device, a desktop computer, a processor, a lookup table, a microcontroller, a consumer device, an infrastructure, or other enabling devices and services. As may be used herein and in the claims, the following non-exclusive limitations are provided.

[0233] In one example, one or more instructions or steps discussed herein are automated. The term automation or automatic (and similar variations thereof) means the use of computers and / or mechanical / electrical devices to control the operation of a device, system, and / or process without human intervention, observation, effort, and / or decision making.

[0234] It should be understood that any components that are said to be coupled may be coupled or connected directly or indirectly. In the case of indirect coupling, additional components may be placed between the two components that are said to be coupled.

[0235] In this specification, example embodiments have been presented based on a selected set of details. However, one of ordinary skill in the art will appreciate that many other example embodiments including different selected sets of these details may be practiced. It is intended that the appended claims cover all possible example embodiments.

Claims

1. A controller having a first mode and a second mode for communicating with a transceiver in a network node, characterized in that The controller comprises: A first data port for communicating with the transceiver; and a second data terminal for communicating with the transceiver, The controller is configured to: generating a first controller mode signal in a first arbitration phase, the first controller mode signal causing the transceiver to operate in the second mode by driving a first current on the first data terminal and a second current on the second data terminal, wherein the first current and the second current have opposite polarities; In a data transmission phase occurring after the first arbitration phase, transmitting data to the transceiver using a differential signal encoding scheme in which a data value is encoded as a signal by a voltage difference between a first voltage on the first data terminal and a second voltage on the second data terminal; The second arbitration phase occurs after the data transmission phase. determining that a mode needs to be changed from the second mode to the first mode, wherein the first mode includes sending the data to the transceiver using the first data port or the second data port; and A second controller mode signal is generated by simultaneously driving a first current on the first data terminal and a second current on the second data terminal during the second arbitration phase to cause the transceiver to operate in the first mode rather than the second mode, wherein the controller mode signal is provided by simultaneously driving a first current on the first data terminal and a second current on the second data terminal, wherein the first current and the second current have the same polarity.

2. The controller according to claim 1, characterized in that: The controller is further configured to provide the second controller mode signal by driving both the first data terminal and the second data terminal to the same logic state.

3. The controller according to claim 2, characterized in that: The controller is further configured to provide the second controller mode signal by driving both the first data terminal and the second data terminal to a low logic state.

4. A controller according to any preceding claim, characterised in that The controller is a CAN controller.

5. A transceiver having a first mode and a second mode for communicating with a controller and a network bus in a network node, characterized in that: The transceiver comprises: at least one bus terminal for communicating with the network bus; a first data terminal for communicating with the controller; A second data terminal for communicating with the controller, a receiver configured to generate reception data for the controller in the second mode and during a first data transmission phase based on a bus signal received at the at least one bus terminal by determining a differential value, wherein the differential value is generated by the transceiver driving a first current on the first data terminal and driving an opposite second current to the second data terminal; The transceiver is configured to: monitoring the first data terminal and the second data terminal for a controller mode signal indicating a need to change a mode from the second mode to the first mode during an arbitration phase occurring after the first data transmission phase, wherein the controller mode signal is provided by a logic level at the first data terminal being the same as a logic level at the second data terminal for detecting a signal pulse in the second mode; and The mode is changed from the second mode to the first mode based on detecting the controller mode signal to cause the receiver to operate in the first mode in a second data transmission phase, the second data transmission phase occurring after the arbitration phase, wherein the receiver generates reception data for the controller by determining a logic level at the first data terminal or a second data terminal based on a common signal received at at least one common terminal.

6. The transceiver according to claim 5, characterized in that: A first output driver coupled to the first data terminal of the transceiver and a second output driver coupled to the second data terminal of the transceiver are included, wherein each output driver includes a weak outflow driver and a strong inflow driver for providing corresponding first current and second current.

7. A method of operating a controller having a first mode and a second mode for communicating with a transceiver in a network node, characterized in that, The method comprises: In the second mode and in the first data transmission phase, determining received data based on a difference between a signal at a first data terminal and a signal at a second data terminal of the controller; an arbitration phase occurring after the first data transmission phase determines that a mode change from the second mode to the first mode is required; In response to determining that a mode change from the second mode to the first mode is required, controlling a driver of the controller to drive a first current on the first data terminal and a second current on the second data terminal to set a first logic level on the first data terminal equal to a second logic level on the second data terminal for detecting a signal pulse in the second mode, thereby providing a controller mode signal indicating that the transceiver operates in the first mode rather than the second mode; and In the first mode and in a second data transmission phase, reception data is determined based on a logic level of the first data terminal or the second data terminal, wherein the second data transmission phase occurs after the arbitration phase.

8. A computer-readable storage medium, characterized in that: The device is configured to cause the processor to perform the method according to claim 7.

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