Data transmission system

Abstract

To suppress a decrease in data transmission efficiency while suppressing manufacturing cost in a transmission system.SOLUTION: Provided is a data transmission system 10 for transmitting data bidirectionally between two electronic apparatuses 21, 22. The data transmission system 10 comprises: first unidirectional transmission lines 110, 300, 210 for performing data transmission in a first direction from one electronic apparatus to the other electronic apparatus; second unidirectional transmission lines 120, 400, 220 for performing data transmission in a second direction opposite the first direction between two electronic apparatuses; bidirectional transmission lines 130, 500, 230 for performing data transmission between two electronic apparatuses in a set direction among the first and the second directions; and transmission direction setting units 152, 252 for setting a data transmission direction in the bidirectional transmission lines.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a data transmission system. [Background technology]

[0002] As a bidirectional data transmission method between electronic devices, the PCIe (Peripheral Component Interconnect-Express) standard is known, which combines multiple unidirectional transmission paths that transmit data in only one direction, each in the opposite direction to each other (Non-Patent Document 1). Also known is a method that includes a bidirectional transmission path that allows data transmission in both directions, and switches the transmission direction of the bidirectional transmission path as needed, as in the method used in the DDR4 (Double Data Rate 4) standard (Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] PCI Express Base Specification Revision 5.0 Version 1.0,22 May 2019 [Non-Patent Document 2] JEDEC STANDARD DDR4 SDRAM JESD79-4B, JUNE 2017 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the data transmission method described in Patent Document 1, the number of unidirectional transmission paths is predetermined, so if the amount of data transmission is biased toward one transmission direction, the transmission path used for data transmission in the other transmission direction is not used, and data transmission efficiency may decrease. In addition, it is not possible to handle cases where the ratio of the amount of data transmission in one transmission direction to the amount of data transmission in the other transmission direction changes from time to time. In the data transmission method described in Patent Document 2, data cannot be transmitted while the transmission direction is being switched, so data transmission efficiency decreases. In addition, since the bidirectional transmission path is made up of two pairs of transmitters and receivers, the manufacturing cost of the data transmission system increases compared to a configuration having only a unidirectional transmission path made up of one pair of transmitters and receivers. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] According to one embodiment of the present disclosure, there is provided a data transmission system (10) for bidirectionally transmitting data between two electronic devices (21, 22). The data transmission system includes a first unidirectional transmission path (110, 300, 210) for transmitting data in a first direction from one of the electronic devices to the other of the electronic devices, a second unidirectional transmission path (120, 400, 220) for transmitting data between the two electronic devices in a second direction opposite to the first direction, a bidirectional transmission path (130, 500, 230) for transmitting data in a set direction between the two electronic devices, either the first direction or the second direction, and a transmission direction setting unit (152, 252) for setting the data transmission direction in the bidirectional transmission path.

[0007] According to this embodiment of the data transmission system, a bidirectional transmission path and a transmission direction setting unit are provided, and the bidirectional transmission path transmits data in the data transmission direction set by the transmission direction setting unit, so that the ratio between the amount of data transmitted in the first direction and the amount of data transmitted in the second direction can be adjusted according to the data transmission direction of the bidirectional transmission path, and a decrease in data transmission efficiency can be suppressed. Also, since the system includes not only a bidirectional transmission path but also a first unidirectional transmission path and a second unidirectional transmission path, an increase in the manufacturing cost of the data transmission system can be suppressed compared to a system in which all transmission paths are configured with bidirectional transmission paths. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram showing a schematic configuration of a data transmission system according to a first embodiment. [Diagram 2] 5 is a flowchart showing the procedure of data transmission processing in the first embodiment. [Diagram 3] FIG. 11 is an explanatory diagram showing an example of a packet transmission order. [Figure 4] FIG. 11 is an explanatory diagram showing a procedure of data transmission processing in the second embodiment. [Diagram 5] FIG. 11 is an explanatory diagram showing a procedure of data transmission processing in the second embodiment. [Figure 6] FIG. 11 is an explanatory diagram showing an example of switching of a data transmission direction in the second embodiment. [Figure 7] FIG. 11 is a block diagram showing a schematic configuration of a data transmission system according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A. First embodiment: A-1. System configuration: The data transmission system 10 of this embodiment is provided between the arithmetic device 21 and the arithmetic device 22, and transmits data bidirectionally between the two arithmetic devices. In the following description, as necessary, the data transmission direction in which data is transmitted from the arithmetic device 21 to the arithmetic device 22 is referred to as the "transmission direction," and the data transmission direction in which data is transmitted from the arithmetic device 22 to the arithmetic device 21 is referred to as the "reception direction." The transmission direction corresponds to the "first direction" in this disclosure. The reception direction corresponds to the "second direction" in this disclosure. Note that the data transmission system 10 may be provided not only between two arithmetic devices, but also between any two electronic devices that exchange data, such as storage devices and communication devices, and transmit data bidirectionally between the two electronic devices.

[0010] As shown in Fig. 1, the data transmission system 10 of the present embodiment includes a first transmission / reception device 100, a second transmission / reception device 200, a data bus 300, a data bus 400, and a data bus 500. The first transmission / reception device 100 and the second transmission / reception device 200 are provided corresponding to the arithmetic device 21 and the arithmetic device 22, respectively. The data bus 300, the data bus 400, and the data bus 500 are provided between the first transmission / reception device 100 and the second transmission / reception device 200, respectively, and connect the first transmission / reception device 100 and the second transmission / reception device 200 to each other.

[0011] The first transmission / reception device 100 includes a transmission unit 110, a reception unit 120, a transmission / reception unit 130, a bus 140, and a control unit 150. The second transmission / reception device 200 includes a reception unit 210, a transmission unit 220, a transmission / reception unit 230, a bus 240, and a control unit 250. Since the first transmission / reception device 100 and the second transmission / reception device 200 have the same configuration, the following description will mainly focus on the first transmission / reception device 100.

[0012] The transmitting unit 110 transmits data to the receiving unit 210 via the data bus 300. The transmitting unit 110, the data bus 300, and the receiving unit 210 form a data transmission path for transmitting data in the transmission direction between the arithmetic device 21 and the arithmetic device 22. This data transmission path corresponds to the "first unidirectional transmission path" in this disclosure. Although not shown in FIG. 1, the data transmission system 10 of this embodiment includes a plurality of first unidirectional transmission paths.

[0013] The receiving unit 120 receives data from the transmitting unit 220 via the data bus 400. The receiving unit 120, the data bus 400, and the transmitting unit 220 form a data transmission path for transmitting data in the receiving direction between the arithmetic device 21 and the arithmetic device 22. This data transmission path corresponds to the "second unidirectional transmission path" in this disclosure. Although not shown in FIG. 1, the data transmission system 10 of this embodiment includes a plurality of second unidirectional transmission paths.

[0014] The transmitting / receiving unit 130 includes a transmitting unit 131 and a receiving unit 132. The transmitting / receiving unit 130 is configured to be usable by switching between the transmitting unit 131 and the receiving unit 132 according to a data transmission direction set by a control unit 150 described later. In the following description, the state of the transmitting / receiving unit 130 when the transmitting unit 131 is used is referred to as a "transmitting state", and the state of the transmitting / receiving unit 130 when the receiving unit 132 is used is referred to as a "receiving state". The transmitting / receiving unit 230 included in the second transmitting / receiving device 200 includes a receiving unit 231 and a transmitting unit 232, similar to the transmitting / receiving unit 130.

[0015] The transmitting / receiving unit 130 and the transmitting / receiving unit 230 are connected to each other via a data bus 500. The data bus 500 is configured to be able to transmit data in the transmitting direction and in the receiving direction according to the above-mentioned data transmission direction. The transmitting / receiving unit 130, the data bus 500, and the transmitting / receiving unit 230 form a data transmission path for bidirectional data transmission between the arithmetic device 21 and the arithmetic device 22. Such a data transmission path corresponds to the "bidirectional transmission path" in this disclosure. Although not shown in FIG. 1, the data transmission system 10 of this embodiment includes a plurality of bidirectional transmission paths.

[0016] The control unit 150 is connected to each of the transmitting unit 110, the receiving unit 120, and the transmitting / receiving unit 130 via the bus 140. The control unit 150 includes a transmission control unit 151, a transmission direction setting unit 152, a transmitting buffer 153, and a receiving buffer 154. The control unit 250 includes a transmission control unit 251, a transmission direction setting unit 252, a receiving buffer 253, and a transmitting buffer 254. Since the control unit 150 and the control unit 250 have the same configuration, the control unit 150 will be described below.

[0017] The transmission control unit 151 controls the data transmission of the data (hereinafter also referred to as "transmission request data") output from the arithmetic device 21 via the above-mentioned data transmission path. Specific processing by the transmission control unit 151 will be described later.

[0018] The transmission direction setting unit 152 sets the data transmission direction of the bidirectional transmission path described above. More specifically, it sets whether the state of the transmitting / receiving unit 130 is the above-mentioned transmitting state or receiving state. In this embodiment, the transmission direction setting unit 152 sets the data transmission direction of the bidirectional transmission path at the start of the data transmission system 10 according to the data transmission direction previously specified by the user. For example, when it is predicted that the amount of data transmitted from the arithmetic device 21 to the arithmetic device 22 will be larger than the amount of data transmitted from the arithmetic device 22 to the arithmetic device 21, the user specifies that the data transmission direction is the transmitting direction. Note that, in this embodiment, the transmission direction setting unit 152 sets the data transmission direction of each bidirectional transmission path so that all the data transmission directions of the multiple bidirectional transmission paths are the same. In this way, the transmission direction setting unit 152 can adjust the ratio between the data transmission amount in the transmitting direction and the data transmission amount in the receiving direction according to the tendency of the data transmission amount in the data transmission system 10 by switching the data transmission direction of the bidirectional transmission path. The first transmitting / receiving device 100 and the second transmitting / receiving device 200 each include an interface (not shown) for communicating with a terminal such as a personal computer that allows a user to specify the data transmission direction.

[0019] The transmission buffer 153 temporarily holds transmission request data from the calculation device 21. The reception buffer 154 temporarily holds data received from the second transmission / reception device 200. In this embodiment, the first transmission / reception device 100 includes one reception buffer 154, but may include two or more reception buffers corresponding to the number of reception units 120.

[0020] A-2. Data transmission processing: 2 when the data transmission system 10 is started. Since the processes executed by the control units 150 and 250 are similar, the following description will mainly focus on the process executed by the control unit 150.

[0021] In step S10, the transmission direction setting unit 152 sets the data transmission direction according to the data transmission direction designated in advance by the user. In the following description, it is assumed that the data transmission direction is designated as the transmission direction by the user, and the transmission direction setting unit 152 sets the transmitting / receiving unit 130 to a transmission state.

[0022] In step S20, the transmission control unit 151 judges whether or not there is transmission request data in the transmission buffer 153. If it is judged that there is no transmission request data (step S20: No), the transmission control unit 151 waits until data is output from the calculation device 21. If it is judged that there is transmission request data (step S20: Yes), in step S30, the transmission control unit 151 divides the transmission request data into packets of a predetermined data amount. In addition, in this embodiment, the transmission control unit 151 assigns a number indicating the transmission order to each divided packet. Each transmitted packet is temporarily held in the reception buffer 253 of the control unit 250, which is the destination, and the control unit 250 rearranges the packets in the original order according to the number assigned to each packet, and transmits them to the calculation device 22.

[0023] In step S40, the transmission control unit 151 determines whether the unidirectional transmission path is available, that is, whether the transmitting unit 110 is performing data transmission. If it is determined that the unidirectional transmission path is available (step S40: Yes), in step S50, the transmission control unit 151 transmits the packet using the unidirectional transmission path.

[0024] On the other hand, if it is determined that the unidirectional transmission path is not available (step S40; No), in step S42, the transmission control unit 151 determines whether or not the bidirectional transmission path is available. "The bidirectional transmission path is available" means that the data transmission direction is set to the transmission direction, and the transmission unit 131 included in the transmission / reception unit 130 is not currently transmitting data. If the data transmission direction is set to the reception direction when the data transmission system 10 is started up, the transmission control unit 151 cannot use the bidirectional transmission path for data transmission in the transmission direction in the operating state of the data transmission system 10. In such a case, the transmission control unit 151 transmits packets using only the unidirectional transmission path, and therefore does not need to perform the determination in step S42.

[0025] If it is determined that the bidirectional transmission path is available (step S42: Yes), in step S52, the transmission control unit 151 transmits the packet using the bidirectional transmission path. On the other hand, if it is determined that the bidirectional transmission path is not available (step S42: No), the transmission control unit 151 executes step S40 again.

[0026] After completing step S50 or step S52, in step S60, the transmission control unit 151 determines whether or not all packets have been transmitted. If all packets have not been transmitted (step S60: No), the transmission control unit 151 executes step S40 again. On the other hand, if all packets have been transmitted (step S60: Yes), the transmission control unit 151 executes step S20 again. The transmission control unit 151 repeatedly executes steps S20 to S60 described above while the data transmission system 10 is in an operating state.

[0027] The data transmission process described above will be described more specifically with reference to the example shown in FIG. 3. In FIG. 3, the horizontal axis indicates the passage of time, and when the transmission request data is divided into eight packets P0 to P7, it is shown whether each packet is transmitted using a unidirectional transmission path or a bidirectional transmission path as time passes from the start of transmission. The size of the rectangle indicating each packet corresponds to the length of time required to transmit each packet. That is, compared to the case of transmission using a unidirectional transmission path, even if the amount of data is the same, it takes longer to transmit each packet using a bidirectional transmission path. This is because, in the example shown in FIG. 3, the data bus width of the bidirectional transmission path is smaller than that of the unidirectional transmission path, and the transmission frequency is slower.

[0028] At time t0 when the transmission starts, the unidirectional transmission path is not yet in use and is available, so the packet P0 is transmitted using the unidirectional transmission path. After that, at time t1 when the transmission of the packet P1 starts, the unidirectional transmission path is used for the transmission of the packet P0 and is not available, so the packet P1 is transmitted using the bidirectional transmission path that is not yet in use and is available. Then, at time t2 when the transmission of the packet P0 ends, the unidirectional transmission path becomes available again, so the packet P2 is transmitted using the unidirectional transmission path. Similarly, for the packets P3 to P7, each packet is transmitted using the transmission path that is available at the time of transmission of each packet. Furthermore, when each packet is transmitted in this manner, the packets are received in the control unit 250, which is the destination, in the order of packets P0, P1, P2, P4, P3, P5, P6, and P7, so that the transmission order and the reception order are different. Each transmitted packet is temporarily held in the reception buffer 253, and the control unit 250 rearranges the packets in the original order according to the number assigned to each packet, and transmits them to the calculation device 22.

[0029] According to the data transmission system 10 of the first embodiment described above, the system includes a bidirectional transmission path and a transmission direction setting unit 152, and the bidirectional transmission path transmits data in the data transmission direction set by the transmission direction setting unit 152, so that the ratio between the amount of data transmitted in the sending direction and the amount of data transmitted in the receiving direction can be adjusted according to the data transmission direction of the bidirectional transmission path, thereby suppressing a decrease in data transmission efficiency. Also, since the system includes not only a bidirectional transmission path but also a first unidirectional transmission path and a second unidirectional transmission path, an increase in the manufacturing cost of the data transmission system 10 can be suppressed compared to a configuration in which all transmission paths are configured as bidirectional transmission paths.

[0030] In addition, since the transmission direction setting unit 152 sets the data transmission direction when the data transmission system 10 is started up, there is no need to execute processing for setting the data transmission direction while the data transmission system 10 is in an operating state, and this makes it possible to prevent the data transmission processing from becoming complicated.

[0031] B. Second embodiment: The data transmission system 10 of the second embodiment differs from the data transmission system 10 of the first embodiment in that, as shown in Fig. 4, steps S54 and S56 are executed after step S50, and in that steps S70, S80 and S90 shown in Fig. 5 are executed in parallel with steps S10 to S60. The system configuration and other steps in the data transmission process of the data transmission system 10 of the second embodiment are the same as those of the data transmission system 10 of the first embodiment, so the same configurations and steps are denoted by the same reference numerals and detailed descriptions thereof are omitted.

[0032] After step S50, in step S54, the transmission control unit 151 judges whether or not the periodic time has elapsed after the data transmission system 10 is started or after the predetermined periodic time has elapsed last time. If it is judged that the periodic time has elapsed (step S54: Yes), in step S56, the transmission control unit 151 transmits the amount of transmission request data held in the transmission buffer 153 to the control unit 250 using the unidirectional transmission path (hereinafter, also referred to as the "first transmission request data amount"). In the control unit 250, the transmission control unit 251 transmits the second transmission request data amount held in the transmission buffer 254 to the control unit 150 at the same timing. As described above, since the transmission request data amount is transmitted after the transmission of the packet using the unidirectional transmission path and after the periodic time has elapsed, it is possible to suppress the interruption of the transmission of the packet in order to transmit the transmission request data amount. Thereafter, the transmission control unit 151 executes the above-mentioned step S60.

[0033] On the other hand, if it is determined that the periodic time has not elapsed (step S54: No), step S56 is not executed and the above-mentioned step S60 is executed.

[0034] 4 and 5, in parallel with the above-mentioned steps S10 to S60, the transmission direction setting unit 152 determines in step S70 whether the periodic time has elapsed after the data transmission system 10 is started or after the above-mentioned periodic time has elapsed previously. If it is determined that the periodic time has not elapsed (step S70: No), the transmission direction setting unit 152 waits until it is determined that the periodic time has elapsed.

[0035] If it is determined that the periodic time has elapsed (step S70: Yes), in step S80, the transmission direction setting unit 152 determines whether the transmission of the first transmission request data amount to the control unit 250 and the reception of the second transmission request data amount from the control unit 250 have already been executed (whether transmission and reception have been completed). If it is determined that transmission and reception have not been completed (step S80: No), the transmission direction setting unit 152 waits until it is determined that transmission and reception have been completed.

[0036] If it is determined that transmission and reception have been completed (step S80: Yes), in step S90, the transmission direction setting unit 152 determines the data transmission direction. In this embodiment, the transmission direction setting unit 152 compares the first transmission request data amount acquired from the transmission buffer 153 with the second transmission request data amount received from the control unit 250, and sets the data transmission direction so that data is transmitted from the arithmetic device that is the source having a larger transmission request data amount to the other arithmetic device.

[0037] More specifically, when the first transmission request data amount is larger than the second transmission request data amount, the transmission direction setting unit 152 sets the data transmission direction to the sending direction so that data is transmitted from the arithmetic device 21, which is the source having a larger transmission request data amount, to the arithmetic device 22. On the other hand, when the second transmission request data amount is larger than the first transmission request data amount, the transmission direction setting unit 152 sets the data transmission direction to the receiving direction so that data is transmitted from the arithmetic device 22, which is the source having a larger transmission request data amount, to the arithmetic device 21.

[0038] Furthermore, when step S90 is executed by the transmission direction setting unit 152, the transmission direction setting unit 252 also sets the data transmission direction so that the state of the transceiver unit 130 and the state of the transceiver unit 230 are paired as a sending state and a receiving state, respectively. The reason why the data transmission direction is set after the determination in step S80 is that when either the transmission of the first transmission request data amount or the reception of the second transmission request data amount is not completed, information for setting the data transmission direction is not available in either the transmission direction setting unit 152 or the transmission direction setting unit 252, and the data transmission direction cannot be set so that the states of the transceiver unit 130 and the transceiver unit 230 are paired with each other.

[0039] After step S90, the transmission direction setting unit 152 executes step S70 again.

[0040] The above-described switching of the data transmission direction will be described more specifically with reference to the example shown in FIG. 6. In FIG. 6, the horizontal axis indicates the passage of time, and the timing when the first transmission request data amount is transmitted on the first unidirectional transmission path, the timing when the second transmission request data amount is received on the second unidirectional transmission path, and the timing when the data transmission direction is switched on the bidirectional transmission path are shown. The open rectangles indicate packets transmitted on each unidirectional transmission path, and the size of the rectangles corresponds to the length of time required to transmit each packet. In the example shown in FIG. 6, the data bus width of the second unidirectional transmission path is smaller than that of the first unidirectional transmission path, and it takes time to transmit each packet in the receiving direction even if the data amount is the same. Also, the hatched rectangles indicate the transmission request data amount transmitted on each unidirectional transmission path.

[0041] After data transmission is started at time Tc0, a periodic time elapses at time Tc1. Thereafter, the transmission direction setting unit 152 sets the data transmission direction at a timing when the first transmission request data amount is transmitted at time T1, delayed from the reception of the second transmission request data amount, and transmission and reception are completed. In the example of Fig. 6, the transmission direction setting unit 152 switches the data transmission direction from the transmission direction to the reception direction, since the second transmission request data amount is larger than the first transmission request data amount.

[0042] Then, at time Tc2, the periodic time elapses again. After that, the second transmission request data amount is received at time T2, which is delayed from the transmission of the first transmission request data amount, and the transmission direction setting unit 152 sets the data transmission direction at the timing when transmission and reception are completed. In the example of Fig. 6, the transmission direction setting unit 152 switches the data transmission direction from the receiving direction to the transmitting direction because the first transmission request data amount is larger than the second transmission request data amount.

[0043] According to the data transmission system 10 of the second embodiment described above, the first transmission request data amount and the second transmission request data amount are acquired and compared with each other, and the data transmission direction is set so that data is transmitted from the source arithmetic device having the larger transmission request data amount to the other arithmetic device. Therefore, even if the ratio between the data transmission amount in the sending direction and the data transmission amount in the receiving direction changes from time to time, the data transmission direction can be appropriately set, and a decrease in data transmission efficiency can be further suppressed.

[0044] Furthermore, since the transmission direction setting unit 152 acquires the first transmission request data amount by using the second unidirectional transmission path, and the transmission direction setting unit 252 acquires the second transmission request data amount by using the first unidirectional transmission path, there is no need to provide an additional configuration for acquiring the transmission request data amount, and an increase in the manufacturing cost of the data transmission system 10 can be suppressed.

[0045] C. Third embodiment: 7, the data transmission system 10A of the third embodiment is different from the data transmission system 10 of the second embodiment in that it further includes data transmission paths 610 and 620. The system configuration and other steps in the data transmission process of the data transmission system 10A of the third embodiment are the same as those of the data transmission system 10 of the second embodiment, so the same configurations and steps are denoted by the same reference numerals and detailed descriptions thereof are omitted.

[0046] As shown in FIG. 7, the data transmission system 10A of the third embodiment further includes data amount transmission paths 610 and 620. The data amount transmission path 610 connects the control unit 150 and the control unit 250 to each other, and in this embodiment, the transmission control unit 151 transmits the first transmission request data amount to the control unit 250 via the data amount transmission path 610 instead of the unidirectional transmission path. The data amount transmission path 620 connects the control unit 150 and the control unit 250 to each other, and in this embodiment, the transmission control unit 251 transmits the second transmission request data amount to the control unit 150 via the data amount transmission path 620 instead of the unidirectional transmission path. This allows the control unit 150 and the control unit 250 to exchange the transmission request data amount at any timing regardless of the usage state of the unidirectional transmission path. Note that the data amount transmission path 610 and the data amount transmission path 620 are used only for transmitting the transmission request data amount, so the data bus width may be smaller than that of the above-mentioned unidirectional transmission path.

[0047] According to the data transmission system 10A of the third embodiment described above, the data amount transmission paths 610 and 620 are further provided, and the transmission direction setting unit 152 and the transmission direction setting unit 252 acquire the transmission request data amount via the data amount transmission paths 610 and 620, respectively, so that the transmission request data amount can be exchanged at any timing regardless of the usage state of the one-way transmission path. Therefore, it is not necessary to determine whether the transmission request data amount can be transmitted in the data transmission process, and the processing can be prevented from becoming complicated. In addition, since the transmission request data amount can be exchanged at any timing regardless of the usage state of the one-way transmission path, the difference in the timing of transmission and reception of the first transmission request data amount and the second transmission request data amount can be suppressed, and the delay in the timing of switching the data transmission direction can be suppressed.

[0048] D. Other embodiments: (D1) In the above embodiment, the data transmission system 10 includes a plurality of first unidirectional transmission paths, a plurality of second unidirectional transmission paths, and a plurality of bidirectional transmission paths, but the present disclosure is not limited to this. The data transmission system 10 may include one of each of the above data transmission paths. The data transmission system 10 of this form also achieves the same effects as the above embodiment.

[0049] (D2) In the above embodiment, the data transmission system 10 includes the transmission direction setting unit 152 and the transmission direction setting unit 252, but the present disclosure is not limited to this. The data transmission system 10 may include only the transmission direction setting unit 152, and the state of the transmission / reception unit 230 in addition to the transmission / reception unit 130 may be set by the transmission direction setting unit 152. For example, the transmission direction setting unit 152 may set the state of the transmission / reception unit 230 by transmitting a control signal to the second transmission / reception device 200, which sets the state of the transmission / reception unit 230, using the first unidirectional transmission path.

[0050] (D3) In the above embodiment, the transmission direction setting unit 152 sets the data transmission direction of each of the multiple bidirectional transmission paths so that all of the data transmission directions of the multiple bidirectional transmission paths are the same, but the present disclosure is not limited to this. The transmission direction setting unit 152 may set the data transmission direction so that the data transmission directions of some of the multiple bidirectional transmission paths are opposite to each other. According to the data transmission system 10 of this form, the ratio between the data transmission amount in the sending direction and the data transmission amount in the receiving direction can be finely adjusted, and a decrease in data transmission efficiency can be further suppressed.

[0051] (D4) In the above embodiment, the transmission control unit 151 divides the transmission request data into packets and transmits them, but the present disclosure is not limited to this. If the transmission frequencies of the unidirectional transmission line and the bidirectional transmission line are the same and the unidirectional transmission line and the bidirectional transmission line can be regarded as one data bus, the transmission control unit 151 may transmit the transmission request data without dividing it into packets. According to the data transmission system 10 of this embodiment, the processes of steps S30 to S60 in the data transmission process are unnecessary, so that the process in the data transmission system 10 can be prevented from becoming complicated.

[0052] (D5) In the second embodiment, the transmission direction setting unit 152 sets the data transmission direction by comparing the first transmission request data amount with the second transmission request data amount in the operating state of the data transmission system 10, but the present disclosure is not limited to this. For example, the transmission direction setting unit 152 may receive a data transmission direction from the calculation device 21 or the calculation device 22 in the operating state of the data transmission system 10A and set the data transmission direction to be the specified data transmission direction. The data transmission system 10A of this form also achieves the same effects as the second embodiment.

[0053] The data transmission system 10 and the method described in the present disclosure may be implemented by a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the data transmission system 10 and the method described in the present disclosure may be implemented by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the data transmission system 10 and the method described in the present disclosure may be implemented by one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. Also, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer.

[0054] The present disclosure is not limited to the above-mentioned embodiment, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features in each embodiment corresponding to the technical features in the form described in the Summary of the Invention column can be appropriately replaced or combined in order to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. Furthermore, if the technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0055] 10, 10A... data transmission system, 21, 22... arithmetic unit, 110... transmitting unit, 120... receiving unit, 130... transmitting / receiving unit, 152... transmission direction setting unit, 210... receiving unit, 220... transmitting unit, 230... transmitting / receiving unit, 252... transmission direction setting unit, 300, 400, 500... data bus

Claims

1. A data transmission system (10) for bidirectionally transmitting data between two electronic devices (21, 22), a first unidirectional transmission path (110, 300, 210) for transmitting data in a first direction from one of the electronic devices to the other of the electronic devices; a second unidirectional transmission path (120, 400, 220) for transmitting data in a second direction opposite to the first direction between the two electronic devices; a bidirectional transmission path (130, 500, 230) for transmitting data between the two electronic devices in a set direction of the first direction and the second direction; a transmission direction setting unit (152, 252) for setting a data transmission direction in the bidirectional transmission path; Equipped with Data transmission system.

2. 2. The data transmission system according to claim 1, the transmission direction setting unit sets the data transmission direction when the data transmission system is started. Data transmission system.

3. 2. The data transmission system according to claim 1, the transmission direction setting unit sets the data transmission direction every time a predetermined period of time elapses in an operating state of the data transmission system. Data transmission system.

4. 4. A data transmission system according to claim 3, the transmission direction setting unit acquires a transmission request data amount having each of the electronic devices as a transmission source, compares the amount with each other, and sets the data transmission direction so that data is transmitted from the electronic device that is a transmission source having a larger transmission request data amount of the two electronic devices to the other electronic device. Data transmission system.

5. 5. A data transmission system according to claim 4, the transmission direction setting unit is provided corresponding to each of the electronic devices, each of the transmission direction setting units acquires the transmission request data amount, the transmission request data amount being sent from the other electronic device as a transmission source, via one of the first unidirectional transmission path and the second unidirectional transmission path; Data transmission system.

6. 5. A data transmission system according to claim 4, The method further includes a data amount transmission path (610, 620) which is a transmission path different from the first unidirectional transmission path, the second unidirectional transmission path, and the bidirectional transmission path and which transmits the transmission request data amount of each of the electronic devices; the transmission direction setting unit acquires the transmission request data amount via the data amount transmission path; Data transmission system.

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