Communication device and communication system

Abstract

To obtain a communication device capable of setting an identifier with a simple method.SOLUTION: A communication device according to an embodiment of the disclosure includes: a signal generation circuit capable of generating a second control signal including a first logical level and a second logical level based on a first control signal including the first logical level and the second logical level; a communication interface connected to a communication bus, and capable of receiving an identifier setting command for instructing setting of an identifier of an own device; and a processing circuit capable of setting an identifier based on the identifier setting command if the first control signal is the first logical level and the identifier has not been set based on the identifier setting command. The signal generation circuit is capable of setting the second control signal at the second logical level if the processing circuit has not set the identifier based on the identifier setting command, and is capable of setting the second control signal at the first logical level after the processing circuit has set the identifier based on the identifier setting command.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a communication device and a communication system that communicates using a communication bus. [Background technology]

[0002] Some communication systems perform communication between multiple communication devices via a communication bus. In such communication systems, communication is often performed using identifiers of the multiple communication devices connected to the communication bus. For example, Patent Document 1 discloses a technology that provides a selection circuit that selects one of multiple slave devices connected to the bus and sets the identifier of the slave device selected by the selection circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-46104 Summary of the Invention [Problem to be solved by the invention]

[0004] In a communication system, it is desirable to set the identifiers of multiple communication devices connected to a communication bus in a simple manner.

[0005] It is desirable to provide a communication device and a communication system that allows identifiers to be set in a simple manner. [Means for solving the problem]

[0006] A communication device according to an embodiment of the present invention includes a signal generation circuit, a communication interface, and a processing circuit. The signal generation circuit is capable of generating a second control signal including a first logic level and a second logic level based on a first control signal including the first logic level and the second logic level. The communication interface is connected to a communication bus and is capable of receiving an identifier setting command for instructing setting of an identifier of its own device. The processing circuit is capable of setting an identifier based on the identifier setting command when the first control signal is at the first logic level and the identifier has not been set yet based on the identifier setting command. The signal generation circuit is capable of setting the second control signal to the second logic level when the processing circuit has not set the identifier yet based on the identifier setting command, and is capable of setting the second control signal to the first logic level after the processing circuit has set the identifier based on the identifier setting command.

[0007] A communication system according to an embodiment of the present invention includes a communication bus and a plurality of communication devices connected to the communication bus. Each of the plurality of communication devices includes a signal generation circuit, a communication interface, and a processing circuit. The signal generation circuit is capable of generating a second control signal including a first logic level and a second logic level based on a first control signal including the first logic level and the second logic level. The communication interface is connected to the communication bus and is capable of receiving an identifier setting command for instructing the setting of its own device identifier. The processing circuit is capable of setting an identifier based on the identifier setting command when the first control signal is at the first logic level and the identifier has not yet been set based on the identifier setting command. In each of the plurality of communication devices, the signal generation circuit can set the second control signal to the second logic level when the processing circuit has not yet set the identifier based on the identifier setting command, and can set the second control signal to the first logic level after the processing circuit has set the identifier based on the identifier setting command. The signal generation circuit of each of one or more communication devices other than a predetermined communication device among the plurality of communication devices can supply the generated second control signal as the first control signal to the signal generation circuits of the communication devices other than that communication device.

Advantages of the Invention

[0008] According to the communication device and the communication system according to an embodiment of the present invention, an identifier can be set by a simple method.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description will be made in the following order. 1. First Embodiment 2. Second Embodiment 3. Third Embodiment

[0011] <1. First Embodiment> [Configuration Example] FIG. 1 shows a configuration example of an apparatus system 1 including a communication system according to an embodiment of the present invention. The apparatus system 1 includes a control device 11, a plurality of devices 12, and a communication bus 13.

[0012] The control device 11 is configured to control the operation of the apparatus system 1. The control device 11 has a communication device 20. The communication device 20 can communicate with a communication device 30 (described later) of a plurality of devices 12 via the communication bus 13.

[0013] Each of the plurality of devices 12 performs a predetermined operation. Each of the plurality of devices 12 can be any device. The plurality of devices 12 may operate in cooperation with each other or may operate independently of each other. Each of the plurality of devices 12 may be, for example, a switching power supply device. Each of the plurality of devices 12 has a communication device 30. The communication device 30 can communicate with the communication device 20 and other communication devices 30 via the communication bus 13.

[0014] The communication bus 13 is configured to transmit data exchanged between the control device 11 and the plurality of devices 12. The communication bus 13 is a serial bus in this example. For example, RS-485 can be used as the communication standard. Note that it is not limited to this, and other communication standards may be used instead. Also, for example, it may be a parallel bus.

[0015] In this device system 1, the communication device 20 of the control device 11, the plurality of communication devices 30 of the plurality of devices 12, and the communication bus 13 constitute the communication system 10.

[0016] FIG. 2 shows a configuration example of the communication device 30. FIG. 3 shows a configuration example of the communication system 10. In FIG. 3, for convenience of explanation, some of the components of the communication device 30 are not shown.

[0017] As shown in FIG. 2, the communication device 30 has connectors 31, 32, signal lines 13P, 13N, signal line 14, resistance element 15, communication interface 33, microcontroller 34, memory circuit 35, signal generation circuit 36, and resistance element 37. The power supply voltage VDD of the communication device 30 is generated, for example, inside the device 12 and supplied to the communication device 30.

[0018] Connectors 31 and 32 are configured to connect the communication device 30 to other devices. Each of the connector 31 and the connector 32 is provided with a plurality of terminals for electrically connecting the communication device 30 to other devices.

[0019] Signal lines 13P and 13N are signal lines that constitute the communication bus 13. One end of the signal line 13P is connected to a terminal provided on the connector 31, and the other end is connected to a terminal provided on the connector 32. Similarly, one end of the signal line 13N is connected to a terminal provided on the connector 31, and the other end is connected to a terminal provided on the connector 32. Each of the signal lines 13P and 13N has a predetermined characteristic impedance. As shown in FIG. 3, the signal lines 13P in the plurality of communication devices 30 are connected so as to constitute one signal line, and the signal lines 13N in the plurality of communication devices 30 are connected so as to constitute one signal line. In this example, communication is performed using differential signals on the communication bus 13.

[0020] One end of the signal line 14 is connected to a terminal provided on the connector 31, and the other end is connected to a terminal provided on the connector 32. The signal line 14 has a predetermined characteristic impedance. One end of the resistor element 15 is connected to the signal line 13N, and the other end is connected to the signal line 14. The resistance value of the resistor element 15 is a resistance value corresponding to the characteristic impedances of the signal lines 13P, 13N, and 14. As shown in FIG. 3, in the communication device 30 that is farthest from the communication device 20 among the plurality of communication devices 30, the terminal on the connector 32 connected to the signal line 13P and the terminal on the connector 32 connected to the signal line 14 are connected to each other. Thereby, the signal line 13P and the signal line 13N are connected to each other via the resistor element 15 of this communication device 30 that is farthest from the communication device 20. With this connection, the resistor element 15 functions as a termination resistor of the communication bus 13. Note that, similarly, it is desirable for the communication device 20 to also have a termination resistor of the communication bus 13. One end of this termination resistor is connected to the signal line 13P, and the other end is connected to the signal line 13N.

[0021] The communication interface 33 is configured to communicate with the communication device 20 and other communication devices 30 via the communication bus 13. The communication interface 33 is connected to the signal lines 13P, 13N.

[0022] The microcontroller 34 is configured to control the operation of the communication device 30. The microcontroller 34 performs processing, for example, by executing a program stored in the memory circuit 35. The microcontroller 34 can operate based on, for example, a command received by the communication interface 33. The microcontroller 34 sets the identifier ID of this communication device 30 based on, for example, the control signal CTL1 supplied to the signal generation circuit 36, the identifier ID of this communication device 30, and the setting command received by the communication interface 33, as will be described later, such as at the time of factory shipment. Specifically, as will be described later, when the control signal CTL1 is at a high level and the identifier ID of this communication device 30 is a predetermined initial value (in this example, "1"), the microcontroller 34 sets the identifier ID in the register based on the setting command received by the communication interface 33. In a plurality of communication devices 30, the identifier IDs are set to be different from each other. Thus, in the communication system 10, a plurality of communication devices 30 can be individually identified, and communication can be performed using this identifier ID.

[0023] The memory circuit 35 is a non-volatile memory device and is configured using, for example, a flash memory. In the memory circuit 35, for example, a program executed by the microcontroller 34 is stored. Also, the identifier ID is stored in the memory circuit 35. After the microcontroller 34 sets the identifier ID in the register, it writes this identifier ID to the memory circuit 35. Then, when the communication device 30 is powered on, the microcontroller 34 reads the identifier ID stored in the memory circuit 35 into the register. Thus, the communication system 10 can perform communication using this identifier ID after power-on.

[0024] The signal generation circuit 36 is configured to generate a control signal CTL2 based on the control signal CTL1 and an instruction from the microcontroller 34. The input terminal of the control signal CTL1 in the signal generation circuit 36 is connected to the terminal provided on the connector 31, and the output terminal of the control signal CTL2 is connected to the terminal provided on the connector 32.

[0025] The resistor element 37 is a pull-up resistor element provided at the input terminal of the control signal CTL1 in the signal generation circuit 36. A power supply voltage VDD is supplied to one end of the resistor element 37, and the other end is connected to the input terminal of the control signal CTL1 in the signal generation circuit 36.

[0026] As shown in FIG. 3, a plurality of communication devices 30 are daisy-chain connected. In FIG. 3, the leftmost communication device 30 is the first-stage communication device 30, and the rightmost communication device 30 is the final-stage communication device 30. Each signal generation circuit 36 of the plurality of communication devices 30 other than the final-stage communication device 30 supplies the generated control signal CTL2 as the control signal CTL1 to the signal generation circuit 36 of the next-stage communication device 30. The input terminal of the control signal CTL1 in the signal generation circuit 36 of the first-stage communication device 30 is not connected to other communication devices 30. Therefore, the input terminal of this control signal CTL1 is set to a high level by the resistor element 37. Also, the output terminal of the control signal CTL2 in the signal generation circuit 36 of the final-stage communication device 30 is not connected to other communication devices 30.

[0027] Here, the signal generation circuit 36 corresponds to a specific example of the "signal generation circuit" in one embodiment of the present disclosure. The communication interface 33 corresponds to a specific example of the "communication interface" in one embodiment of the present disclosure. The communication bus 13 corresponds to a specific example of the "communication bus" in one embodiment of the present disclosure. The microcontroller 34 corresponds to a specific example of the "processing circuit" in one embodiment of the present disclosure. The control signal CTL1 corresponds to a specific example of the "first control signal" in one embodiment of the present disclosure. The control signal CTL2 corresponds to a specific example of the "second control signal" in one embodiment of the present disclosure. The communication device 20 corresponds to a specific example of the "control communication device" in one embodiment of the present disclosure.

[0028] [Operations and Functions] Subsequently, the operations and functions of the communication system 10 of the present embodiment will be described.

[0029] (Overall Operation Overview) First, with reference to FIGS. 2 and 3, the overall operation overview of the communication system 10 will be described. The communication device 20 communicates with a plurality of communication devices 30 via the communication bus 13. In each of the communication devices 30, the communication interface 33 communicates with the communication device 20 and other communication devices 30 via the communication bus 13. The signal generation circuit 36 generates the control signal CTL2 based on the control signal CTL1 supplied from the terminal provided on the connector 31 and the instruction from the microcontroller 34. The microcontroller 34 controls the operation of the communication device 30.

[0030] The microcontroller 34 can set the identifier ID of the communication device 30 based on, for example, the control signal CTL1 supplied to the signal generation circuit 36 at the time of factory shipment, the identifier ID of this communication device 30, and the setting command received by the communication interface 33. Specifically, when the control signal CTL1 is at a high level and the identifier ID of this communication device 30 is a predetermined initial value (in this example, "1"), the microcontroller 34 sets the identifier ID in the register based on the setting command received by the communication interface 33. Then, the microcontroller 34 writes the identifier ID into the storage circuit 35 afterwards.

[0031] (Detailed operation) The setting operation of the identifier IDs of the plurality of communication devices 30 will be described in detail below. In the following description, the communication system 10 has eight communication devices 30 (communication devices 30A to 30H). The communication devices 30A to 30H are daisy-chain connected in this order.

[0032] FIG. 4 shows an example of the setting operation of the identifier ID in the communication system 10. (A) shows the transmission operation of the communication device 20, (B) shows the bus signal of the communication bus 13, (C) shows the waveform of the control signal CTL1 of the communication device 30A, (D) shows the identifier ID of the communication device 30A, (E) shows the waveform of the control signal CTL2 of the communication device 30A, (F) shows the identifier ID of the communication device 30B, and (G) shows the waveform of the control signal CTL2 of the communication device 30B. In FIGS. 4(E) and (G), "x" indicates that it can be either a low level (L level) or a high level (H level). FIGS. 5A to 5D show the operating states of the plurality of communication devices 30.

[0033] First, as shown in FIG. 4, the communication device 20 transmits the initialization command CMD1 via the communication bus 13 during the period from timing t11 to t12 (FIGS. 4(A) and (B)). The initialization command CMD1 is a command for instructing the initialization of the identifier ID. In each of the communication devices 30A to 30H, the communication interface 33 receives this initialization command CMD1.

[0034] Then, at timing t13, each microcontroller 34 of communication devices 30A to 30H sets the identifier ID to a predetermined initial value (in this example, "1") based on this initialization command CMD1 (FIGS. 4(D) and (F)). For example, the microcontroller 34 of communication device 30A sets the identifier ID of communication device 30A to the initial value (FIG. 4(D)), and the microcontroller 34 of communication device 30B sets the identifier ID of communication device 30B to the initial value (FIG. 4(F)). The same applies to communication devices 30C to 30H.

[0035] Then, at timing t14, each signal generation circuit 36 of communication devices 30A to 30H sets the control signal CTL2 to a low level (FIGS. 4(E) and (G)). Specifically, based on setting the identifier ID to the initial value, the microcontroller 34 instructs the signal generation circuit 36 to set the control signal CTL2 to the low level, and the signal generation circuit 36 sets the control signal CTL2 to the low level based on this instruction. For example, the signal generation circuit 36 of communication device 30A sets the control signal CTL2 of communication device 30A to the low level (FIG. 4(E)), and the signal generation circuit 36 of communication device 30B sets the control signal CTL2 of communication device 30B to the low level (FIG. 4(G)). The same applies to communication devices 30C to 30H.

[0036] In this way, in communication system 10, as shown in FIG. 5A, the eight identifier IDs in communication devices 30A to 30H become the initial value (in this example, "1"). Also, the eight control signals CTL2 in communication devices 30A to 30H become low levels. As a result, the control signal CTL1 of communication devices 30B to 30H becomes a low level. The control signal CTL1 of communication device 30A is at a high level.

[0037] Next, as shown in FIG. 4, the communication device 20 transmits the setting command CMD101 via the communication bus 13 during the period from timing t21 to t22 (FIGS. 4(A) and (B)). The setting command CMD101 is a command that instructs to set the identifier ID to "101". At each of the communication devices 30A to 30H, the communication interface 33 receives this setting command CMD101.

[0038] Then, at timing t23, the microcontroller 34 of the communication device 30A sets the identifier ID of the communication device 30A to "101" based on the control signal CTL1 of the communication device 30A (FIG. 4(C)), the identifier ID of the communication device 30A (FIG. 4(D)), and this setting command CMD101. Specifically, the control signal CTL1 of the communication device 30A is at a high level, and the identifier ID of the communication device 30A immediately before this timing t23 is the initial value ("1"). Therefore, the microcontroller 34 of the communication device 30A sets the identifier ID of the communication device 30A to "101" based on the setting command CMD101.

[0039] Then, at timing t24, the signal generation circuit 36 of the communication device 30A sets the control signal CTL2 to a high level (FIG. 4(E)). Specifically, the microcontroller 34 of the communication device 30A instructs the signal generation circuit 36 to set the control signal CTL2 to a high level based on the setting of the identifier ID of the communication device 30A, and the signal generation circuit 36 sets the control signal CTL2 to a high level based on this instruction.

[0040] In this way, in the communication system 10, as shown in FIG. 5B, the identifier ID of the communication device 30A becomes "101" according to the setting command CMD101. Also, the control signal CTL2 of the communication device 30A becomes a high level. As a result, the control signal CTL1 of the communication device 30B, which is the next-stage device of the communication device 30A, becomes a high level. The identifier ID of this communication device 30B is still the initial value ("1").

[0041] Next, as shown in FIG. 4, the communication device 20 transmits the setting command CMD102 via the communication bus 13 during the period from timing t31 to t32 (FIGS. 4(A) and (B)). The setting command CMD102 is a command for instructing to set the identifier ID to "102". At each of the communication devices 30A to 30H, the communication interface 33 receives this setting command CMD102.

[0042] Then, at timing t33, the microcontroller 34 of the communication device 30B sets the identifier ID of the communication device 30B to "102" based on the control signal CTL1 of the communication device 30B, the identifier ID of the communication device 30B, and this setting command CMD102 (FIG. 4(F)). Specifically, since the control signal CTL1 of the communication device 30B is the same signal as the control signal CTL2 of the communication device 30A (FIG. 4(E)), it is at a high level, and the identifier ID of the communication device 30B immediately before this timing t33 is the initial value ("1"). Therefore, the microcontroller 34 of the communication device 30B sets the identifier ID of the communication device 30B to "102" based on the setting command CMD102.

[0043] Then, at timing t34, the signal generation circuit 36 of the communication device 30B sets the control signal CTL2 to a high level (FIG. 4(G)). Specifically, the microcontroller 34 of the communication device 30B instructs the signal generation circuit 36 to set the control signal CTL2 to a high level based on setting the identifier ID of the communication device 30B, and the signal generation circuit 36 sets the control signal CTL2 to a high level based on this instruction.

[0044] In this way, in the communication system 10, as shown in FIG. 5C, the identifier ID of the communication device 30B becomes "102" according to the setting command CMD102. Also, the control signal CTL2 of the communication device 30B becomes a high level. As a result, the control signal CTL1 of the communication device 30C, which is the next-stage device of the communication device 30B, becomes a high level. The identifier ID of this communication device 30C is still the initial value ("1").

[0045] In communication system 10, such operations are repeated. As a result, in communication system 10, as shown in FIG. 5D, the identifiers ID of communication devices 30A to 30H are respectively set to "101" to "108". Then, in each of communication devices 30A to 30H, the microcontroller 34 writes the identifier ID of that communication device 30 into the memory circuit 35.

[0046] As described above, in the communication device 30, based on a first control signal (control signal CTL1) including a first logic level (high level) and a second logic level (low level), a signal generation circuit 36 capable of generating a second control signal (control signal CTL2) including a first logic level (high level) and a second logic level (low level), a communication interface 33 connected to the communication bus 13 and capable of receiving an identifier setting command (e.g., setting command CMD102) for instructing the setting of the identifier ID of the own device, and a processing circuit (microcontroller 34) capable of setting the identifier ID based on the identifier setting command when the first control signal (control signal CTL1) is at the first logic level (high level) and the identifier ID has not yet been set based on the identifier setting command are provided. The signal generation circuit 36 can set the second control signal (control signal CTL2) to the second logic level (low level) when the processing circuit (microcontroller 34) has not yet set the identifier ID based on the identifier setting command, and can set the second control signal (control signal CTL2) to the first logic level (high level) after the processing circuit (microcontroller 34) has set the identifier ID based on the identifier setting command. Thus, for example, as shown in FIGS. 4, 5B, and 5C, when the control signal CTL1 is at a high level and the identifier ID of the communication device 30B is the initial value (in this example, "1"), the communication device 30B can set the identifier ID to "102" based on the setting command CMD102 received by the communication interface 33. At this time, since the identifier ID of the communication device 30A is not the initial value, the identifier ID is not set based on the setting command CMD102. Also, each of the communication devices 30C to 30H does not set the identifier ID based on the setting command CMD102 because the control signal CTL1 is at a low level. Therefore, among the communication devices 30A to 30H, the communication device 30B can selectively set the identifier ID based on the setting command CMD102. Thereby, in the communication device 30, the identifier ID can be set in a simple manner.

[0047] That is, for example, in a communication system including a plurality of communication devices, when a physical switch such as a DIP switch is provided in each of the plurality of communication devices and the identifier ID of the plurality of communication devices is set using this physical switch, it is time-consuming. Further, for example, in a communication system including a plurality of communication devices, when the identifier ID of the plurality of communication devices is sequentially set by performing communication via a communication bus, it is necessary to attach and detach the communication devices so that one communication device is connected to the communication bus, which is time-consuming. Further, for example, when the technique described in Patent Document 1 is used, it is necessary to provide a selection circuit for sequentially selecting a plurality of communication devices connected to the communication bus and wiring between this selection circuit and the plurality of communication devices, and the system configuration may become complicated.

[0048] On the other hand, in the communication device 30, a signal generation circuit 36 is provided, and the signal generation circuits 36 of the plurality of communication devices 30 are connected in a daisy chain. As a result, by performing communication via the communication bus, the identifier ID of the plurality of communication devices 30 can be sequentially set, so that labor can be saved. Further, in the communication device 30, with this configuration, the system configuration can be simplified.

[0049] In the communication device 30, the processing circuit (microcontroller 34) determines whether the identifier ID has been set based on the identifier setting command by checking whether the identifier ID is a predetermined initial value (in this example, "1"). Specifically, when the identifier ID is the initial value ("1"), the microcontroller 34 determines that the identifier ID has not been set yet, and when the identifier ID is not the initial value ("1"), the microcontroller 34 determines that the identifier ID has already been set. Thereby, the microcontroller 34 can simply determine whether the identifier ID has been set based on the identifier setting command. Based on this determination, the signal generation circuit 36 sets the control signal CTL2 to a high level after the microcontroller 34 sets the identifier ID, so that the next-stage communication device 30 can set the identifier ID. As a result, in the communication device 30, the identifier ID can be set in a simple manner.

[0050] [Effect] As described above, in this embodiment, a signal generation circuit capable of generating a second control signal including a first logic level and a second logic level based on a first control signal including the first logic level and the second logic level, a communication interface connected to a communication bus and capable of receiving an identifier setting command for instructing the setting of the identifier of the own device, and when the first control signal is at the first logic level and the identifier has not been set yet based on the identifier setting command, a processing circuit capable of setting the identifier based on the identifier setting command are provided. The signal generation circuit can set the second control signal to the second logic level when the processing circuit has not set the identifier yet based on the identifier setting command, and can set the second control signal to the first logic level after the processing circuit has set the identifier based on the identifier setting command. Thereby, the identifier can be set in a simple manner.

[0051] In this embodiment, the processing circuit determines whether an identifier has been set based on an identifier setting command by checking whether the identifier is a predetermined initial value. Therefore, it is possible to simplify the determination of whether an identifier has been set based on the identifier setting command.

[0052] [Modification Example 1-1] In the above embodiment, as shown in FIG. 3, the communication bus 13 is configured using the signal lines 13P and 13N provided in each of the plurality of communication devices 30, but the present invention is not limited thereto. Instead, as shown in FIGS. 6 and 7, the communication bus 13 may be provided outside the plurality of communication devices 30. The communication device 30 according to this modification example has a connector 39. The communication interface 33 is connected to the communication bus 13 via the connector 39. As shown in FIG. 6, the communication bus 13 has a resistance element RES that functions as a termination resistor.

[0053] [Modification Example 1-2] In the above embodiment, it is determined whether the identifier ID has been set by checking whether the identifier ID is a predetermined initial value (in this example, "0"), but the present invention is not limited thereto. Instead, for example, a setting flag F indicating whether the identifier ID has been set may be used. The following describes this modification example in detail.

[0054] FIG. 8 shows a configuration example of the communication device 30 according to this modification example. In the storage circuit 35 of the communication device 30 according to this modification example, an identifier ID and a setting flag F are stored. In this example, the setting flag F becomes "0" when the identifier ID has not yet been set, and becomes "1" when the identifier ID has already been set. After setting the identifier ID and the setting flag F in the register, the microcontroller 34 writes the identifier ID and the setting flag F to the storage circuit 35. Then, when the communication device 30 is powered on, the microcontroller 34 reads the identifier ID and the setting flag F stored in the storage circuit 35 into the register.

[0055] The microcontroller 34 sets the identifier ID of this communication device 30 based on, for example, the control signal CTL1 supplied to the signal generation circuit 36 at the time of factory shipment, the setting flag F of this communication device 30, and the setting command received by the communication interface 33. Specifically, when the control signal CTL1 is at a high level and the setting flag F of this communication device 30 is "0", the microcontroller 34 sets the identifier ID in the register based on the setting command received by the communication interface 33. Then, the microcontroller 34 sets this setting flag F to "1".

[0056] FIG. 9 shows an example of the operation of setting the identifier ID in the communication system 10 according to this modification. (A) shows the transmission operation of the communication device 20, (B) shows the bus signal of the communication bus 13, (C) shows the waveform of the control signal CTL1 of the communication device 30A, (D) shows the identifier ID of the communication device 30A, (E) shows the setting flag F of the communication device 30A, (F) shows the waveform of the control signal CTL2 of the communication device 30A, (G) shows the identifier ID of the communication device 30B, (H) shows the setting flag F of the communication device 30B, and (I) shows the waveform of the control signal CTL2 of the communication device 30B.

[0057] First, as shown in FIG. 9, the communication device 20 transmits the initialization command CMD1 via the communication bus 13 during the period from timing t11 to t12 (FIGS. 9(A) and (B)). At each of the communication devices 30A to 30H, the communication interface 33 receives this initialization command CMD1. Then, at timing t13, each microcontroller 34 of the communication devices 30A to 30H sets the identifier ID to a predetermined initial value (in this example, "1") based on this initialization command CMD1 (FIGS. 9(D) and (G)).

[0058] Then, at timing t14, each microcontroller 34 of communication devices 30A to 30H sets the setting flag F to "0" (Figs. 9(E), (H)). For example, the microcontroller 34 of communication device 30A sets the setting flag F of communication device 30A to "0" (Fig. 9(E)), and the microcontroller 34 of communication device 30B sets the setting flag F of communication device 30B to "0" (Fig. 9(H)). The same applies to communication devices 30C to 30H.

[0059] Also, at this timing t14, each signal generation circuit 36 of communication devices 30A to 30H sets the control signal CTL2 to a low level (Figs. 9(F), (I)).

[0060] In this way, in communication system 10, as shown in Fig. 5A, the eight identifiers ID in communication devices 30A to 30H become the initial values (in this example, "1"). Also, the eight control signals CTL2 in communication devices 30A to 30H become low levels. As a result, the control signals CTL1 of communication devices 30B to 30H become low levels. The control signal CTL1 of communication device 30A is at a high level.

[0061] Next, as shown in Fig. 9, communication device 20 transmits setting command CMD101 via communication bus 13 during the period from timing t21 to t22 (Figs. 9(A), (B)). In each of communication devices 30A to 30H, communication interface 33 receives this setting command CMD101.

[0062] Then, at timing t23, the microcontroller 34 of communication device 30A sets the identifier ID of communication device 30A to "101" based on the control signal CTL1 of communication device 30A (Fig. 9(C)), the setting flag F of communication device 30A (Fig. 9(E)), and this setting command CMD101 (Fig. 9(D)). Specifically, the control signal CTL1 of communication device 30A is at a high level, and the setting flag F of communication device 30A is "0". Therefore, the microcontroller 34 of communication device 30A sets the identifier ID of communication device 30A to "101" based on setting command CMD101.

[0063] Then, at timing t24, the microcontroller 34 of the communication device 30A sets the setting flag F to "1" (Fig. 9(E)). Specifically, the microcontroller 34 of the communication device 30A sets the setting flag F of the communication device 30A to "1" based on setting the identifier ID of the communication device 30A.

[0064] Also, at this timing t24, the signal generation circuit 36 of the communication device 30A sets the control signal CTL2 to a high level (Fig. 9(F)).

[0065] In this way, in the communication system 10, as shown in Fig. 5B, the identifier ID of the communication device 30A becomes "101" according to the setting command CMD101. Also, the control signal CTL2 of the communication device 30A becomes a high level. As a result, the control signal CTL1 of the communication device 30B, which is the next-stage device of the communication device 30A, becomes a high level. The identifier ID of this communication device 30B is still the initial value ("1").

[0066] Next, as shown in Fig. 9, the communication device 20 transmits the setting command CMD102 via the communication bus 13 during the period from timing t31 to t32 (Fig. 9(A), (B)). In each of the communication devices 30A to 30H, the communication interface 33 receives this setting command CMD102.

[0067] Then, at timing t33, the microcontroller 34 of the communication device 30B sets the identifier ID of the communication device 30B to "102" based on the control signal CTL1 of the communication device 30B, the setting flag F of the communication device 30B, and this setting command CMD102 (Fig. 9(G)). Specifically, since the control signal CTL1 of the communication device 30B is the same signal as the control signal CTL2 of the communication device 30A (Fig. 9(F)), it is at a high level, and the setting flag F of the communication device 30B is "0" (Fig. 9(H)). Therefore, the microcontroller 34 of the communication device 30B sets the identifier ID of the communication device 30B to "102" based on the setting command CMD102.

[0068] Then, at timing t34, the microcontroller 34 of the communication device 30B sets the setting flag F to "1" (FIG. 9(H)). Specifically, the microcontroller 34 of the communication device 30B sets the setting flag F of the communication device 30B to "1" based on setting the identifier ID of the communication device 30A.

[0069] Also, at this timing t34, the signal generation circuit 36 of the communication device 30B sets the control signal CTL2 to a high level (FIG. 9(I)).

[0070] In this way, in the communication system 10, as shown in FIG. 5C, the identifier ID of the communication device 30B becomes "102" corresponding to the setting command CMD102. Also, the control signal CTL2 of the communication device 30B becomes a high level. As a result, the control signal CTL1 of the communication device 30C, which is the next-stage device of the communication device 30B, becomes a high level. The identifier ID of this communication device 30C is still the initial value ("1").

[0071] In the communication system 10, such operations are repeated. As a result, in the communication system 10, as shown in FIG. 5D, the identifier IDs of the communication devices 30A to 30H are set to "101" to "108" respectively. And in each of the communication devices 30A to 30H, the microcontroller 34 writes the identifier ID and the setting flag F of the communication device 30 into the storage circuit 35.

[0072] [Modification Example 1-3] In the above-described embodiment, as shown in FIG. 3, the control signal CTL2 generated by the communication device 30 at the final stage is not supplied to other devices, but the present invention is not limited to this. Instead, as shown in FIG. 10, this control signal CTL2 may be supplied to the communication device 20. As a result, the communication device 20 according to this modified example can grasp that the identifier ID has been set in all the communication devices 30 based on the control signal CTL2 supplied from the communication device 30 at the final stage. Therefore, for example, the communication device 20 transmits setting commands in order from the setting command CMD101 in the same manner as in the case of the above-described embodiment (FIG. 4), and when the control signal CTL2 supplied from the communication device 30 at the final stage changes from a low level to a high level, the transmission of the setting command can be stopped. Thereby, in the communication system 10, for example, even when the communication device 20 does not grasp the number of communication devices 30 in the communication system 10, the identifier ID of all the communication devices 30 can be set.

[0073] [Other Modified Examples] Also, two or more of these modified examples may be combined.

[0074] <2. Second Embodiment> Next, the communication system 40 according to the second embodiment will be described. In the present embodiment, a communication device for setting the identifier ID is determined using a power supply signal. That is, in the above-described first embodiment (FIG. 3), the communication device for setting the identifier ID was determined using a control signal, but in the present embodiment, the communication device for setting the identifier ID is determined using a power supply signal. Note that the same reference numerals are given to substantially the same components as those in the communication system 10 according to the above-described first embodiment, and the description will be omitted as appropriate.

[0075] FIG. 11 shows a configuration example of the communication system 40. The communication system 40 includes a communication device 20, a plurality of communication devices 50, and a communication bus 13.

[0076] FIG. 12 shows a configuration example of the communication device 50. The communication device 50 includes a microcontroller 54 and a switch 56. The microcontroller 54 is configured to control the operation of the communication device 50. Also, the microcontroller 54 can control the operation of the switch 56. One end of the switch 56 is connected to a terminal provided on the connector 31, and the other end is connected to a terminal provided on the connector 32. The switch 56 turns on and off based on a signal supplied from the microcontroller 54. When the switch 56 is in the on state, it outputs the power supply signal PV1 supplied to one end of the switch 56 as the power supply signal PV2. The communication interface 33, the microcontroller 54, and the memory circuit 35 are supplied with the power supply signal PV1.

[0077] As shown in FIG. 11, a plurality of communication devices 50 are daisy-chain connected. That is, for each of the plurality of communication devices 50 other than the last-stage communication device 50 among the plurality of communication devices 50, the switch 56 supplies the power supply signal PV2 to the next-stage communication device 50 as the power supply signal PV1. The power supply voltage VDD is supplied to the first-stage communication device 50 as the power supply signal PV1.

[0078] Here, the switch 56 corresponds to a specific example of the "signal generation circuit" in one embodiment of the present disclosure. The microcontroller 54 corresponds to a specific example of the "processing circuit" in one embodiment of the present disclosure. The power supply signal PV1 corresponds to a specific example of the "first control signal" in one embodiment of the present disclosure. The power supply signal PV2 corresponds to a specific example of the "second control signal" in one embodiment of the present disclosure.

[0079] FIG. 13 shows an example of the operation of setting an identifier ID in the communication system 40. (A) shows the transmission operation of the communication device 20, (B) shows the bus signal of the communication bus 13, (C) shows the waveform of the power supply signal PV1 of the communication device 50A, (D) shows the identifier ID of the communication device 50A, (E) shows the waveform of the power supply signal PV2 of the communication device 50A, (F) shows the identifier ID of the communication device 50B, and (G) shows the waveform of the power supply signal PV2 of the communication device 50B. FIGS. 14A to 14D show the operating states of a plurality of communication devices 50. In FIGS. 14A to 14D, the switch 56 is illustrated using symbols indicating the open / closed state.

[0080] In this example, as shown in FIG. 14A, the identifier IDs of the communication devices 50A to 50H have already been initialized and are "1". The power supply voltage VDD is supplied to the communication device 50A as the power supply signal PV1. The switches 56 of the communication devices 50A to 50H are in the off state. Therefore, the power supply voltage VDD is not supplied to the communication devices 50B to 50H.

[0081] As shown in FIG. 13, the communication device 20 transmits the setting command CMD101 via the communication bus 13 during the periods of timings t111 to t112 (FIGS. 13(A) and (B)). In the communication device 50A, the communication interface 33 receives this setting command CMD101. Since the power supply voltage VDD is not supplied to the communication devices 50B to 50H, the communication devices 50B to 50H do not receive this setting command CMD101.

[0082] At timing t113, the microcontroller 54 of the communication device 50A sets the identifier ID of the communication device 50A to "101" based on the power supply signal PV1 (Fig. 13(C)) of the communication device 50A, the identifier ID of the communication device 50A (Fig. 13(D)), and this setting command CMD101. Specifically, since the power supply voltage VDD is supplied as the power supply signal PV1 to the communication device 50A (Fig. 13(C)), the microcontroller 54 of the communication device 50A is operable, and the identifier ID of the communication device 50A immediately before this timing t113 is the initial value ("1"). Therefore, the microcontroller 54 of the communication device 50A sets the identifier ID of the communication device 50A to "101" based on the setting command CMD101.

[0083] At timing t114, the switch 56 of the communication device 50A changes from the off state to the on state and outputs the power supply voltage VDD as the power supply signal PV2 (Fig. 13(E)). Specifically, the microcontroller 54 of the communication device 50A operates the switch 56 based on setting the identifier ID of the communication device 50A, and the switch 56 changes from the off state to the on state. As a result, the switch 56 outputs the power supply voltage VDD as the power supply signal PV2. As a result, the power supply voltage VDD is supplied as the power supply signal PV1 to the communication device 50B, which is the next-stage device of the communication device 50A, and the communication device 50B starts up.

[0084] At timing t115, the communication device 50B reads the identifier ID from the memory circuit 35, and thus the identifier ID of the communication device 50B is set to "1" (Fig. 13(F)).

[0085] In this way, in the communication system 40, as shown in Fig. 14B, the identifier ID of the communication device 50A becomes "101" according to the setting command CMD101. Also, since the switch 56 of the communication device 50A is in the on state, the power supply voltage VDD is supplied to the communication device 50B, which is the next-stage device of the communication device 50A, and the communication device 50B starts up. The identifier ID of this communication device 50B is still the initial value ("1").

[0086] Next, as shown in FIG. 13, the communication device 20 transmits the setting command CMD102 via the communication bus 13 during the period from timing t121 to t122 (FIGS. 13(A) and (B)). At each of the communication devices 50A and 50B, the communication interface 33 receives this setting command CMD102. Since the power supply voltage VDD is not supplied to the communication devices 50C to 50H, the communication devices 50C to 50H do not receive this setting command CMD102.

[0087] Then, at timing t123, the microcontroller 54 of the communication device 50B sets the identifier ID of the communication device 50B to “102” based on the power signal PV1 of the communication device 50B, the identifier ID of the communication device 50B, and this setting command CMD102 (FIG. 13(F)). Specifically, since the power signal PV2 output by the communication device 50A is supplied as the power signal PV1 to the communication device 50B (FIG. 13(E)), the microcontroller 54 of the communication device 50B is operable, and the identifier ID of the communication device 50B immediately before this timing t123 is the initial value (“1”). Therefore, the microcontroller 54 of the communication device 50B sets the identifier ID of the communication device 50B to “102” based on the setting command CMD102.

[0088] Then, at timing t124, the switch 56 of the communication device 50B changes from the off state to the on state and outputs the power supply voltage VDD as the power signal PV2 (FIG. 13(G)). Specifically, the microcontroller 54 of the communication device 50B operates the switch 56 based on setting the identifier ID of the communication device 50B, and the switch 56 changes from the off state to the on state. As a result, the switch 56 outputs the power supply voltage VDD as the power signal PV2. As a result, the power supply voltage VDD is supplied as the power signal PV1 to the communication device 50C, which is the next-stage device of the communication device 50B, and the communication device 50C starts up.

[0089] In this way, in the communication system 40, as shown in FIG. 14C, the identifier ID of the communication device 50B becomes "102" according to the setting command CMD102. Also, since the switch 56 of the communication device 50B is turned on, the power supply voltage VDD is supplied to the communication device 50C, which is the next-stage device of the communication device 50B.

[0090] In the communication system 40, such an operation is repeated. As a result, in the communication system 40, as shown in FIG. 14D, the identifier IDs of the communication devices 50A to 50H are set to "101" to "108", respectively. And in each of the communication devices 50A to 50H, the microcontroller 54 writes the identifier ID of the communication device 50 into the storage circuit 35.

[0091] In this way, in the communication device 50, the first control signal (power supply signal PV1) and the second control signal (power supply signal PV2) are made to be power supply signals. The processing circuit (microcontroller 54) is made to be operable based on the first control signal (power supply signal PV1). The first logic level is made to be the power supply voltage level, and the second logic level is made to be the ground voltage level. As a result, without using the dedicated control signals CTL1 and CTL2 used in the above first embodiment, a communication device that sets the identifier ID using a power supply signal for transmitting the power supply voltage VDD can be determined. As a result, in the communication device 50, the number of control signals can be reduced, and the identifier ID can be set in a simple method.

[0092] As described above, in this embodiment, the first control signal and the second control signal are made to be power supply signals. The processing circuit is made to be operable based on the first control signal. The first logic level is made to be the power supply voltage level, and the second logic level is made to be the ground voltage level. As a result, the identifier can be set in a simple method. Other effects are the same as those in the case of the above first embodiment.

[0093] [Modification Example 2] The modification according to the first embodiment may be applied to the second embodiment described above.

[0094] <3. Third Embodiment> Next, a communication system 80 according to the third embodiment will be described. In this embodiment, a communication device other than the communication device 20 is configured to be able to transmit a setting command. Note that the same reference numerals are given to substantially the same components as those in the communication system 10 according to the first embodiment, and the description thereof will be omitted as appropriate.

[0095] FIG. 15 shows a configuration example of the communication system 80. The communication system 80 includes a communication device 20, a plurality of communication devices 90, and a communication bus 13.

[0096] FIG. 16 shows a configuration example of the communication device 90. The communication device 90 has a microcontroller 94. The microcontroller 94 is configured to transmit a setting command to be received by the communication device 90, which is the next-stage device of the communication device 90, after setting the identifier ID of the communication device 90.

[0097] FIG. 17 shows an example of the operation of setting the identifier ID in the communication system 80. (A) shows the transmission operation of the communication device 20, (B) shows the bus signal of the communication bus 13, (C) shows the waveform of the control signal CTL1 of the communication device 90A, (D) shows the transmission operation of the communication device 90A, (E) shows the identifier ID of the communication device 90A, (F) shows the waveform of the control signal CTL2 of the communication device 90A, (G) shows the transmission operation of the communication device 90B, (H) shows the identifier ID of the communication device 90B, and (I) shows the waveform of the control signal CTL2 of the communication device 90B.

[0098] First, as shown in FIG. 17, the communication device 20 transmits an initialization command CMD1 via the communication bus 13 during the period from timing t311 to t312 (FIGS. 17(A) and (B)). At each of the communication devices 90A to 90H, the communication interface 33 receives this initialization command CMD1.

[0099] Then, at timing t313, each microcontroller 94 of communication devices 90A to 90H sets the identifier ID to a predetermined initial value (in this example, "1") based on this initialization command CMD1 (FIGS. 17(E) and (H)).

[0100] Then, at timing t314, each signal generation circuit 36 of communication devices 90A to 90H sets the control signal CTL2 to a low level (FIGS. 17(F) and (I)).

[0101] In this way, in communication system 80, similar to the case of communication system 10 according to the first embodiment (FIG. 5A), the eight identifiers ID in communication devices 90A to 90H become the initial value (in this example, "1"). Also, the eight control signals CTL2 in communication devices 90A to 90H become low levels. As a result, the control signal CTL1 of communication devices 90B to 90H becomes low level. The control signal CTL1 of communication device 90A is high level.

[0102] Next, communication device 20 transmits setting command CMD101 via communication bus 13 during the period from timing t321 to t322 (FIGS. 17(A) and (B)). In each of communication devices 90A to 90H, communication interface 33 receives this setting command CMD101.

[0103] Then, at timing t323, the microcontroller 94 of communication device 90A sets the identifier ID of communication device 90A to "101" based on the control signal CTL1 of communication device 90A (FIG. 17(C)), the identifier ID of communication device 90A (FIG. 17(E)), and this setting command CMD101.

[0104] Then, at timing t324, the signal generation circuit 36 of communication device 90A sets the control signal CTL2 to a high level (FIG. 17(F)).

[0105] In this way, in the communication system 80, similar to the case of the communication system 10 according to the first embodiment (Fig. 5B), the identifier ID of the communication device 90A becomes "101" according to the setting command CMD101. Also, the control signal CTL2 of the communication device 90A becomes high level. As a result, the control signal CTL1 of the communication device 90B, which is the next-stage device of the communication device 90A, becomes high level. The identifier ID of this communication device 90B is still the initial value ("1").

[0106] Next, during the period from timing t331 to t332, the communication device 90A transmits the setting command CMD102 via the communication bus 13 (Figs. 17(B), (D)). Specifically, the microcontroller 94 of the communication device 90A generates the setting command CMD102 based on setting the identifier ID, and the communication interface 33 transmits this setting command 102 via the communication bus 13. At each of the communication devices 90B to 90H, the communication interface 33 receives this setting command CMD102.

[0107] Then, at timing t333, the microcontroller 94 of the communication device 90B sets the identifier ID of the communication device 90B to "102" based on the control signal CTL1 of the communication device 90B, the identifier ID of the communication device 90B, and this setting command CMD102 (Fig. 17(H)).

[0108] Then, at timing t334, the signal generation circuit 36 of the communication device 90B sets the control signal CTL2 to high level (Fig. 17(I)).

[0109] In this way, in the communication system 80, similar to the case of the communication system 10 according to the first embodiment (Fig. 5C), the identifier ID of the communication device 90B becomes "102" according to the setting command CMD102. Also, the control signal CTL2 of the communication device 90B becomes high level. As a result, the control signal CTL1 of the communication device 90C, which is the next-stage device of the communication device 90B, becomes high level. The identifier ID of this communication device 90C is still the initial value ("1").

[0110] Next, during the time periods of t341 to t342, the communication device 90B transmits the setting command CMD103 via the communication bus 13 (FIGS. 17(B) and (G)). Specifically, the microcontroller 94 of the communication device 90B generates the setting command CMD103 based on setting the identifier ID. The setting command CMD103 is a command for instructing to set the identifier ID to "103". Then, the communication interface 33 of the communication device 90B transmits this setting command 103 via the communication bus 13. At each of the communication devices 90A, 90C to 90H, the communication interface 33 receives this setting command CMD103.

[0111] Thereafter, although not shown, the microcontroller 94 of the communication device 90C sets the identifier ID of the communication device 90C to "103" based on the control signal CTL1 of the communication device 90C, the identifier ID of the communication device 90C, and this setting command CMD103.

[0112] In the communication system 80, such operations are repeated. As a result, in the communication system 80, similar to the case of the communication system 10 according to the first embodiment (FIG. 5D), the identifier IDs of the communication devices 90A to 90H are respectively set to "101" to "108". And at each of the communication devices 90A to 90H, the microcontroller 94 writes the identifier ID of the communication device 90 to the storage circuit 35.

[0113] In this way, in the communication device 90, the processing circuit (microcontroller 94) is capable of generating an identifier setting command corresponding to a communication device 90 among the plurality of communication devices 90 for which the identifier ID has not yet been set. Then, the communication interface 33 enables the identifier setting command generated by the processing circuit (microcontroller 94) to be transmitted via the communication bus. In this way, in the communication system 80, since the microcontroller 94 can transmit the identifier setting command, the number of times the communication device 20 transmits the identifier setting command to each of the plurality of communication devices 90 can be reduced. As a result, in the communication system 80, the operation of the communication device 20 can be simplified, and for example, the labor for creating a program executed by the communication device 20 can be reduced.

[0114] As described above, in this embodiment, the processing circuit is capable of generating an identifier setting command corresponding to a communication device for which the identifier has not yet been set among the communication devices. Then, the communication interface enables the identifier setting command generated by the processing circuit to be transmitted via the communication bus. Thereby, the labor for creating a program can be reduced. Other effects are the same as those in the case of the first embodiment.

[0115] [Modification Example 3] The modification example according to the first embodiment may be applied to the third embodiment described above. Also, the technology of the second embodiment may be combined with the technology of the third embodiment.

[0116] As described above, the present invention has been described with reference to the embodiments and modification examples. However, the present invention is not limited to these embodiments and the like, and various modifications are possible.

[0117] For example, in the above embodiment, the communication device 30 is configured to have the circuit configuration shown in FIG. 2, for example, but is not limited thereto. For example, in the communication device 30, a resistance element 37 is provided, but is not limited thereto, and this resistance element 37 may be omitted. Further, in the communication device 30, an identifier ID is set when the control signal CTL1 is at a high level, but is not limited thereto, and an identifier ID may be set when the control signal CTL1 is at a low level. Further, in the communication device 30, a signal line 14 is provided, but is not limited thereto, and this signal line 14 may be omitted. The same applies to the communication device 50 (FIG. 12), the communication device 70 (FIG. 16), and the communication device 90 (FIG. 20).

[0118] For example, in the above embodiment, as shown in FIG. 2, the microcontroller 34 and the memory circuit 35 are provided separately, but are not limited thereto. Instead, for example, the microcontroller 34 may include the memory circuit 35. In this case, the circuit portion of the microcontroller 34 excluding the memory circuit 35 corresponds to a specific example of the "processing circuit" in an embodiment of the present disclosure.

[0119] For example, in the above embodiment, the memory circuit 35 is assumed to be a non-volatile memory device, but is not limited thereto, and may be a volatile memory device.

[0120] The effects described in this specification are merely examples, and the effects of the present disclosure are not limited to the effects described in this specification. Therefore, other effects may be obtained with respect to the present disclosure.

[0121] Furthermore, the present disclosure can take the following aspects.

[0122] (1) A signal generation circuit capable of generating a second control signal including the first logic level and the second logic level based on a first control signal including the first logic level and the second logic level, A communication interface connected to a communication bus and capable of receiving an identifier setting command for instructing the setting of an identifier of the own device, and a processing circuit capable of setting the identifier based on the identifier setting command when the first control signal is at the first logic level and the identifier has not yet been set based on the identifier setting command and comprising wherein the signal generation circuit is capable of setting the second control signal to the second logic level when the processing circuit has not yet set the identifier based on the identifier setting command, and is capable of setting the second control signal to the first logic level after the processing circuit has set the identifier based on the identifier setting command a communication device. (2) The processing circuit can determine whether the identifier has been set based on the identifier setting command by checking whether the identifier is a predetermined initial value The communication device according to (1) above. (3) The processing circuit can store flag data indicating whether the identifier has been set based on the identifier setting command The communication device according to (1) above. (4) The first control signal and the second control signal are power supply signals, the processing circuit is operable based on the first control signal, the first logic level is a power supply voltage level, and the second logic level is a ground voltage level The communication device according to any one of (1) to (3) above. (5) The processing circuit can generate an identifier setting command for instructing the setting of an identifier of another device, and the communication interface can transmit the identifier setting command generated by the processing circuit via the communication bus The communication device according to any one of (1) to (4) above. (6) A communication bus and A plurality of communication devices connected to the communication bus, comprising: Each of the plurality of communication devices A signal generation circuit capable of generating a second control signal including the first logic level and the second logic level based on a first control signal including the first logic level and the second logic level; A communication interface connected to the communication bus and capable of receiving an identifier setting command for instructing the setting of the identifier of its own device; A processing circuit capable of setting the identifier based on the identifier setting command when the first control signal is at the first logic level and the identifier has not yet been set based on the identifier setting command; having In each of the plurality of communication devices, The signal generation circuit Is capable of setting the second control signal to the second logic level when the processing circuit has not yet set the identifier based on the identifier setting command; After the processing circuit sets the identifier based on the identifier setting command, the second control signal can be set to the first logic level; The signal generation circuit of each of one or more communication devices other than a predetermined communication device among the plurality of communication devices can supply the generated second control signal as the first control signal to the signal generation circuit of the communication device other than that communication device. A communication system. (7) Further comprising a control communication device connected to the communication bus and capable of sequentially transmitting a plurality of the identifier setting commands corresponding to the plurality of communication devices via the communication bus. The communication system according to (6) above. (8) The control communication device can stop transmitting the identifier setting command based on the second control signal generated by the signal generation circuit of the predetermined communication device. The communication system according to (7) above. (9) In each of the one or more communication devices, the processing circuit can generate the identifier setting command corresponding to the communication device in which the identifier has not yet been set based on the identifier setting command among the plurality of communication devices, the communication interface can transmit the identifier setting command generated by the processing circuit via the communication bus. The communication system according to (6) above.

Explanation of Reference Numerals

[0123] 1... device system, 10, 40, 80... communication system, 11... control device, 12... device, 13... communication bus, 13P, 13N, 14... signal line, 15... resistance element, 20... communication device, 30, 30A to 30H, 50, 50A to 50H, 90, 90A to 90H... communication device, 31, 32, 39... connector, 33... communication interface, 34, 54, 94... microcontroller, 35... storage circuit, 36... signal generation circuit, 37... resistance element, 56... switch... communication device, CMD1... initialization command, CMD101 to CMD103... setting command, CTL1, CTL2... control signal, F... setting flag, PV1, PV2... power supply signal, RES... resistance element, VDD... power supply voltage.

Claims

1. A signal generation circuit capable of generating a second control signal including the first logic level and the second logic level based on a first control signal including the first logic level and the second logic level; A communication interface connected to a communication bus and capable of receiving an identifier setting command for instructing setting of an identifier of the own device; A processing circuit capable of setting the identifier based on the identifier setting command when the first control signal is at the first logic level and the identifier has not been set yet based on the identifier setting command; Comprising; The signal generation circuit: Is capable of setting the second control signal to the second logic level when the processing circuit has not set the identifier yet based on the identifier setting command; Is capable of setting the second control signal to the first logic level after the processing circuit sets the identifier based on the identifier setting command A communication device.

2. The processing circuit can determine whether the identifier has been set based on the identifier setting command by checking whether the identifier is a predetermined initial value. The communication device according to claim 1.

3. The processing circuit can store flag data indicating whether the identifier has been set based on the identifier setting command. The communication device according to claim 1.

4. The first control signal and the second control signal are power supply signals, The processing circuit is operable based on the first control signal, The first logic level is a power supply voltage level, The second logic level is a ground voltage level The communication device according to claim 1.

5. The processing circuit can generate an identifier setting command for instructing setting of an identifier of another device, The communication interface can transmit the identifier setting command generated by the processing circuit via the communication bus. The communication device according to claim 1.

6. A communication bus and A plurality of communication devices connected to the communication bus, Comprising, Each of the plurality of communication devices: A signal generation circuit capable of generating a second control signal including the first logic level and the second logic level based on a first control signal including the first logic level and the second logic level; A communication interface connected to the communication bus and capable of receiving an identifier setting command for instructing setting of an identifier of the own device; a processing circuit capable of setting the identifier based on the identifier setting command when the first control signal is at the first logic level and the identifier has not yet been set based on the identifier setting command, and having in each of the plurality of communication devices, the signal generation circuit is capable of setting the second control signal to the second logic level when the processing circuit has not yet set the identifier based on the identifier setting command, is capable of setting the second control signal to the first logic level after the processing circuit has set the identifier based on the identifier setting command, and the signal generation circuit of each of one or more communication devices other than the predetermined communication device among the plurality of communication devices can supply the generated second control signal as the first control signal to the signal generation circuit of a communication device other than that communication device communication system.

7. The communication system according to claim 6, further comprising a control communication device connected to the communication bus and capable of sequentially transmitting a plurality of the identifier setting commands corresponding to the plurality of communication devices via the communication bus. The communication system according to claim 6.

8. The communication system according to claim 7, wherein the control communication device can stop transmitting the identifier setting command based on the second control signal generated by the signal generation circuit of the predetermined communication device. The communication system according to claim 7.

9. In each of the one or more communication devices, the processing circuit can generate the identifier setting command corresponding to a communication device among the plurality of communication devices for which the identifier has not yet been set based on the identifier setting command, and the communication interface can transmit the identifier setting command generated by the processing circuit via the communication bus. The communication system according to claim 6.

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