TW202520698A - Communication method and communication device - Google Patents

Abstract

The present disclosure relates to a communication method and a communication device that make it possible to avoid collision of same-direction communication on a single physical wire. When second data is input during transmission of first data through a physical layer capable of transmitting a plurality of types of data to/from a communication partner device on a single physical wire, a communication device according to the present disclosure interrupts the transmission and transmits the second data by inserting interrupt control data into the first data. The present disclosure can be applied to, for example, a communication system to which an in-vehicle camera is connected.

Description

Communication method and communication device

The present disclosure relates to a communication method and a communication device, and more particularly to a communication method and a communication device capable of avoiding conflicts in same-direction communications in a physical wiring.

One of the specifications defined by the MIPI (Mobile Industry Processor Interface) Alliance is the A-PHY (Automotive PHY) specification (see, for example, non-patent document 1). A-PHY is a specification for the physical layer of the automotive-specific SerDes (Serializer Deserializer). [Prior Art Document] [Non-patent Document]

[Non-patent document 1] MIPI Alliance Specification for A-PHY, Version 1.1, MIPI Alliance, Inc., August 9, 2021.

[Problem to be solved by the invention] Previously, in a communication system where physical wiring is allocated for each signal, communication control can be performed at each timing. However, in a system where multiple types of data are transmitted between a communication target device on one physical wiring, there is a risk of generating a communication conflict in the same direction.

This disclosure is made in view of this situation and can avoid the same-direction communication conflict in one physical wiring. [Technical means to solve the problem]

The communication method of the first aspect of the present disclosure enables a communication device to interrupt the transmission of the second data by inserting interrupt control data into the first data when inputting the second data while sending the first data using a physical layer that can transmit multiple types of data between the communication target device and the communication target device on one physical wiring.

The communication device of the first aspect of the present disclosure includes: a communication unit, which, when inputting second data while sending first data at a physical layer that can transmit multiple types of data between a communication target device on one physical wiring, interrupts the sending of the second data by inserting interrupt control data into the first data.

The communication device of the second aspect of the present disclosure includes: a communication unit, which, when receiving the first data at a physical layer that can transmit multiple types of data between a communication target device and a communication target device on one physical wiring, receives the second data whose transmission is interrupted, and based on the interruption information indicating that the transmission has been interrupted and stored in the packet header of the second data, preferentially forwards the second data to the upper layer.

In the first aspect of the present disclosure, when the second data is input while the first data is being sent using a physical layer that can transmit a plurality of types of data with a communication target device over one physical wiring, the sending of the second data is interrupted by inserting interrupt control data into the first data.

In the second aspect of the present disclosure, when a physical layer that can transmit multiple types of data between a communication object device and a physical layer that can transmit multiple types of data on a physical wiring receives a second data whose transmission is interrupted, the second data is preferentially forwarded to an upper layer based on the interruption information indicating that the transmission has been interrupted and stored in the packet header of the second data.

Hereinafter, the embodiment of the present disclosure (hereinafter referred to as the embodiment) will be described. The description will be made in the following order.

1. Comparison between previous communication systems and future communication systems 2. Communication systems using the technology disclosed herein 3. Interruption of SYNC packet transmission and delay of transmission timing 4. Transfer of received SYNC packets to upper layers and adjustment of transfer timing 5. Configuration and operation of terminal-source terminals that can respond to data interruption

<1. Comparison between previous communication systems and future communication systems> Previously, in a communication system where physical wiring was allocated for each signal, communication control could be performed at each timing. On the other hand, as a future trend, it is expected that the physical wiring of each signal will be integrated into a high-speed interface including one physical wiring.

FIG. 1 is a diagram showing an example of a communication system that connects a computer (Host) for controlling a vehicle, that is, an ECU (Electronic Control Unit), and a sensor such as an image sensor mounted on a vehicle-mounted camera. FIG. 1A shows a previous communication system, and FIG. 1B shows a communication system assumed in the future.

In each of the previous communication system shown in Figure 1A and the future communication system shown in Figure 1B, the self-sensor transmits image data (Image Data) or GPIO (General Purpose Input/Output) signals to the ECU, and the ECU transmits various specifications of commands such as SYNC/GPIO (synchronization signal) or CAN (Controller Area Network), I2C (Inter-Integrated Circuit) to the sensor.

In the previous communication system, physical wiring was allocated for each data transmitted between the sensor and the SerDes (Serializer Deserializer) on the ECU side. On the other hand, in the future communication system, the physical wiring for each data transmitted between the sensor and the Des (Deserializer) on the ECU side is integrated into one physical wiring according to the A-PHY standard, for example.

When the transmission from the ECU (host) to the sensor is set as an uplink, and the transmission from the sensor to the ECU (host) is set as a downlink, the communication standard dedicated to the vehicle specifies a communication method for simultaneous transmission and reception of the uplink/downlink.

For example, in the MIPI A-PHY specification, FDD (Frequency Division Duplex) can be used to simultaneously implement the uplink from the ECU to the sensor and the downlink from the sensor to the ECU. In addition, in the ASA (Automotive SerDes Alliance) specification, TDD (Time Division Duplex) can be used to avoid signal conflicts in the uplink from the ECU to the sensor and the downlink from the sensor to the ECU.

Fig. 2 is a diagram for explaining the SYNC flow in the conventional communication system shown in Fig. 1A. SYNC is a synchronization signal used in a sensor of a communication target device of a host computer (ECU).

In Figure 2, the ECU sends commands and SYNC to the sensor's PHY uplink via the Des's PHY (the communication unit that performs A-PHY-related processing). In Figure 2, commands are displayed as multiple bytes of data according to CAN or I2C.

As mentioned above, in the previous communication system, since physical wiring is allocated for each data, the command and SYNC are transmitted in parallel on each communication path. Therefore, as shown in the dotted box C1 in Figure 2, even if the transmission timing of the SYNC from the host and the command of I2C overlap, the sensor can receive each data in parallel.

FIG. 3 is a diagram illustrating the SYNC process in the future communication system shown in FIG. 1B.

In Figure 3, similar to Figure 2, the ECU sends commands and SYNCs to the sensor's PHY uplink via the Des's PHY. As shown in Figure 3, the multi-byte commands are packetized, chunked into a specified size, and sent (split) to the sensor side. On the sensor side, the received data is depacketized and forwarded to the upper layer.

As described above, in future communication systems, since the physical wiring for transmitting each data is integrated into one physical wiring according to the A-PHY specification, for example, commands and SYNC are transmitted serially on one communication path. In particular, in the A-PHY specification, the priority of commands and SYNC/GPIO is the same, and the data input first takes precedence. Therefore, in the example of FIG. 3 , SYNC is scheduled and packetized in a manner such that it is sent after the command is sent. Therefore, as shown in the dashed box C2 in FIG. 3 , when the sending timing of the SYNC from the host coincides with the sending timing of the command from I2C, the sensor receives the SYNC after the reception of the command is completed. In addition, the next SYNC is sent at the original timing. As a result, the SYNC cycle cannot be maintained.

In this way, in a system that transmits multiple types of data between communication target devices on one physical wiring, there is a risk of generating a communication conflict in the same direction. In particular, since the SYNC (synchronization signal) sent from the ECU to the sensor is used for frame synchronization in the sensor, its transmission timing needs to be considered.

In contrast, in the technology disclosed herein, when the second data is input while the first data is sent using a physical layer that can transmit multiple types of data on one physical wiring, interrupt control data is inserted into the first data to interrupt the sending of the second data, thereby avoiding the same-direction communication conflict in one physical wiring.

<2. Communication system using the technology disclosed herein> FIG. 4 is a diagram showing an example of the configuration of a communication system using the technology disclosed herein.

The communication system 1 shown in FIG. 4 is composed of a communication device 10 and a communication device 20. The communication device 10 and the communication device 20 exchange data via a communication path 30 composed of a cable or the like. In the communication system 1, data is transmitted between the communication device 10 and the communication device 20 via an A-PHY network. A-PHY is a physical layer of a vehicle-specific SerDes and is a specification specified by the MIPI Alliance. Here, the specification specified by the MIPI Alliance is referred to as the MIPI specification.

The communication device 10 includes a processing unit 11 and a communication unit 12. The processing unit 11 is composed of a chip that performs processing related to PAL (Protocol Adaptation Layer) or a CPU (Central Processing Unit) that controls the operation of each unit of the communication device 10. The communication unit 12 is composed of a chip that performs processing related to data transmission. The communication unit 12 performs processing related to A-PHY (mainly processing of the PHY layer). The processing unit 11 performs processing related to the upper layer of the upper layer of A-PHY.

The communication device 20 includes a processing unit 21 and a communication unit 22. The processing unit 21 is composed of a chip that performs processing related to PAL, or a CPU that controls the operation of each unit of the communication device 20. The communication unit 22 is composed of a chip that performs processing related to data transmission. The communication unit 22 performs processing related to A-PHY. The processing unit 21 performs processing related to the upper layer of the upper layer of A-PHY.

In the communication system 1, one of the communication device 10 and the communication device 20 becomes a source, and the other becomes a sink. The source and the sink are defined in the MIPI specification. In the following, the communication device 10 becomes a sink equivalent to the Des in FIG. 3 , and the communication device 20 becomes a source equivalent to the sensor in FIG. 3 . In addition, the transmission from the source to the sink is called a downlink, and the transmission from the sink to the source is called an uplink. The transmission speed (communication speed) is different in the downlink and the uplink, and the downlink is faster than the uplink.

Here, it is assumed that in the communication system 1, the communication device 10 on the terminal side sends an A-packet to the communication device 20 on the source side by serial communication via the communication path 30. In this case, data in various forms such as GPIO, I2C, and CAN are processed in the processing unit 11. In the processing unit 11, an A-packet is generated from the data in various forms.

The communication unit 12 sends the A-packet generated by the processing unit 11. At this time, the communication unit 12 adds an MC (Message Counter) number to the A-packet sent. For example, the MC number is a value from 0 to 255, and a different number is added to each A-packet. In this example, by setting the initial value to 0, incrementing it for each A-packet, and returning to 0 when the value reaches 255, the MC number can be continuously added. In addition, the communication unit 12 can add a time stamp to the A-packet sent.

FIG. 5 is a diagram showing an example of the structure of an A-packet.

As shown in FIG. 5 , an A-Packet is composed of an A-Packet Header, an A-Packet Payload, and an A-Packet Tail.

The A-packet header includes 8-bit Adaptation Descriptor, 8-bit Service Descriptor, 8-bit Placement Descriptor, 8-bit PHY2, 8-bit Target Address, 8-bit PHY3, 8-bit Payload Length, and 8-bit PHY Header Cyclic Redundancy Check (PHY Header CRC).

A-Packet payload can contain a timestamp field. Timestamp is a field for configuring timestamps.

In addition, when the communication device 20 on the source side sends an A-packet to the communication device 10 on the terminal side, the terminal side performs basically the same processing as the source side, except that the processing on the terminal side is opposite to that on the source side.

<3. Interruption of SYNC packet transmission and delay of transmission timing> Here, the interruption of SYNC packet transmission and delay of transmission timing implemented in the above communication system 1 are explained.

(Interrupted transmission of SYNC packets) Figure 6 is a diagram illustrating the interrupted transmission of SYNC packets implemented in the communication system 1.

In Fig. 6, it is shown that the command and SYNC are transmitted from the terminal side, i.e., the host (ECU), to the source side, i.e., the sensor (communication device 20), via the PHY of Des (communication device 10). Here, it is assumed that data is transmitted and received according to the A-PHY specification.

First, in the process of sending a command (byte data) from the host side, at timing T11, when the processing unit 11 of the communication device 10 inputs SYNC (a synchronization signal for frame synchronization in the sensor), an interrupt flag is generated.

The communication unit 12 of the communication device 10 inserts interrupt control data (INT1, INT2) at the timing T12 after outputting the A-packet of the command being sent according to the interrupt flag. The interrupt control data is data including a control code (Code) indicating interruption of the sending packet.

At the subsequent timing T13, the communication unit 12 of the communication device 10 continues to interrupt the control data and interrupts the sending of the SYNC A-packet. At this time, the above-mentioned time stamp can also be added to the SYNC A-packet.

After stopping sending the A-packet of SYNC, at the timing T14, the communication unit 12 of the communication device 10 continues to send the A-packet of the unsent command.

In the uplink of A-PHY, each request or packet is sent by continuously transmitting CM (Control Mark) and CN (Control Nibbles). In the communication system 1, CM and CN are used as interrupt control data (INT1, INT2), and a format for interrupting the sending of A-packets is newly defined in CN.

FIG. 7 is a diagram showing an example of a newly defined CN (Control Nibbles).

In FIG. 7 , Null, PS (Packet Start), PE (Packet End), RRS (Ret.Req.Start), RE (Req.End), GRS (Gap Req.Start), RTR (Re-Train Req.), CMR (sCMax Req.), INT (Interrupt)/PC (Packet Continue), ACK (Ack Indication) are CNs specified in the current method. In FIG. 7 , PINT (Packet Interrupt) is a CN newly specified in the present disclosure, indicating interruption of packet transmission. The code of PINT can be used for the codes not used in the current method, such as 1110. This allows the use of the novel format of CM and CN as interrupt control data. In addition, CN is set to be 1-byte data consisting of 2 nibbles (4 bits) of CN1 and CN2.

FIG. 8 is a diagram showing a configuration example of a previous CN.

Figure 8A shows an example of CN when a retransmission request is generated when sending data. In this case, INT (Interrupt) is set in CN1 to indicate an interruption, and RRS (Ret.Req.Start) is set in CN2 to indicate a retransmission request. Specifically, INT is first set in CN1 to interrupt the request, and then RRS is set in CN2. The byte data that follows is determined by the content of CN. In this example, the byte data that follows CN consists of the MC sequence number that indicates the packet sequence number of the retransmission request, and CRC (Cyclic Redundancy Check) used for error checking.

In Figure 8B, an example of CN in the case of sending an ACK signal in I2C is shown. In this case, CN1 is set to arbitrary, and ACK (Ack Indication) indicating a positive response is set for CN2. In this example, the byte data following CN is composed of the MC sequence number indicating the packet sequence number of the next ACK to be sent back, and the CRC used for error checking.

In addition, the INT indicating interruption described in FIG8A only specifies interruption of sending byte information. That is, in the previous CN, interruption of sending packets was not specified.

On the other hand, in the present disclosure, a PINT (Packet Interrupt) indicating interruption of packet transmission is set in the CN used for interrupting control data.

FIG. 9 is a diagram showing an example of the configuration of CN used for interrupt control data.

FIG9 shows an example of inserting interrupt control data (CM, CN) after outputting the command from the 1st byte to the Nth byte. In this case, INT (Interrupt) indicating interruption is set in CN1, and PINT (Packet Interrupt) indicating interruption of packet transmission is set in CN2. In this way, the transmission of the SYNC packet is interrupted as the data of the continuation of CN. Furthermore, after the transmission of the SYNC packet is interrupted, the interrupt control data (CM, CN) is inserted to continue the transmission of the command from the unsent (N+1)th byte to the last byte.

In addition, as shown in FIG. 10 , the 1-byte to N-byte command sent before the SYNC packet is interrupted may be discarded, and the command may be resent from the beginning (the first byte) after the SYNC packet is interrupted.

As described above, as CN, a PINT indicating interruption of packet transmission is newly defined. When a SYNC packet is input when sending a command, the CN with the PINT set is inserted to interrupt the transmission of the SYNC packet. This can avoid, for example, a conflict of unidirectional communication in one physical wiring according to the A-PHY specification. Furthermore, the SYNC cycle can be maintained.

(Delay in the sending timing of SYNC packets) In the interrupted sending of SYNC packets as described in reference to Figure 6, since the SYNC packet is inserted after the command being sent is output and the interruption control data is inserted, a constant delay time is generated from the input of the SYNC packet to the interruption of sending. Since this delay time does not occur when there is no need to interrupt the sending of SYNC packets, the time interval between SYNCs (SYNC interval) becomes inconsistent.

Therefore, an example of delaying the transmission timing of the SYNC packet after the transmission is interrupted is described.

Figure 11 is a diagram illustrating the transmission timing delay of the SYNC packet implemented in communication system 1.

FIG. 11 , like FIG. 6 , shows the situation where commands and SYNC are transmitted from the terminal side, i.e., the host (ECU), to the source side, i.e., the sensor's PHY (communication device 20), via the PHY of the Des (communication device 10) uplink.

In FIG. 11 , the delay time from the timing T21 of inputting SYNC to the interruption of sending SYNC packet after inserting interrupt control data is set as t.

In this case, the communication unit 12 of the communication device 10 delays the transmission timing from the timing T22 of inputting the next SYNC packet to the transmission timing by the delay time t even when the transmission does not need to be interrupted. The communication unit 12 of the communication device 10 also delays the transmission timing by the delay time t for subsequent SYNC packets.

In addition, the sending timing of the SYNC packet can be adjusted according to the transmission speed of A-PHY.

As described above, by adjusting the sending timing of all SYNC packets in accordance with the delay time when the sending of SYNC packets is interrupted, the SYNC intervals can be made consistent.

In addition, as shown in FIG12, when a new command is input during the delay period from the timing T22 of inputting the next SYNC to the transmission (after the delay time t), the scheduler performs scheduling in a manner of transmitting the command after the SYNC packet. As mentioned above, in the A-PHY specification, the data input first takes precedence, so here, the command is scheduled and packetized in a manner of transmitting the command after the transmission of the SYNC packet is completed.

<4. Transfer of received SYNC packets to the upper layer and adjustment of transfer timing> Above, the processing on the sending side of sending SYNC packets was explained. Below, as the processing on the receiving side of receiving SYNC packets, the transfer of SYNC packets received in the physical layer to the upper layer and adjustment of transfer timing are explained.

(Forwarding of received SYNC packets to an upper layer) Figure 13 is a diagram illustrating the forwarding of received SYNC packets to an upper layer implemented in communication system 1.

In FIG. 13 , similar to FIG. 11 , in addition to the situation where the command and SYNC are transmitted from the host (ECU) side to the sensor side uplink, the situation where the PHY of the self-sensor forwards the transmitted command and SYNC to the upper layer is also shown.

As described above, on the host (ECU) side, when SYNC is input when sending a command, the sending of the SYNC packet can be interrupted by inserting interrupt control data into the command.

At this time, the MC number of the next command sent by the interrupt is added to the SYNC packet, but the order of the MC number of the SYNC packet and the MC number of the A-packet of the unsent command sent after the interrupt is sometimes reversed. In this case, on the sensor side, the SYNC packet is transferred to the upper layer after the A-packets of all commands sent by the interrupt in the order of the MC number. At this time, the SYNC cycle cannot be maintained in the sensor.

Therefore, as shown in FIG. 13 , at timing T31, when the PHY of the sensor (the communication unit 22 of the communication device 20 ) receives the SYNC packet whose transmission is interrupted, the SYNC packet can be preferentially forwarded to the upper layer.

Specifically, interrupt information indicating interrupt transmission is defined and stored in a SYNC packet of the interrupt transmission. The PHY of the sensor preferentially forwards the SYNC packet to an upper layer based on the interrupt information stored in the SYNC packet.

FIG. 14 is a diagram showing an example of an interrupt indication defined as interrupt information.

In addition to the A-packet structure described in FIG5 , FIG14 also shows the details of the data fields of the A-packet header, including the adaptation descriptor, service descriptor, and placement descriptor. The service descriptor currently includes a data field containing 2 bits of PHY1, 2 bits of priority (Prio), 2 bits of quality of service (QoS), and 1 bit of bad indication (BAD), and the remaining bits are set as reserved (Res).

Therefore, in the present disclosure, the reserved (Res) contained in the service descriptor in the SYNC packet (A-packet header) stores the interrupt indication defined as the interrupt information. In the host side (communication unit 12 of the communication device 10), the interrupt indication can also be stored when the SYNC packet is interrupted.

As described above, on the sensor side, based on the interrupt information contained in the received SYNC packet, the SYNC packet is forwarded to the upper layer first regardless of the order of the MC sequence number. In this way, the SYNC cycle can also be maintained on the sensor side.

(Adjustment of the forwarding timing to the upper layer) In the forwarding of the SYNC packet to the upper layer as described with reference to FIG. 13, the forwarding timing of the SYNC packet to the upper layer can also be adjusted based on the timestamp included in the SYNC packet.

For example, as shown in FIG15 , the PHY of the sensor (the communication unit 22 of the communication device 20) calculates the difference (time interval) between the timestamp included in the SYNC packet received at timing T41 and the timestamp included in the SYNC packet received at timing T42. Furthermore, the PHY of the sensor adjusts the timing of forwarding the SYNC packet received at timing T42 to the upper layer based on the calculated timestamp difference.

Furthermore, when the difference between the timestamps exceeds a specified threshold, at timing T43, the PHY of the sensor may also return a packet (error notification packet) containing error notification information (Error Notification) to the host.

FIG. 16 is a diagram showing an example of the structure of an error notification packet.

The error notification packet shown in FIG16 is basically constructed in the same manner as the A-packet described with reference to FIG5. However, the difference between the error notification packet of FIG16 and the A-packet of FIG5 is that the A-packet payload includes not only a data field of a timestamp but also a data field of a BAD or DROP and an MC number. The BAD or DROP is a data field configured with a BAD/DROP flag, and the BAD/DROP flag indicates that the SYNC packet (error packet) set to a timestamp abnormality is a BAD or DROP packet. The MC number is a data field configured with the MC sequence number of the error packet.

In the host side (communication device 10) that receives the error notification packet, the communication unit 12 notifies the processing unit 11 of the MC number of the SYNC packet (error packet) included in the received error notification packet. In this way, the host side (communication device 10) can detect that there is an abnormality in the SYNC cycle.

Here, the calculation and adjustment of the timestamp difference are explained in detail.

FIG. 17 is a diagram showing a specific example of the calculation of the difference in timestamps.

At the top of Figure 17, 5 frames of SYNC packets are received by the GPIO on the sensor side. In the rectangle representing each SYNC packet, there is a count value indicating the timestamp attached to the SYNC packet. In the figure, when the SYNC packets of frame 0 to frame 4 are displayed from the left, the timestamp (count value) of the SYNC packet of frame 0 is 10, and the timestamp of the SYNC packet of frame 1 is 5010. Similarly, the timestamp of the SYNC packet of frame 2 is 10006, the timestamp of the SYNC packet of frame 3 is 14992, and the timestamp (count value) of the SYNC packet of frame 4 is 19962.

At the bottom of Figure 17, the difference from the time stamp of the SYNC packet of the previous frame is shown as the interval (SYNC width) of the SYNC packets of each frame. That is, the SYNC width of frame 0 is 5010-10=5000, and the SYNC width of frame 1 is 10006-5010=4996. Similarly, the SYNC width of frame 2 is 14992-10006=4986, and the SYNC width of frame 3 is 19962-14992=4970.

Thus, in the example of FIG. 17 , since the SYNC widths are 5000, 4996, 4986, and 4970, there are deviations, and therefore the deviations need to be reduced.

FIG. 18 is a diagram showing a specific example of the calculation of the difference in timestamps.

In the upper part of FIG. 18, as in FIG. 17, the SYNC packets of frame 0 to frame 4 are displayed, and below it, the difference in time stamp with the SYNC packet of the previous frame (1 SYNC interval) is displayed. Furthermore, the difference in 1 SYNC interval is displayed below it. Specifically, the difference in SYNC interval between frame 0 and frame 1 is 4996-5000="-4", the difference in SYNC interval between frame 1 and frame 2 is 4986-4996="-10", and the difference in SYNC interval between frame 2 and frame 3 is 4970-4986="-16".

Here, as thresholds related to the difference in SYNC interval, the first threshold (dead-band threshold) for determining whether the difference in the timestamp from the previous frame needs to be corrected, and the second threshold (error threshold) for determining whether an error notification packet needs to be sent back are defined. When the difference in SYNC interval exceeds the dead-band threshold, the average value of the difference in the SYNC interval from the previous frame is output as the SYNC width of the current frame, and the forwarding timing of the SYNC packet to the upper layer is adjusted. In addition, when the difference in SYNC interval exceeds the error threshold, an error notification packet is sent to the host.

For example, when the deadband threshold is set to ±5 and the error threshold is set to ±12, the SYNC intervals of Frame 0 and Frame 1, 5000 and 4996, are directly output as the SYNC widths of Frame 0 and Frame 1.

On the other hand, the difference "-10" between the SYNC intervals of frame 1 and frame 2 exceeds the deadband threshold. In this case, the SYNC interval of frame 2 needs to be corrected, and the average value Ave (Average) (4996, 4986) = 4991 of the SYNC intervals 4996 and 4986 of frame 1 and frame 2 is replaced with the SYNC width of frame 2. In this way, the deviation of the SYNC width of frame 0 to frame 2 can be reduced, and the SYNC packet is forwarded to the upper layer. At this time, in the internal counter A that counts the SYNC width of each frame, the SYNC width of frame 3 is counted from 14497.

Furthermore, the difference "-16" between the SYNC intervals of frame 2 and frame 3 exceeds the error threshold. In this case, an error notification packet needs to be sent back to the host. At this time, the SYNC interval of frame 3 is not corrected, and the value based on the internal counter A, that is, 19962-14497="4965", is directly output as the SYNC width of frame 3.

As described above, based on the timestamp included in the SYNC packet, the forwarding timing of the SYNC packet to the upper layer is adjusted. In this way, the SYNC cycle can be more accurately maintained on the sensor side.

<5. The structure and operation of the terminal-source that can respond to data interruption> Referring to Figures 19 to 21, the structure and operation of the terminal-source that can respond to data interruption are explained.

(Terminal-source configuration) Figure 19 is a diagram showing an example of a terminal-source configuration that can respond to data interruption.

FIG. 19 shows the structure of a terminal 100 corresponding to the Des on the host (ECU) side and a source 200 corresponding to the sensor.

The terminal 100 is configured to include a data link layer 110 and an A-PHY port 120.

The data link layer 110 implements data transmission with the source end 200 by providing functions or procedures for sending and receiving data via the A-PHY port 120. The data link layer 110 has a port function unit 111. The port function unit 111 converts various input signals into A-packets, and converts A-packets into signals of various specifications and outputs them.

The A-PHY port 120 is equivalent to the communication unit 12 included in the communication device 10 of FIG1 , and performs processing related to A-PHY. The A-PHY port 120 is composed of an RTS (Retransmission) 121 that performs processing related to retransmission, a PCS (Physical Coding Sub-Layer) 122 that performs jamming or encoding of transmitted signals and decoding or descrambling of received signals, and a PMD (Physical Medium Dependent) 123 that is connected to the physical wiring that becomes a communication path.

Among them, RTS121 has a timing adjustment circuit 131, a sending buffer 132, a scheduler 133, a request manager 134 and a CRC addition circuit 135.

The timing adjustment circuit 131 adjusts the output timing of the packet supplied from the data link layer 110. The sending buffer 132 stores the packets that have been sent or the packets scheduled to be sent. The scheduler 133 performs the sending schedule of the packets stored in the sending buffer 132. The request manager 134 controls the sending buffer 132 and the scheduler 133 to manage various requests from the communication object device (source end 200). The CRC adding circuit 135 adds CRC to the sent packet and outputs it to the PCS 122.

The source end 200 is composed of an A-PHY port 210 and a data link layer 220 .

The A-PHY port 210 is equivalent to the communication unit 22 included in the communication device 20 of FIG. 1 , for example, and performs processing related to A-PHY.

The A-PHY port 210 is composed of a PMD 211 connected to a physical wiring serving as a communication path, a PCS 212 that performs decoding or descrambling of received signals and jamming or encoding of transmitted signals, and an RTS 213 that performs processing related to retransmission and the like.

Among them, RTS213 has a CRC check circuit 231 and a receiving buffer 232.

The CRC check circuit 231 performs error detection using the CRC appended to the descrambled packet decoded by the PCS 212.

The receiving buffer 232 stores received packets. The packets stored in the receiving buffer 232 are transferred to the data link layer 220 in the order of MC sequence numbers, for example.

The data link layer 220 implements data transmission with the terminal 100 by providing functions or procedures for sending and receiving data via the A-PHY port 210. The data link layer 220 has a port function unit 221. The port function unit 221 converts input signals of various specifications into A-packets, and converts A-packets into signals of various specifications and outputs them.

In addition, the above mainly describes the structure of realizing the uplink from the terminal 100 to the source 200. In fact, the A-PHY port 120 in the terminal 100 and the A-PHY port 210 in the source 200 have the same functions, and can also realize the downlink from the source 200 to the terminal 100.

(Terminal operation) Referring to the flowchart of FIG. 20 , the sending process of the SYNC packet of the terminal 100 is described. The process of FIG. 20 is executed in the command of various specifications such as CAN, I2C, etc., which can input the SYNC/GPIO signal to the data link layer 110.

In step S101, the data link layer 110 determines whether there is a SYNC input. Step S101 is repeated until it is determined that there is a SYNC input. When it is determined that there is a SYNC input, step S102 is entered. At this time, the port function unit 111 of the data link layer 110 outputs a SYNC packet after converting the input SYNC signal into an A-packet to the A-PHY port 120.

In step S102, the port function unit 111 generates an interrupt flag to notify the request manager 134 of the A-PHY port 120 of the SYNC input.

In step S103, the request manager 134 determines whether there is any contention data each time a SYNC packet is sent based on the packets stored in the sending buffer 132.

When it is determined in step S103 that there is contention data, the process proceeds to step S104, where the scheduler 133 stops the transfer of contention data under the control of the request manager 134 and inserts interrupt control data (CM, CN (INT, PINT)).

In step S105 , the A-PHY port 120 interrupts the sending of the SYNC packet by the interrupt control data inserted by the scheduler 133 .

Furthermore, in step S106, the A-PHY port 120 sends the remaining data that the scheduler 133 stops forwarding.

On the other hand, when it is determined in step S103 that there is no contention data, the A-PHY port 120 directly sends the SYNC packet. At this time, the A-PHY port 120 can delay the sending timing of the SYNC packet by the delay time t as needed.

According to the above processing, when a SYNC packet is input while sending data such as a command, the SYNC packet is interrupted by inserting interrupt control data. This can avoid, for example, a communication conflict in the same direction in one physical wiring according to the A-PHY specification.

(Operation of the source end) Referring to the flowchart of FIG21, the packet reception processing of the source end 200 is explained. Whenever the A-PHY port 210 receives a packet from the terminal 100, the processing of FIG21 is executed.

In step S201, the A-PHY port 210 determines whether there is a break indication defined as break information in the packet header of the received packet. Here, when the break indication is stored in the packet header, the received packet is set as a SYNC packet.

When it is determined in step S201 that there is a disconnection indication, the process proceeds to step S202, and the A-PHY port 210 forwards the SYNC packet to the upper layer (data link layer 220) with the highest priority.

Furthermore, in step S203, the data link layer 220 (port function unit 221) generates and outputs a SYNC signal for frame synchronization based on the transferred SYNC packet.

On the other hand, when it is determined in step S201 that there is no interrupt indication, the process proceeds to step S204, and the A-PHY port 210 forwards the packet to the upper layer (data link layer 220) according to the sequence of the attached MC sequence number.

According to the above processing, based on the interrupt indication contained in the received SYNC packet, the SYNC packet is preferentially forwarded to the upper layer regardless of the order of the MC sequence number. In this way, the SYNC cycle can also be maintained at the source end 200 side.

The above-mentioned terminal and source use the physical wiring according to the A-PHY specification as the communication path to transmit data of various specifications, but the communication path is not limited to the A-PHY specification, and can also be a physical wiring according to other specifications such as the ASA specification. In this case, just set the control code indicating the interruption of the sending packet to the control data equivalent to the specified CN (Control Nibbles).

Furthermore, the instruction for interrupting the SYNC packet is not limited to CAN or I2C, but may also be data of specifications such as I3C (Improved Inter-Integrated Circuits), CSI2 (Camera Serial Interface 2), and SPI (Serial Peripheral Interface).

Furthermore, the data that is interrupted from being sent is not limited to SYNC packets, but may also be data that has been converted to a signal with a higher urgency.

In this specification, a system refers to a collection of multiple components (devices, modules (parts), etc.), regardless of whether all the components are in the same housing. Therefore, multiple devices housed in separate housings and connected via a network, and one device with multiple modules housed in one housing are both systems.

Furthermore, the implementation forms to which the technology disclosed herein is applied are not limited to the above-described implementation forms, and various modifications can be made without departing from the gist of the technology disclosed herein.

Furthermore, the present disclosure may adopt the following configuration. (1) A communication method, which is to enable a communication device, when a second data is input while transmitting the first data using a physical layer that can transmit multiple types of data between a communication target device and a communication target device on a physical wiring, to interrupt the transmission of the second data by inserting interrupt control data into the first data. (2) A communication method as described in (1), wherein the interrupt control data includes a control code indicating the interruption of the transmission packet. (3) A communication method as described in (2), wherein the second data is a synchronization signal used in the communication target device. (4) A communication method as described in (3), wherein after interrupting the transmission of the above-mentioned second data, the above-mentioned first data that has not been transmitted is continued to be transmitted. (5) A communication method as described in (3), wherein the above-mentioned first data transmitted before interrupting the transmission of the above-mentioned second data is discarded, and after interrupting the transmission of the above-mentioned second data, the above-mentioned first data is retransmitted from the beginning. (6) A communication method as described in any one of (3) to (5), wherein based on the time from inputting the above-mentioned second data to interrupting the transmission, the transmission timing of the above-mentioned second data to be transmitted later is delayed. (7) A communication method as described in (6), wherein based on the transmission speed in the above-mentioned physical layer, the above-mentioned transmission timing of the above-mentioned second data is adjusted. (8) A communication method as described in (7), wherein when the first data is input during the delay period of the transmission timing of the second data, scheduling is performed in such a way that the first data is transmitted after the second data. (9) A communication method as described in any one of (3) to (8), wherein interruption information indicating that transmission has been interrupted is stored in the packet header of the second data. (10) A communication method as described in (9), wherein the communication object device is when the second data is received while receiving the first data, based on the interruption information, preferentially forwarding the second data to the upper layer. (11) A communication method as described in (10), wherein the communication target device adjusts the transfer timing of the second data to the upper layer based on the timestamp included in the second data. (12) A communication method as described in (11), wherein the communication target device returns a packet containing error notification information to the communication device when the time interval of the timestamp exceeds a threshold. (13) A communication method as described in any one of (1) to (12), wherein the physical layer is the A-PHY specification of MIPI (Mobile Industry Processor Interface). (14) A communication method as described in (13), wherein the interruption control data is set as the CN in the CM (Control Mark) and CN (Control Nibbles) transmitted continuously. (15) A communication device, comprising: a communication unit, which interrupts the transmission of the second data by inserting the interruption control data into the first data when the second data is input while the first data is transmitted using a physical layer that can transmit multiple types of data between a communication target device on one physical wiring. (16) A communication device comprises: a communication unit which, when receiving second data while receiving first data at a physical layer capable of transmitting a plurality of data between a communication target device and the communication target device on a physical wiring, preferentially forwards the second data to an upper layer based on interruption information indicating that transmission has been interrupted and stored in a packet header of the second data.

1: Communication system 10: Communication device 11: Processing unit 12: Communication unit 20: Communication device 21: Processing unit 22: Communication unit 30: Communication path 100: Terminal 110: Data link layer 111: Port function unit 120: A-PHY port 121: RTS 122: PCS 123: PMD 131: Timing adjustment circuit 132: Transmit buffer 133: Scheduler 134: Request manager 135: CRC attachment circuit 200: Source end 210: A-PHY port 211: PMD 212: PCS 213: RTS 220: Data link layer 221: Port function unit 231: CRC check circuit 232: Receive buffer A: Internal counter C1, C2: Dashed frame INT1, INT2: Interrupt control data S101~S107, S201~S204: Step t: Delay time T11, T12, T13, T14, T21, T22, T31, T41, T42, T43: Timing

FIG. 1 is a diagram showing examples of a previous communication system and a future communication system. FIG. 2 is a diagram illustrating the flow of SYNC in a previous communication system. FIG. 3 is a diagram illustrating the flow of SYNC in a future communication system. FIG. 4 is a diagram showing an example of a communication system to which the technology disclosed herein is applied. FIG. 5 is a diagram showing an example of the composition of an A-packet. FIG. 6 is a diagram illustrating the interruption of the transmission of a SYNC packet. FIG. 7 is a diagram showing an example of CN (Control Nibbles). FIG. 8 is a diagram showing an example of the composition of a previous CN. FIG. 9 is a diagram showing an example of the composition of a CN used for interruption control data. FIG. 10 is a diagram showing an example of the composition of a CN used for interruption control data. FIG. 11 is a diagram illustrating a delay in the transmission timing of a SYNC packet. FIG. 12 is a diagram illustrating a delay in the transmission timing of a SYNC packet. FIG. 13 is a diagram illustrating the forwarding of a received SYNC packet to an upper layer. FIG. 14 is a diagram illustrating an example of an interrupt indication. FIG. 15 is a diagram illustrating the adjustment of the forwarding timing to an upper layer. FIG. 16 is a diagram illustrating an example of the configuration of an error notification packet. FIG. 17 is a diagram illustrating a specific example of the calculation of the difference in timestamps. FIG. 18 is a diagram illustrating a specific example of the adjustment of the difference in timestamps. Figure 19 shows an example of a sink-source configuration that can respond to data interruption. Figure 20 is a flow chart illustrating the sending process of a SYNC packet. Figure 21 is a flow chart illustrating the receiving process of a packet.

T11, T12, T13, T14: Timing

Claims (16)

A communication method is to enable a communication device, when a second data is input while sending the first data using a physical layer capable of transmitting a plurality of data between a communication target device and the communication target device on one physical wiring, to interrupt the sending of the second data by inserting interrupt control data into the first data. A communication method as claimed in claim 1, wherein the interrupt control data includes a control code indicating interruption of packet transmission. A communication method as claimed in claim 2, wherein the second data is a synchronization signal used in the communication object device. A communication method as in claim 3, wherein after interrupting the sending of the above-mentioned second data, the above-mentioned first data which has not been sent is continued to be sent. A communication method as claimed in claim 3, wherein the first data sent before the interruption of sending the second data is discarded, and the first data is resent from the beginning after the interruption of sending the second data. A communication method as claimed in claim 3, wherein based on the time from inputting the second data to interrupting the transmission, the transmission timing of the second data to be transmitted later is delayed. A communication method as claimed in claim 6, wherein based on the transmission speed in the physical layer, the transmission timing of the second data is adjusted. A communication method as claimed in claim 7, wherein when the first data is input during the delay period of the transmission timing of the second data, scheduling is performed in such a way that the first data is transmitted after the second data. A communication method as in claim 3, wherein interruption information indicating that the transmission has been interrupted is stored in the packet header of the second data. A communication method as claimed in claim 9, wherein the communication object device, when receiving the second data while receiving the first data, preferentially forwards the second data to an upper layer based on the interruption information. A communication method as claimed in claim 10, wherein the communication object device adjusts the transfer timing of the second data to the upper layer based on the timestamp contained in the second data. The communication method of claim 11, wherein the communication target device returns a packet containing error notification information to the communication device when the time interval of the timestamp exceeds a threshold. The communication method of claim 1, wherein the physical layer is an A-PHY specification of MIPI (Mobile Industry Processor Interface). A communication method as claimed in claim 13, wherein the interrupt control data is set to the CN in the continuously transmitted CM (Control Mark) and CN (Control Nibbles). A communication device, comprising: A communication unit, which utilizes a physical layer capable of transmitting a plurality of types of data between a communication target device and a physical wiring, and interrupts the transmission of the second data by inserting interrupt control data into the first data when the second data is input while the first data is being transmitted. A communication device, comprising: A communication unit, which, when receiving second data while receiving first data using a physical layer capable of transmitting multiple types of data between a communication target device and a communication target device on one physical wiring, preferentially forwards the second data to an upper layer based on interruption information indicating that transmission has been interrupted and stored in a packet header of the second data.