Communication semiconductor device

Abstract

A communication semiconductor device according to the present invention includes: a first communication circuit and a second communication circuit; a first switchover function unit that is connected to one end of the first communication circuit and one end of the second communication circuit, and that switches over paths for signals with respect to the first communication circuit and the second communication circuit; a second switchover function unit that is connected to an other end of the first communication circuit and an other end of the second communication circuit, and that switches over paths for signals with respect to the first communication circuit and the second communication circuit, and outputs a switchover instruction, regarding an input destination and an output source, to the first switchover function unit and the second switchover function unit, on the basis of a redundant / non-redundant mode switchover signal, and a state of the first communication circuit and the second communication circuit.

Description

[Technical field]

[0001] The present invention relates to a communication semiconductor device capable of switching between a redundant mode and a non-redundant mode. [Background technology]

[0002] As the introduction of an integrated ECU (Electronic Control Unit) into vehicle architecture is being considered, there is a growing need for communication semiconductor devices such as CAN I / F (Controller Area Network I / F) to have redundant functions from the perspective of functional safety.

[0003] For example, the technology described in Patent Document 1 is known as a technology for realizing a redundant function of a semiconductor device. Patent Document 1 describes that a semiconductor device is provided with multiple functional circuit units, a fault detection control circuit causes each functional circuit unit to perform a self-diagnosis operation, a fault determination circuit determines the presence or absence of a fault, and an output signal switching circuit selects the output of the functional circuit unit that is not faulty according to the determination result stored in a memory circuit. In the semiconductor device described in Patent Document 1, the redundant function is realized by inputting the same signal to two or more functional circuit units. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-340877 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, a configuration in which the same signal is input to two or more communication circuits has the problem that each communication circuit cannot be used for an independent purpose, and for systems that do not require redundant functions, the redundant hardware can increase costs.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to propose a communication semiconductor device that has a redundant function and can configure a non-redundant system when the redundant function is not required. [Means for solving the problem]

[0007] In order to solve the above problems, a communication semiconductor device according to one embodiment of the present invention includes a first communication circuit that performs a predetermined operation in response to a signal input and outputs a signal, a second communication circuit that performs a predetermined operation in response to a signal input and outputs a signal, a first switching function unit connected to one end of the first communication circuit and the second communication circuit and switching an input destination and an output source of a signal for the first communication circuit and the second communication circuit, a second switching function unit connected to the other end of the first communication circuit and the second communication circuit and switching an input destination and an output source of a signal for the first communication circuit and the second communication circuit, a diagnostic circuit provided in each of the first communication circuit and the second communication circuit and diagnosing the first communication circuit and the second communication circuit, and a control circuit connected to the first communication circuit and the second communication circuit, and the first switching function unit and the second switching function unit. The control circuit has a switching function control unit that issues switching instructions for the input destination and output source to the first switching function unit and the second switching function unit based on a redundant / non-redundant mode switching signal indicating the operating mode input from outside and the diagnostic results of each diagnostic circuit. Effect of the Invention

[0008] At least one aspect of the present invention provides a communication semiconductor device that includes a first communication circuit, a second communication circuit, a first switching function unit and a second switching function unit that switch signal paths, and controls the first switching function unit and the second switching function unit based on a redundant / non-redundant mode switching signal and states of the first communication circuit and the second communication circuit. This allows at least one aspect of the present invention to include a redundant function and to configure a non-redundant system when the redundant function is not required. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0009] [Figure 1] 1 is a block diagram showing an example of the configuration of a communication semiconductor device according to a first embodiment of the present invention. [Diagram 2] 1 is a circuit diagram showing a configuration example of a first communication circuit according to a first embodiment of the present invention. [Diagram 3] 1 is a circuit diagram showing a configuration example of a first switching function unit according to a first embodiment of the present invention. [Figure 4] FIG. 4 is a circuit diagram showing a configuration example of a second switching function unit according to the first embodiment of the present invention. [Diagram 5] 1 is a circuit diagram showing an example of the configuration of a control circuit according to a first embodiment of the present invention. [Figure 6] 4 is a diagram showing an example of the configuration of a switching content table in which switching contents of a first switching function unit and a second switching function unit according to the first embodiment of the present invention are described. FIG. [Figure 7] FIG. 11 is a diagram illustrating an example of an abnormality notification by a control circuit. [Figure 8] 5A to 5C are diagrams illustrating an example of the diagnosis results of each diagnosis circuit in a redundant mode and control in a switching function control unit according to the first embodiment of the present invention. [Figure 9] 5 is a flowchart showing an example of control processing of a first switching function unit and a second switching function unit by a switching function control unit of a control circuit in a redundant mode according to the first embodiment of the present invention. [Figure 10] 4 is a diagram showing a communication path when a first communication circuit is used in a redundant mode according to the first embodiment of the present invention; FIG. [Figure 11] 4 is a diagram showing a communication path when a first communication circuit fails in a redundant mode according to the first embodiment of the present invention; FIG. [Figure 12] 1 is a diagram showing an example of an IC configuration for avoiding simultaneous destruction of a first communication circuit and a second communication circuit as a configuration of a communication semiconductor device. [Figure 13] 13A and 13B are diagrams illustrating an example of the diagnosis results of each diagnosis circuit in a non-redundant mode and control in a switching function control unit according to a second embodiment of the present invention. [Figure 14]13 is a flowchart showing an example of control processing of a first switching function unit and a second switching function unit by a switching function control unit of a control circuit in a non-redundant mode according to a second embodiment of the present invention. [Figure 15] FIG. 11 is a diagram showing a communication path when a first communication circuit and a second communication circuit are used in a non-redundant mode according to a second embodiment of the present invention. [Figure 16] FIG. 11 is a diagram illustrating a communication path when a first communication circuit with a higher priority fails in a non-redundant mode according to a second embodiment of the present invention. [Figure 17] FIG. 11 is a diagram showing an example in which a first IC and a second IC are connected to different CAN buses in a system in which a communication semiconductor device according to a third embodiment of the present invention is used as a CAN I / F. [Figure 18] This is an example of a case where a first IC and a second IC are connected to the same CAN bus in a system using the communication semiconductor device according to the third embodiment of the present invention as a CAN I / F. [Figure 19] FIG. 13 is a diagram showing an example of the configuration of a switching content table in which switching contents of a first switching function unit according to the third embodiment of the present invention are described. [Figure 20] 19 is a flowchart showing an example of a control process of a first switching function unit by a switching function control unit of a control circuit in the communication semiconductor device shown in FIG. 18. [Figure 21] FIG. 13 is a block diagram showing an example of the configuration of a communication semiconductor device according to a fourth embodiment of the present invention. [Figure 22] FIG. 13 is a diagram illustrating an example of a cutoff request to a higher-level power supply circuit according to the fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, examples of embodiments of the present invention will be described with reference to the accompanying drawings. In this specification and the accompanying drawings, components having substantially the same functions or configurations are given the same reference numerals and duplicated descriptions are omitted. Note that the drawings may be more schematic than the actual embodiment in order to make the description clearer, but they are merely examples and do not limit the interpretation of the present invention.

[0011] <First embodiment> The configuration and operation of the communications semiconductor device according to the first embodiment of the present invention will be described. First, with reference to Figures 1 to 12, when the operation mode of the communication semiconductor device is set to the redundant mode, communication is carried out in one communication system using a main (main system, working system) communication circuit, and when an abnormality occurs in the main communication circuit, the operation is switched to a sub (secondary system, standby system) communication circuit.

[0012] [Configuration of communication semiconductor device] FIG. 1 is a block diagram showing an example of the configuration of a communication semiconductor device according to a first embodiment of the present invention. The illustrated communication semiconductor device 1 includes a first communication circuit 2, a second communication circuit 3, a first switching function unit 4, a second switching function unit 5, and a control circuit 6. Communication signal lines 11a to 11d of a first communication system are connected between the communication semiconductor device 1 and a communication device (not shown) that can communicate with the communication semiconductor device 1. Communication signal lines 12a to 12d of a second communication system can also be connected between the communication semiconductor device 1 and the communication device, but in this embodiment, since there is only one communication system, the communication signal lines 12a to 12d are not considered. The communication signal lines 12a to 12d of the second communication system will be described in the second embodiment.

[0013] The communication semiconductor device 1 receives a redundant / non-redundant mode switching signal 63 indicating an operation mode from the outside (for example, the microcomputer 7 shown in FIG. 17), performs a predetermined communication process, and outputs an abnormality notification 66 as necessary to notify the outside of the state of the communication semiconductor device 1. Microcomputer is an abbreviation for microcomputer.

[0014] In this embodiment, the redundant mode is specified by the redundant / non-redundant mode switching signal 63. In the redundant mode, the signal input to the first communication circuit 2 and the second communication circuit 3 is the same signal.

[0015] [First communication circuit] FIG. 2 is a circuit diagram showing an example of the configuration of the first communication circuit 2. As shown in FIG. The first communication circuit 2 includes communication signal lines 2a to 2d. Signal 2, the first communication circuit 2 in this embodiment is configured to include a transmitter 24 which is a sending circuit, a receiver 25 which is a receiving circuit, and the first diagnostic circuit 21. The first diagnostic circuit 21 is a self-diagnostic circuit that diagnoses the first communication circuit 2.

[0016] The transmitter 24 receives a signal input from the communication signal line 2a connected between the transmitter 24 and the first switching function unit 4 as a received signal, and generates a positive transmission signal and a negative transmission signal from the received signal. Then, for example, the transmitter 24 outputs the positive transmission signal via the communication signal line 2c and the negative transmission signal via the communication signal line 2d to the second switching function unit 5. The positive transmission signal and the negative transmission signal output by the transmitter 24 are also input to the receiver 25 and the diagnostic receiver 211 of the first diagnostic circuit 21, respectively.

[0017] The receiver 25 receives as reception signals a positive signal and a negative signal input from the communication signal lines 2c and 2d connected between the receiver 25 and the second switching function unit 5, and generates a transmission signal from the difference between the two reception signals. For example, the receiver 25 outputs a high level signal (H signal) when there is a potential difference between the reception signals of the communication signal lines 2c and 2d, and outputs a low level signal (L signal) when there is no potential difference. The receiver 25 then outputs the H signal or L signal as a transmission signal to the first switching function unit 4 via the communication signal line 2b. The transmission signal output by the receiver 25 is also input to the comparators 212 and 213 of the first diagnostic circuit 21.

[0018] The first diagnostic circuit 21 includes a diagnostic receiver 211, a comparator 212, a comparator 123, and an OR circuit 214. The configuration and operation of the diagnostic receiver 211 are similar to those of the receiver 25. That is, the diagnostic receiver 211 receives a positive signal and a negative signal input from the communication signal lines 2c and 2d as received signals, generates an output signal 215 from the difference between the two received signals, and outputs the output signal 215 to the comparator 213. The comparator 212 compares the received signal input from the communication signal line 2a to the transmitter 24 with the transmission signal output by the receiver 25 to the communication signal line 2b. The comparator 213 compares the transmission signal output by the receiver 25 to the communication signal line 2b with the output signal 215 of the diagnostic receiver 211.

[0019] The logical sum circuit 214 aggregates the respective comparison results of the comparator 212 and the comparator 213. The logical sum circuit 214 calculates the logical sum of the input values ​​(comparison results) from the comparator 212 and the comparator 213, and outputs the calculation result to the switching function control unit 62 of the control circuit 6 as the diagnosis result 23 of the first diagnosis circuit 21. Regarding the comparison result of the comparator 212, if the two input values ​​to the comparator 212 match, it is determined to be OK (for example, if the difference is less than a predetermined value, an L signal is output), and if they do not match, it is determined to be NG (for example, if the difference is equal to or greater than a predetermined value, an H signal is output). The same is true for the comparator 213.

[0020] [Second communication circuit] The configuration of the second communication circuit 3 is the same as that of the first communication circuit 2. For example, the second communication circuit 3 has a second diagnostic circuit 31 having the same configuration as the first diagnostic circuit 21, and communication signal lines 3a to 3d Signal , and a diagnostic result 33 of the second diagnostic circuit 31. The second diagnostic circuit 31 is a self-diagnostic circuit that diagnoses the second communication circuit 3.

[0021] In this manner, the first communication circuit 2 and the second communication circuit 3 each have a transmitter 24 and a receiver 25. Then, the respective diagnostic circuits (first diagnostic circuit 21, second diagnostic circuit 31) of the first communication circuit 2 and the second communication circuit 3 compare information input to the transmitter 24 with information output from the receiver 25 to diagnose the first communication circuit 2 and the second communication circuit 3, respectively.

[0022] As described above, the first communication circuit 2 and the second communication circuit 3 are equipped with self-diagnosis functions (first diagnostic circuit 21, second diagnostic circuit 31), so that when the main communication circuit fails, it is possible to switch to the sub communication circuit, and it is possible to detect the failure of the sub communication circuit before switching.

[0023] [First switching function part] FIG. 3 is a circuit diagram showing an example of the configuration of the first switching function unit 4. As shown in FIG. The first switching function unit 4 inputs and outputs signals of the communication signal lines 11a and 11b of the first communication system, the communication signal lines 2a and 2b connected to the first communication circuit 2, and the communication signal lines 3a and 3b connected to the second communication circuit 3. The first switching function unit 4 in this embodiment is configured to include switches S1 to S3, as shown in FIG. 3, for example. The switch S1 switches the mover to a stator S1a (first communication system side) or a stator S1b (second communication system side) by a first switching function control signal 64 (FIG. 1) of the control circuit 6. The same is true for the switches S2 and S3. That is, the switch S2 includes a mover, a stator S2a (first communication system side), and a stator S2b (second communication system side), and the switch S3 includes a mover, a stator S3a (first communication system side), and a stator S3b (second communication system side).

[0024] [Second switching function part] FIG. 4 is a circuit diagram showing an example of the configuration of the second switching function unit 5. As shown in FIG. The second switching function unit 5 inputs and outputs signals of the communication signal lines 11c and 11d of the first communication system, the communication signal lines 2c and 2d connected to the first communication circuit 2, and the communication signal lines 3c and 3d connected to the second communication circuit 3. The second switching function unit 5 in this embodiment is configured to include switches S4 to S6, as shown in FIG. 4, for example. The switch S6 switches the mover to a stator S6a (first communication system side) or a stator S6b (second communication system side) by a second switching function control signal 65 (FIG. 1) from the control circuit 6. The same is true for the switches S4 and S5. That is, the switch S4 includes a mover, a stator S4a (first communication system side), and a stator S4b (second communication system side), and the switch S5 includes a mover, a stator S5a (first communication system side), and a stator S5b (second communication system side).

[0025] [Control circuit] The control circuit 6 receives the signals of the communication signal lines 2a and 2b of the first communication circuit 2, the signals of the communication signal lines 3a and 3b of the second communication circuit 3, the diagnosis result 23 of the first diagnostic circuit 21, the diagnosis result 33 of the second diagnostic circuit 31, and a redundant / non-redundant mode switching signal 63. The control circuit 6 also outputs a first switching function control signal 64 to the first switching function unit 4, a second switching function control signal 65 to the second switching function unit 5, and an abnormality notification 66 for notifying the outside (for example, the microcomputer 7 in FIG. 5) of the state of the communication semiconductor device 1.

[0026] As an example, the control circuit 6 in this embodiment is configured to include a mutual diagnosis circuit 61 and a switching function control unit 62 as shown in Fig. 5, and performs an abnormality notification 66 as shown in Fig. 7 described later. For example, the switching function control unit 62 can be configured by combining multiple logic circuits made of semiconductor elements. Also, all or part of the configuration and functions of the control circuit 6 may be configured by a microcomputer, similar to the microcomputer 7.

[0027] FIG. 5 is a circuit diagram showing an example of the configuration of the control circuit 6. As shown in FIG. The mutual diagnosis circuit 61 includes a comparator 611 , a comparator 612 , and a logical OR circuit 613 .

[0028] The comparator 611 compares the signal input from the communication signal line 2a of the first communication circuit 2 with the signal input from the communication signal line 3b of the second communication circuit 3. The comparator 612 compares the signal input from the communication signal line 2b of the first communication circuit 2 with the signal input from the communication signal line 3a of the second communication circuit 3.

[0029] The logical sum circuit 613 aggregates the respective comparison results of the comparator 611 and the comparator 612. The logical sum circuit 613 calculates the logical sum of the input values ​​(comparison results) from the comparator 611 and the comparator 612, and outputs the calculation result to the switching function control unit 62 as the diagnosis result 616 of the mutual diagnosis circuit 61. Regarding the comparison result of the comparator 611, if the two input values ​​to the comparator 611 match, it is determined to be OK (for example, if the difference is less than a predetermined value, an L signal is output), and if they do not match, it is determined to be NG (for example, if the difference is equal to or greater than a predetermined value, an H signal is output). The same is true for the comparator 612.

[0030] Thus, the control circuit 6 includes a mutual diagnosis circuit 61 configured to compare the first communication circuit 2 and the second communication circuit 3 with each other based on the input information and output information of the first communication circuit 2 and the second communication circuit 3 when the operating mode (redundant / non-redundant mode switching signal 63) is the redundant mode, and to output the comparison result (diagnosis result 616) to the switching function control unit 62.

[0031] More specifically, the mutual diagnostic circuit 61 is configured to mutually diagnose the first communication circuit 2 and the second communication circuit 3 by comparing information input to the transmitter 24 of the first communication circuit 2 with information output from the receiver 25 of the second communication circuit 3, and by comparing information input to the transmitter 24 of the second communication circuit 3 with information output from the receiver 25 of the first communication circuit 2.

[0032] The switching function control unit 62 receives as input the diagnosis result 23 of the first diagnostic circuit 21 provided in the first communication circuit 2, the diagnosis result 33 of the second diagnostic circuit 31 provided in the second communication circuit 3, the diagnosis result 616 of the mutual diagnostic circuit 61, and a redundant / non-redundant mode switching signal 63. The switching function control unit 62 issues an input destination and output source switching instruction to the first switching function unit 4 and the second switching function unit 5 based on the redundant / non-redundant mode switching signal 63 and the diagnosis results 23, 33, 616 of the respective diagnostic circuits. As shown in FIG. 5, the switching function control unit 62 outputs a first switching function control signal 64 as an input destination and output source switching instruction to the first switching function unit 4, and a second switching function control signal 65 as an input destination and output source switching instruction to the second switching function unit 5.

[0033] In this way, the switching function control unit 62 switches the signal input paths and output paths in the first switching function unit 4 and the second switching function unit 5 based on the diagnostic result 161 of the mutual diagnostic circuit 61 and the diagnostic results 23, 33 of each diagnostic circuit provided in the first communication circuit 2 and the second communication circuit 3.

[0034] In addition, the switching function control unit 62 outputs an abnormality notification 66 indicating the state of the communication semiconductor device 1, i.e., the state of the first communication circuit 2, the second communication circuit 3, and each diagnostic circuit, based on the diagnostic results 23, 33, and 616 of each diagnostic circuit.

[0035] The switching function control unit 62 also includes a memory 62m that stores the priorities of the first communication circuit 2 and the second communication circuit 3. The priorities will be described in the second embodiment. According to the diagnostic results 23, 33, 616 of the respective diagnostic circuits, the switches S1 to S6 of the first switching function unit 4 and the second switching function unit 5 are controlled as shown in FIG. 6, for example. Details will be described later with reference to the flow chart shown in FIG. 9. Note that for the switch settings and abnormality notification 66 shown in FIG. 9, refer to FIG. 6 and FIG. 7.

[0036] FIG. 6 is a diagram showing an example of the configuration of a switching content table T1 in which switching contents of the first switching function unit 4 and the second switching function unit 5 are recorded. The switching content table T1 has the following items: "Type of switching function unit," "Type of switch," and "Switch setting (connection switching)."

[0037] When the switch setting of the first switching function control signal 64 is "No.1", in the first switching function unit 4, the switch S1 is switched to the stator S1a, the switch S2 is switched to the stator S2a, and the switch S3 is switched to the stator S3a. When the switch setting of the first switching function control signal 64 is "No.2", in the first switching function unit 4, the switch S1 is switched to the stator S1b, the switch S2 is switched to the stator S2a, and the switch S3 is switched to the stator S3a. When the switch setting of the first switching function control signal 64 is "No.3", in the first switching function unit 4, the switch S1 is switched to the stator S1a, the switch S2 is switched to the stator S2b, and the switch S3 is switched to the stator S3b.

[0038] When the switch setting of the second switching function control signal 65 is "No.1", in the second switching function unit 5, the switch S4 is switched to the stator S4a, the switch S5 is switched to the stator S5a, and the switch S6 is switched to the stator S6a. When the switch setting of the second switching function control signal 65 is "No.2", in the second switching function unit 5, the switch S4 is switched to the stator S4a, the switch S5 is switched to the stator S5a, and the switch S6 is switched to the stator S6b. When the switch setting of the second switching function control signal 65 is "No.3", in the second switching function unit 5, the switch S4 is switched to the stator S4b, the switch S5 is switched to the stator S5b, and the switch S6 is switched to the stator S6a.

[0039] FIG. 7 is a diagram showing an example of the abnormality notification 66 by the control circuit 6. As shown in FIG. The switching function control unit 62 of the control circuit 6 outputs one of 2'b00, 2'b01, 2'b10, and 2'b11 as the abnormality notification 66 depending on the state of the communication semiconductor device 1. In this embodiment, the abnormality notification 66 is a 2-bit signal, and the meaning of each abnormality notification is as follows: In this specification, a failure refers to a state in which the communication circuit cannot operate normally. 2'b00: Normal 2'b01: Failure of first communication circuit 2 2'b10: Failure of second communication circuit 3 2'b11: Communication stopped (in non-redundant mode, communication on both communication circuits is stopped)

[0040] [Diagnostic results of each diagnostic circuit and control in the switching function control section] FIG. 8 is a diagram showing an example of the diagnostic results of each diagnostic circuit in the redundant mode and the control in the switching function control unit 62. In FIG. The illustrated table 71 has the following items: "No.", "Diagnosis result of mutual diagnosis circuit", "Diagnosis result of first diagnosis circuit", "Diagnosis result of second diagnosis circuit", and "Control in switching function control unit".

[0041] "No." is a number representing the position of the record in Table 71. "Diagnosis result of mutual diagnosis circuit" indicates the diagnosis result 616 of the mutual diagnosis circuit 61 as OK (good) or NG (bad). "Diagnosis result of first diagnostic circuit" indicates the diagnosis result 23 of the first diagnostic circuit 21 as OK (good) or NG (bad). "Diagnosis result of second diagnostic circuit" indicates the diagnosis result 33 of the second diagnostic circuit 31 as OK (good) or NG (bad). "Control in the switching function control unit" indicates the state of the communication semiconductor device 1 and the contents of control in the switching function control unit 62. Note that in Fig. 8, the contents of control in the switching function control unit 62 are based on the premise that communication is performed in the redundant mode with the first communication circuit 2 as the main communication circuit.

[0042] As shown in record No. 1, when the diagnostic result 616 of the mutual diagnostic circuit 61 is "OK", the diagnostic result 23 of the first diagnostic circuit 21 is "OK", and the diagnostic result 33 of the second diagnostic circuit 31 is "OK", it can be determined that the first communication circuit 2 and the second communication circuit 3, and the first diagnostic circuit 21 and the second diagnostic circuit 31 are all normal. Therefore, the switching function control unit 62 controls the first switching function unit 4 and the second switching function unit 5 so as to continue communication via the first communication circuit 2.

[0043] As shown in record No. 2, when the diagnostic result 616 of the mutual diagnostic circuit 61 is "NG", the diagnostic result 23 of the first diagnostic circuit 21 is "OK", and the diagnostic result 33 of the second diagnostic circuit 31 is "NG", it can be determined that the second communication circuit 3 is faulty. Therefore, the switching function control unit 62 controls the first switching function unit 4 and the second switching function unit 5 so as to continue communication in the first communication circuit 2. In addition, the switching function control unit 62 outputs an abnormality notification 66 (2'b10) including fault information of the second communication circuit 3. Note that since the second communication circuit 3 is faulty, it is not possible to switch from the first communication circuit 2 to the second communication circuit 3. For this reason, although the redundant mode was assumed in this embodiment, the communication semiconductor device 1 is substantially configured as a non-redundant one.

[0044] As shown in record No. 3, when the diagnostic result 616 of the mutual diagnostic circuit 61 is "NG", the diagnostic result 23 of the first diagnostic circuit 21 is "NG", and the diagnostic result 33 of the second diagnostic circuit 31 is "OK", it can be determined that the first communication circuit 2 is faulty. Therefore, the switching function control unit 62 controls the first switching function unit 4 and the second switching function unit 5 to switch from the first communication circuit 2 to the second communication circuit 3 and perform communication. In addition, the switching function control unit 62 outputs an abnormality notification 66 (2'b01) indicating that the first communication circuit 2 is faulty.

[0045] As shown in record No. 4, when the diagnostic result 616 of the mutual diagnostic circuit 61 is "NG", the diagnostic result 23 of the first diagnostic circuit 21 is "OK", and the diagnostic result 33 of the second diagnostic circuit 31 is "OK", it is considered that one of the first diagnostic circuit 21, the second diagnostic circuit 31, and the mutual diagnostic circuit 61 is faulty. In this case, the switching function control unit 62 outputs an abnormality notification 66 (2'b11) indicating the suspension of communication. Then, the upper computer (for example, the microcomputer 7 in FIG. 17) that receives the abnormality notification 66 instructs the suspension of communication.

[0046] As shown in record No. 5, when the diagnosis result 616 of the mutual diagnosis circuit 61 is "OK", the diagnosis result 23 of the first diagnosis circuit 21 is "NG", and the diagnosis result 33 of the second diagnosis circuit 31 is "OK", it is considered that either the first diagnosis circuit 21 or the mutual diagnosis circuit 61 is faulty. In this case, the switching function control unit 62 outputs an abnormality notification 66 (2'b11) indicating the suspension of communication, and the communication is suspended.

[0047] As shown in record No. 6, when the diagnostic result 616 of the mutual diagnostic circuit 61 is "OK", the diagnostic result 23 of the first diagnostic circuit 21 is "OK", and the diagnostic result 33 of the second diagnostic circuit 31 is "NG", it is considered that either the second diagnostic circuit 31 or the mutual diagnostic circuit 61 is faulty. In this case, the switching function control unit 62 outputs an abnormality notification 66 (2'b11) indicating the suspension of communication, and the communication is suspended.

[0048] As shown in record No. 7, when the diagnostic result 616 of the mutual diagnostic circuit 61 is "OK", the diagnostic result 23 of the first diagnostic circuit 21 is "NG", and the diagnostic result 33 of the second diagnostic circuit 31 is "NG", it can be determined that both the first diagnostic circuit 21 and the second diagnostic circuit 31, or the mutual diagnostic circuit 61, are faulty. In this case, the switching function control unit 62 outputs an abnormality notification 66 (2'b11) indicating the suspension of communication, and the communication is suspended.

[0049] As shown in record No. 8, when the diagnostic result 616 of the mutual diagnostic circuit 61 is "NG", the diagnostic result 23 of the first diagnostic circuit 21 is "NG", and the diagnostic result 33 of the second diagnostic circuit 31 is "NG", it can be determined that both the first diagnostic circuit 21 and the second diagnostic circuit 31, or the mutual diagnostic circuit 61, are faulty. In this case, the switching function control unit 62 outputs an abnormality notification 66 (2'b11) indicating the suspension of communication, and the communication is suspended.

[0050] In this way, the switching function control section 62 of the control circuit 6 can detect failures in the first diagnostic circuit 21, the second diagnostic circuit 31, and the mutual diagnostic circuit 61 based on the diagnostic result 23 of the first diagnostic circuit 21, the diagnostic result 33 of the second diagnostic circuit 31, and the diagnostic result 616 of the mutual diagnostic circuit 61. Also, by referring to the self-diagnosis result (diagnosis results 23, 33) and the mutual diagnostic result (diagnosis result 616), the diagnostic accuracy can be improved. Note that the mutual diagnostic circuit 61 is not an essential component since it improves the diagnostic accuracy. The presence or absence of the mutual diagnostic circuit 61 may be determined depending on the degree of diagnostic accuracy required.

[0051] In addition, when the switching function control unit 62 detects an abnormality in any of the first communication circuit 2 and the second communication circuit 3, the diagnostic circuits 21, 31 of the first communication circuit 2 and the second communication circuit 3, and the mutual diagnostic circuit 61, it is configured to notify the communication partner of the communication semiconductor device 1 (for example, the microcontroller 7, the first IC 8, the second IC 9, etc. in Figure 17).

[0052] As a result, the communication source and / or destination of the communication semiconductor device 1 can check whether the communication is normal or not based on the presence or absence of the abnormality notification 66.

[0053] [Control process of the switching function control unit] Next, a control process procedure for the first switching function unit 4 and the second switching function unit 5 by the switching function control unit 62 of the control circuit 6 in the redundant mode will be described with reference to FIG.

[0054] Fig. 9 is a flowchart showing an example of a control process of the first switching function unit 4 and the second switching function unit 5 by the switching function control unit 62 of the control circuit 6 in the redundant mode. Here, the first communication circuit 2 is the main communication circuit, and the second communication circuit is the sub communication circuit. Note that for the switch settings and the abnormality notification contents shown in Fig. 9, refer to Figs. 6 and 7.

[0055] At the start of communication, the switching function control unit 62 performs switching control of the first switching function unit 4 and the second switching function unit 5 as in the switch setting "No. 1" shown in Fig. 6, thereby performing communication using the first communication circuit 2, which is the main communication circuit. Here, the switching function control unit 62 outputs "2'b00" as the abnormality notification 66 (S100). At this stage, the switching function control unit 62 determines that there are no abnormalities in the first communication circuit 2 and the second communication circuit 3, the first diagnostic circuit 21 and the second diagnostic circuit 31, and the mutual diagnostic circuit 61.

[0056] FIG. 10 shows a communication path when the first communication circuit 2 (main communication circuit) is used in the redundant mode. 10, the first switching function unit 4 inputs and outputs signals of the communication signal lines 11a and 11b of the first communication system to and from the first communication circuit 2. Similarly, the second switching function unit 5 inputs and outputs signals of the communication signal lines 11c and 11d of the first communication system to and from the first communication circuit 2.

[0057] Returning to the explanation of Fig. 9, the switching function control unit 62 next judges whether the diagnostic result 616 of the mutual diagnostic circuit 61, the diagnostic result 23 of the first diagnostic circuit 21, and the diagnostic result 33 of the second diagnostic circuit 31 are all OK (S101). Here, if the diagnostic results 23, 33, 616 of the respective diagnostic circuits are all OK (YES judgement in S101), it can be determined that the first communication circuit 2 and the second communication circuit 3 are operating normally.

[0058] Next, the switching function control unit 62 judges whether or not the communication has ended with the switch setting being "No. 1" and the abnormality notification 66 being "2'b00" (S107). If the communication has not ended (NO judgment in S107), the switching function control unit 62 returns to the judgment process of step S101 in which the diagnosis results of each diagnosis circuit are confirmed. If the communication has ended (YES judgment in S107), the switching function control unit 62 ends the process of this flowchart.

[0059] On the other hand, if any of the diagnostic results 23, 33, 616 of the diagnostic circuits is NG (NO judgment in S101), the switching function control unit 62 proceeds to step S102. Then, the switching function control unit 62 judges whether or not only the diagnostic result 23 of the first diagnostic circuit 21 is OK (S102).

[0060] When only the diagnosis result 23 of the first diagnostic circuit 21 is OK (YES judgment in S102), it is found that the first diagnostic circuit 21 and the second diagnostic circuit 31 are operating normally. Then, since only the diagnosis result 23 of the first diagnostic circuit 21 is OK, it is possible to determine that the second communication circuit 3 is faulty. Therefore, the switching function control unit 62 outputs "2'b10" as the abnormality notification 66 while keeping the switch setting at "No.1" (S103), and then proceeds to step S107. Then, in step S107, the switching function control unit 62 judges whether or not the communication has ended with the switch setting at "No.1" and the abnormality notification 66 at "2'b10".

[0061] On the other hand, if only the diagnosis result 23 of the first diagnostic circuit 21 is not OK (NO in S102), the switching function control unit 62 proceeds to step S104. Then, the switching function control unit 62 determines whether only the diagnosis result 33 of the second diagnostic circuit 31 is OK (S104).

[0062] When only the diagnostic result 33 of the second diagnostic circuit 31 is OK (YES judgment in S104), it is found that the first diagnostic circuit 21 and the second diagnostic circuit 31 are operating normally. And, since only the diagnostic result 33 of the second diagnostic circuit 31 is OK, it is possible to determine that the first communication circuit 2 is faulty.

[0063] At that time, in order not to stop the communication, the switching function control unit 62 performs switching control as in the switch setting "No. 2" shown in Fig. 6, and continues the communication using the second communication circuit 3, which is a sub-communication circuit. In addition, the switching function control unit 62 outputs "2'b01" as the abnormality notification 66 (S105), and then proceeds to step S107.

[0064] FIG. 11 shows a communication path when the first communication circuit 2 fails in the redundant mode. By changing the switch setting to "No. 2", the first switching function unit 4 inputs / outputs the signals of the communication signal lines 11a and 11b of the first communication system to / from the second communication circuit 3 (sub-communication circuit), as shown by the bold line in Fig. 11. Similarly, the second switching function unit 5 inputs / outputs the signals of the communication signal lines 11c and 11d of the first communication system to / from the second communication circuit 3.

[0065] Returning to the description of Fig. 9, in step S107, the switching function control unit 62 determines whether or not communication has ended with the switch setting being "No. 2" and the abnormality notification 66 being "2'b01".

[0066] On the other hand, if only the diagnosis result 33 of the second diagnostic circuit 31 is not OK (NO judgment in S104), the switching function control unit 62 proceeds to step S106. In this case, since a failure is assumed in any of the first diagnostic circuit 21, the second diagnostic circuit 31, and the mutual diagnostic circuit 61, the switching function control unit 62 stops communication and outputs "2'b11" as the abnormality notification 66 (S106). Since communication by the current communication circuit (e.g., the first communication circuit 2) is stopped and switching to the sub communication circuit (e.g., the second communication circuit 3) is not performed, communication by the communication semiconductor device 1 is stopped. After the process of step S106, the switching function control unit 62 ends the process of this flowchart.

[0067] As described above, the communication semiconductor device according to the first embodiment includes a first communication circuit that performs a predetermined operation in response to a signal input and outputs a signal, a second communication circuit that performs a predetermined operation in response to a signal input and outputs a signal, a first switching function unit connected to one end of the first communication circuit and the second communication circuit and switching a signal input destination and an output source for the first communication circuit and the second communication circuit, a second switching function unit connected to the other end of the first communication circuit and the second communication circuit and switching a signal input destination and an output source for the first communication circuit and the second communication circuit, diagnostic circuits (first diagnostic circuit, second diagnostic circuit) provided in each of the first communication circuit and the second communication circuit and that diagnose the first communication circuit and the second communication circuit, and control circuits connected to the first communication circuit and the second communication circuit, and the first switching function unit and the second switching function unit. The control circuit has a switching function control unit that issues switching instructions for the input destination and output source to the first switching function unit and the second switching function unit based on a redundant / non-redundant mode switching signal indicating an operating mode input from outside and the diagnostic results of each diagnostic circuit.

[0068] The communication semiconductor device according to the first embodiment thus configured includes a first communication circuit and a second communication circuit, and a first switching function unit and a second switching function unit for switching signal paths, and controls the first switching function unit and the second switching function unit based on a redundant / non-redundant mode switching signal and the states of the first communication circuit and the second communication circuit (the diagnosis results of each diagnosis circuit). As a result, the communication semiconductor device according to this embodiment includes a redundant function, and can configure a non-redundant system when the redundant function is not required. As a result, the communication semiconductor device according to the first embodiment can be used with either one or two communication systems.

[0069] The communication semiconductor device according to this embodiment is capable of switching the input destination and output source of each communication circuit (first communication circuit, second communication circuit) by the first switching function unit and the second switching function unit. Therefore, based on the redundant / non-redundant mode switching signal and the states of the first communication circuit and the second communication circuit (diagnosis results of each diagnostic circuit), a redundant system can be configured for a system requiring a redundant function (redundant mode), and a non-redundant system can be configured for a system not requiring a redundant function (non-redundant mode).

[0070] For example, when a redundant system is configured, the communication semiconductor device according to this embodiment can switch to a sub communication circuit (e.g., a second communication circuit) without interrupting communication when an abnormality occurs in a main communication circuit (e.g., a first communication circuit). This prevents the system from being stopped when an abnormality occurs, thereby contributing to functional safety and improved reliability.

[0071] Furthermore, when the communication semiconductor device according to this embodiment is configured as a non-redundant system, each communication circuit can communicate with an independent communication system (first communication system, second communication system). This allows for reduced hardware and therefore reduced costs.

[0072] In addition, the communication semiconductor device of this embodiment is equipped with a self-diagnosis function (first diagnostic circuit, second diagnostic circuit) in each communication circuit, so that it is possible to diagnose whether there is a fault in the standby communication circuit (e.g., the second communication circuit) before switching.

[0073] Furthermore, the communication semiconductor device according to this embodiment is provided with a mutual diagnosis function (mutual diagnosis circuit) in the control circuit that compares the input / output of each communication circuit, making it possible to determine whether each diagnosis circuit is normal. Therefore, the communication semiconductor device according to this embodiment can improve the diagnostic accuracy of each communication circuit.

[0074] [SOI structure, SIP structure] In order to prevent the first communication circuit 2 and the second communication circuit 3 from being destroyed simultaneously, it is desirable for the communication semiconductor device 1 to have an SOI (Silicon On Insulator) structure or a SIP (System In a Package) structure, as shown in FIG. 12.

[0075] FIG. 12 is a diagram showing an example of an IC (Integrated Circuit) configuration for avoiding simultaneous destruction of the first communication circuit 2 and the second communication circuit 3 as a configuration of the communication semiconductor device 1. In FIG. In the SOI structure, for example, a silicon dioxide (SiO2) film is used to separate semiconductor elements on an SOI substrate (a Si substrate as an example). As shown on the left side of Fig. 12, at least a component in which semiconductor elements constituting a main communication circuit (e.g., a first communication circuit 2) are integrated and a component in which semiconductor elements constituting a sub communication circuit (e.g., a second communication circuit 3) are integrated are separated from each other via a SiO2 film.

[0076] For example, one form of separation by the SiO2 film of the SOI structure may be separation based on a first component in which semiconductor elements constituting the "first communication circuit 2" are integrated, a second component in which semiconductor elements constituting the "second communication circuit 3" are integrated, and a third component in which semiconductor elements constituting each of the "first switching function unit 4, second switching function unit 5, and control circuit 6" are integrated. Furthermore, the third component may be divided into smaller units by any combination of the "first switching function unit 4," the "second switching function unit 5," and the "control circuit 6."

[0077] In the SIP structure, for example, multiple semiconductor chips are arranged on a lead frame (packaging material) and sealed in one package. As shown on the right side of Fig. 12, at least a semiconductor chip on which a semiconductor element constituting a main communication circuit (e.g., the first communication circuit 2) is integrated is separated from a semiconductor chip on which a semiconductor element constituting a sub communication circuit (e.g., the second communication circuit 3) is integrated.

[0078] For example, one form of separation using a SIP structure is to seal in the same package a first semiconductor chip integrating the "first communication circuit 2", a second semiconductor chip integrating the "second communication circuit 3", and a third semiconductor chip integrating the first switching function unit 4, the second switching function unit 5, and the control circuit 6. Also, the third semiconductor chip may be further divided into multiple semiconductor chips by any combination of the "first switching function unit 4", the "second switching function unit 5", and the "control circuit 6".

[0079] As described above, by employing the SOI structure or SIP structure for the communication semiconductor device 1, it is possible to physically and electrically separate at least the first communication circuit 2 and the second communication circuit 3, and prevent a failure in one communication circuit from affecting another communication circuit. In the second to fourth embodiments described later as well, it is desirable to employ the SOI structure or SIP structure for the communication semiconductor device.

[0080] <Second embodiment> The second embodiment is an example in which the first switching function unit 4 and the second switching function unit 5 are controlled so that the first communication circuit 2 and the second communication circuit 3 operate independently in the non-redundant mode. The second embodiment is also an example in which the first switching function unit 4 and the second switching function unit 5 are controlled so as to continue the communication system of the communication circuit with a higher priority.

[0081] The configuration of the communication semiconductor device in the second embodiment is the same as that of the communication semiconductor device 1 according to the first embodiment (see FIGS. 1 to 5). However, in the second embodiment, the diagnosis result 616 of the mutual diagnosis circuit 61 included in the control circuit 6 is not used.

[0082] [Diagnostic results of each diagnostic circuit and control in the switching function control section] FIG. 13 is a diagram showing an example of the diagnostic results of each diagnostic circuit in the non-redundant mode and the control in the switching function control unit 62. In FIG. The illustrated table 72 has the following items: "No.", "Diagnosis result of first diagnostic circuit", "Diagnosis result of second diagnostic circuit", and "Control in switching function control section". Note that in FIG. 13, the contents of the control in the switching function control section 62 are premised on the independent use of multiple communication systems in the non-redundant mode. Also, the priority stored in the memory 62m of the switching function control section 62 is such that the first communication circuit 2 has a higher priority than the second communication circuit 3.

[0083] As shown in record No. 1, when the diagnostic result 23 of the first diagnostic circuit 21 is "OK" and the diagnostic result 33 of the second diagnostic circuit 31 is "OK", it can be determined that both the first communication circuit 2 and the second communication circuit 3 are normal. Therefore, the switching function control unit 62 continues communication using the first communication circuit 2 and the second communication circuit 3 independently.

[0084] As shown in record No. 2, when the diagnosis result 23 of the first diagnostic circuit 21 is "OK" and the diagnosis result 33 of the second diagnostic circuit 31 is "NG", it can be determined that the second communication circuit 3 is faulty. Therefore, the switching function control unit 62 outputs an abnormality notification 66 (2'b10) including fault information of the second communication circuit 3, and stops communication by the second communication circuit 3. In addition, the switching function control unit 62 controls the first switching function unit 4 and the second switching function unit 5 so as to continue communication by the first communication circuit 2 which has a higher priority.

[0085] As shown in record No. 3, when the diagnosis result 23 of the first diagnostic circuit 21 is "NG" and the diagnosis result 33 of the second diagnostic circuit 31 is "OK", it can be determined that the first communication circuit 2 is faulty. Therefore, the switching function control unit 62 switches to the second communication circuit 3, which has a lower priority, and continues communication. At this time, the switching function control unit 62 outputs an abnormality notification 66 (2'b01) including fault information of the first communication circuit 2, and cuts off the communication system that was originally communicating via the second communication circuit 3.

[0086] Although not shown in FIG. 13, if the diagnostic result 23 of the first diagnostic circuit 21 is "NG" and the diagnostic result 33 of the second diagnostic circuit 31 is "NG", it can be determined that both the first communication circuit 2 and the second communication circuit 3 are faulty.

[0087] [Control process of the switching function control unit] Next, a procedure of the control process of the first switching function unit 4 and the second switching function unit 5 by the switching function control unit 62 of the control circuit 6 in the non-redundant mode will be described with reference to FIG.

[0088] Fig. 14 is a flowchart showing an example of a control process of the first switching function unit 4 and the second switching function unit 5 by the switching function control unit 62 of the control circuit 6 in the non-redundant mode. Here, an operation when the first communication circuit 2 and the second communication circuit 3 communicate independently when the operation mode of the communication semiconductor device 1 is set to the non-redundant mode will be described. Also, a case where the priority of each communication circuit is equal and a case where the first communication circuit 2 has a higher priority than the second communication circuit 3 will be described. Note that Figs. 6 and 7 are referred to for the switch settings and abnormality notification contents shown in Fig. 14.

[0089] The redundant mode described in the first embodiment is a single-system communication, whereas the non-redundant mode is a two-system communication that is performed independently. Therefore, Figs. 1 to 7 and 12 referred to in the first embodiment can also be referred to in this embodiment, but the following points are different between this embodiment and the second embodiment. The difference is that in this embodiment, a second communication system (communication signal lines 12a to 12d) is added to the communication semiconductor device 1 in Fig. 1, and the switching function control unit 62 has a function (memory 62m) for storing priority information of each communication circuit.

[0090] At the start of communication, the switching function control unit 62 controls the switching of the first switching function unit 4 and the second switching function unit 5 as in the switch setting "No. 3" shown in Fig. 6, so that the first communication circuit 2 communicates through the first communication system (communication signal lines 11a to 11d) and the second communication circuit 3 communicates through the second communication system (communication signal lines 12a to 12d). The switching function control unit 62 outputs "2'b00" as the abnormality notification 66 (S200).

[0091] FIG. 15 shows a communication path when the first communication circuit 2 and the second communication circuit 3 are used in the non-redundant mode. 15, the first switching function unit 4 inputs / outputs the signals of the communication signal lines 11a and 11b of the first communication system to / from the first communication circuit 2, and inputs / outputs the signals of the communication signal lines 12a and 12b of the second communication system to / from the second communication circuit 3. Similarly, the second switching function unit 5 inputs / outputs the signals of the communication signal lines 11c and 11d of the first communication system to / from the first communication circuit 2, and inputs / outputs the signals of the communication signal lines 12c and 12d of the second communication system to / from the second communication circuit 3.

[0092] Returning to the explanation of Fig. 14, the switching function control unit 62 next judges whether the diagnostic result 23 of the first diagnostic circuit 21 and the diagnostic result 33 of the second diagnostic circuit 31 are all OK (S201). If the diagnostic results 23, 33 of the respective diagnostic circuits are all OK (YES judgement in S201), it can be determined that the first communication circuit 2 and the second communication circuit 3 are operating normally.

[0093] Next, the switching function control unit 62 judges whether or not the communication has ended with the switch setting being "No. 3" and the abnormality notification 66 being "2'b00" (S207). If the communication has not ended (NO judgment in S207), the switching function control unit 62 returns to the judgment process of step S201 in which the diagnosis results of each diagnosis circuit are confirmed. If the communication has ended (YES judgment in S207), the switching function control unit 62 ends the process of this flowchart.

[0094] On the other hand, if any of the diagnostic results 23, 33 of the diagnostic circuits is NG (NO judgment in S201), the switching function control unit 62 proceeds to step S202. Then, the switching function control unit 62 judges whether or not only the diagnostic result 23 of the first diagnostic circuit 21 is OK (S202).

[0095] If only the diagnosis result 23 of the first diagnosis circuit 21 is OK (YES in S202), it can be determined that the second communication circuit 3 is faulty. Therefore, the switching function control unit 62 leaves the switch setting at "No. 3", outputs "2'b10" as the abnormality notification 66 (S203), and stops communication in the second communication system (communication signal lines 12a to 12d) upon receiving an instruction from a higher-level computer (for example, the microcomputer 7).

[0096] After the process of step S203, the switching function control unit 62 proceeds to step S207. In step S207, the switching function control unit 62 determines whether or not communication has ended with the switch setting being "No. 3" and the abnormality notification 66 being "2'b10".

[0097] On the other hand, if only the diagnosis result 23 of the first diagnostic circuit 21 is not OK (NO in S202), the switching function control unit 62 proceeds to step S204. Then, the switching function control unit 62 determines whether only the diagnosis result 33 of the second diagnostic circuit 31 is OK (S204).

[0098] If only the diagnosis result 33 of the second diagnosis circuit 31 is OK (YES in S204), it can be determined that the first communication circuit 2 is faulty. At that time, if the priorities of the first communication circuit 2 and the second communication circuit 3 stored in the memory 62m are equal, the switching function control unit 62 does not change the switch setting to "No. 3", outputs "2'b01" as the abnormality notification 66, and stops communication of the first communication system (communication signal lines 11a to 11d) upon receiving an instruction from a higher-level computer (e.g., the microcomputer 7) (S205).

[0099] On the other hand, when the first communication circuit 2 has a higher priority, in order to continue the communication of the first communication system, the switching function control unit 62 performs switching control as in the switch setting "No. 2" shown in Fig. 6 and outputs "2'b01" as the abnormality notification 66 (S205). At this time, due to the switching, the signals of the second communication system (communication signal lines 12a to 12d) are not input to or output from any of the communication circuits, so the switching function control unit 62 stops the communication using the second communication system. Alternatively, the communication of the second communication system may be stopped after receiving an instruction from a higher-level computer (for example, the microcomputer 7).

[0100] FIG. 16 shows a communication path when the first communication circuit 2 with higher priority fails in the non-redundant mode. The switch setting "No.2" after switching following a failure of the first communication circuit 2 is the same as the switch setting "No.2" after switching in the redundant mode (FIG. 11). That is, by changing the switch setting to "No.2", as shown by the bold line in FIG. 16, the first switching function unit 4 inputs / outputs signals on the communication signal lines 11a and 11b of the first communication system to / from the second communication circuit 3 (sub-communication circuit). Similarly, the second switching function unit 5 inputs / outputs signals on the communication signal lines 11c and 11d of the first communication system to / from the second communication circuit 3. As a result of this switching, signals of the second communication system are not input / output to / from any of the communication circuits.

[0101] Returning to the description of Fig. 14, after the process of step S205, the switching function control unit 62 proceeds to step S207. In step S207, the switching function control unit 62 determines whether or not communication has ended with the switch setting being "No. 3" or "No. 2" and the abnormality notification 66 being "2'b01".

[0102] On the other hand, if only the diagnosis result 33 of the second diagnosis circuit 31 is not OK (NO judgment in S204), the switching function control unit 62 proceeds to step S206. In this case, since it is assumed that both the first communication circuit 2 and the second communication circuit 3 are faulty, the switching function control unit 62 stops communication of the first communication system and the second communication system, and outputs "2'b11" as the abnormality notification 66 (S206). After the process of step S206, the switching function control unit 62 ends the process of this flowchart.

[0103] As described above, in the communication semiconductor device of the second embodiment, when the operating mode is the non-redundant mode, the switching function control unit is configured to switch the input path and output path of the first switching function unit and the second switching function unit so that different signals are input to the first communication circuit and the second communication circuit, respectively, and signals corresponding to the different signals are output from the first communication circuit and the second communication circuit, respectively.

[0104] The communication semiconductor device according to this embodiment configured as described above can configure a non-redundant system for a system (non-redundant mode) that does not require a redundancy function based on the operation mode (redundant / non-redundant mode switching signal 63). This allows the communication semiconductor device according to this embodiment to use two communication systems (first communication system and second communication system) independently in the non-redundant mode.

[0105] In addition, in the communication semiconductor device according to the second embodiment, information on the priority of the first communication circuit and the second communication circuit is stored in a switching function control unit (for example, a memory 62m).The switching function control unit is configured to switch the input path and output path of the first switching function unit and the second switching function unit when a communication circuit with a higher priority out of the first communication circuit and the second communication circuit fails so that communication can be continued using the communication circuit with a lower priority.

[0106] The communication semiconductor device of this embodiment configured as described above can continue communication without stopping communication using the high priority communication circuit (communication system) by switching to the other communication circuit (second communication circuit 3) when the high priority communication circuit (first communication circuit 2) fails.

[0107] In addition, in the communication semiconductor device of the second embodiment, when the first communication circuit and the second communication circuit have equal priority, when the first communication circuit or the second communication circuit fails, only communication using the failed first communication circuit or second communication circuit is discontinued.

[0108] The communication semiconductor device of this embodiment configured as described above is able to continue communication using the non-faulty communication circuit by suspending only the communication using the faulty first or second communication circuit.

[0109] <Third embodiment> The third embodiment is an example in which the communication semiconductor device 1 is used as a CAN I / F, which is one of in-vehicle LAN protocols.

[0110] [The first and second ICs are connected to different CAN buses] FIG. 17 is a diagram showing an example of a case where a first IC and a second IC are connected to different CAN buses in a system using the communication semiconductor device 1 according to the third embodiment as a CAN I / F.

[0111] The first switching function unit 4 of the communication semiconductor device 1 shown in the figure is connected to a microcomputer 7, which is a higher-level computer. The microcomputer 7 and the communication semiconductor device 1 can communicate with each other using a first communication system (communication signal lines 11a-11b) and a second communication system (communication signal lines 12a-12b). The microcomputer 7 and the communication semiconductor device 1 are mounted on the same ECU 100. For example, each of the microcomputer 7 and the communication semiconductor device 1 corresponds to an ECU, and the ECU 100 corresponds to an integrated ECU.

[0112] The microcomputer 7 is, for example, a computer equipped with a processor such as a CPU, memories such as a ROM and a RAM, and a communication circuit. The functions of the microcomputer 7 described in this specification may be realized by software, in which the processor interprets and executes a program that realizes each function. The relevant programs, tables, and other information may be stored in a recording medium such as a memory.

[0113] The second switching function unit 5 of the communication semiconductor device 1 is connected to the first IC 8 via the CAN bus 10A and is connected to the second IC 9 via the CAN bus 10B. The communication semiconductor device 1 and the first IC 8 can communicate with each other using a first communication system (communication signal lines 11c to 11d, CAN bus 10B). The communication semiconductor device 1 and the second IC 9 can communicate with each other using the first communication system (communication signal lines 11c to 11d, CAN bus 10B). The first IC 8 and the second IC 9 each correspond to an in-vehicle sensor or the like.

[0114] 17 has the same configuration and operates in the same manner as the communication semiconductor device 1 in the second embodiment. A microcomputer 7 communicates with a first IC 8 and a second IC 9 via the communication semiconductor device 1.

[0115] For example, in the non-redundant mode, when the first communication circuit 2 and the second communication circuit 3 have the same priority, communication between the microcomputer 7 and the first IC 8 is performed using the first communication circuit 2. Also, communication between the microcomputer 7 and the second IC 9 is performed using the second communication circuit 3. The communication semiconductor device 1 shown in FIG. 17 performs the same operation as when the communication circuits in the second embodiment have the same priority.

[0116] Furthermore, in the non-redundant mode, when the first communication circuit 2 has a higher priority than the second communication circuit 3, if the first communication circuit 2 fails, the switches S1 to S6 of the first switching function unit 4 and the second switching function unit 5 are switched so as not to stop communication. Then, the second communication circuit 3 is used to communicate between the microcomputer 7 and the first IC 8, and the same operation as when the first communication circuit 2 has a higher priority in the second embodiment is performed.

[0117] [The first and second ICs are connected to the same CAN bus] FIG. 18 is a diagram showing an example of a case where a first IC and a second IC are connected to the same CAN bus in a system using a communication semiconductor device 1B according to the third embodiment as a CAN I / F.

[0118] The first IC8 and the second IC9 are connected to the same CAN bus 10. Even if the first communication circuit 2 or the second communication circuit 3 fails, the communication semiconductor device 1B can communicate with the first IC8 and the second IC9 by accessing the CAN bus 10, so the second switching function unit 5 is omitted in FIG. 18. The rest of the configuration of the communication semiconductor device 1B is the same as that of the communication semiconductor device 1 shown in FIG. 1. The operation of the communication semiconductor device 1B in the case where the two ICs, the first IC8 and the second IC9, are connected to the same CAN bus 10 as shown in FIG. 18 will be described with reference to FIGS. 19 and 20.

[0119] FIG. 19 is a diagram showing an example of the configuration of a switching content table T2 in which switching contents of the first switching function unit 4 according to the third embodiment are recorded. The switching content table T2 has the items of “type of switching function unit”, “type of switch”, and “switch setting (connection switching)”. The switching content of the first switching function unit 4 described in the switching content table T2 is the same as the switch settings “No. 1” and “No. 2” of the switches S1 to S3 included in the first switching function unit 4 described in the switching content table T1 of FIG.

[0120] [Control process of the switching function control unit] Next, a procedure of a control process of the first switching function unit 4 and the second switching function unit 5 by the switching function control unit 62 of the control circuit 6 according to the third embodiment will be described with reference to FIG.

[0121] Fig. 20 is a flowchart showing an example of a control process of the first switching function unit 4 by the switching function control unit 62 of the control circuit 6 in the communication semiconductor device 1 shown in Fig. 18. For the contents of the switch settings and abnormality notification shown in Fig. 20, refer to Figs. 19 and 7.

[0122] At the start of communication, the switching function control unit 62 controls the first switching function unit 4 to switch in the manner of the switch setting "No. 1" shown in Fig. 19, so that the first communication circuit 2 communicates through the first communication system (communication signal lines 11a to 11d) and the second communication circuit 3 communicates through the second communication system (communication signal lines 12a to 12d). The switching function control unit 62 outputs "2'b00" as the abnormality notification 66 (S300).

[0123] Next, the switching function control unit 62 judges whether the diagnostic result 23 of the first diagnostic circuit 21 and the diagnostic result 33 of the second diagnostic circuit 31 are all OK (S301). If the diagnostic results 23, 33 of the respective diagnostic circuits are all OK (YES judgment in S301), it can be determined that the first communication circuit 2 and the second communication circuit 3 are operating normally.

[0124] Next, the switching function control unit 62 judges whether or not the communication has ended with the switch setting being "No. 1" and the abnormality notification 66 being "2'b00" (S307). If the communication has not ended (NO judgment in S307), the switching function control unit 62 returns to the judgment process of step S301 in which the diagnosis results of each diagnosis circuit are confirmed. If the communication has ended (YES judgment in S307), the switching function control unit 62 ends the process of this flowchart.

[0125] On the other hand, if either of the diagnostic results 23, 33 of the diagnostic circuits is NG (NO judgment in S301), the switching function control unit 62 proceeds to step S302. Then, the switching function control unit 62 judges whether or not only the diagnostic result 23 of the first diagnostic circuit 21 is OK (S302).

[0126] If only the diagnosis result 23 of the first diagnosis circuit 21 is OK (YES in S302), it can be determined that the second communication circuit 3 is faulty. Therefore, the switching function control unit 62 leaves the switch setting at "No. 1", outputs "2'b10" as the abnormality notification 66 (S303), and stops communication in the second communication system (communication signal lines 12a to 12d) upon receiving an instruction from a higher-level computer (for example, the microcomputer 7).

[0127] After the process of step S303, the switching function control unit 62 proceeds to step S307. In step S307, the switching function control unit 62 determines whether or not communication has ended with the switch setting being "No. 1" and the abnormality notification 66 being "2'b10".

[0128] On the other hand, if only the diagnosis result 23 of the first diagnostic circuit 21 is not OK (NO in S302), the switching function control unit 62 proceeds to step S304. Then, the switching function control unit 62 determines whether only the diagnosis result 33 of the second diagnostic circuit 31 is OK (S304).

[0129] If only the diagnosis result 33 of the second diagnosis circuit 31 is OK (YES in S304), it can be determined that the first communication circuit 2 is faulty. At that time, if the priorities of the first communication circuit 2 and the second communication circuit 3 stored in the memory 62m are equal, the switching function control unit 62 does not change the switch setting to "No. 1" and outputs "2'b01" as the abnormality notification 66. Then, the switching function control unit 62 receives an instruction from a higher-level computer (e.g., the microcomputer 7) and stops communication of the first communication system (communication signal lines 11a to 11d) (S305).

[0130] On the other hand, when the first communication circuit 2 has a higher priority, in order to continue the communication of the first communication system, the switching function control unit 62 performs switching control as in the switch setting "No. 2" shown in FIG. 19, and outputs "2'b01" as the abnormality notification 66 (S305). At this time, due to the switching, the signal of the second communication system (communication signal lines 12a to 12b) is not input to or output from any of the communication circuits (see FIG. 16), so the switching function control unit 62 stops the communication using the second communication system. Alternatively, the communication of the second communication system may be stopped after receiving an instruction from a higher-level computer (for example, the microcomputer 7).

[0131] After the process of step S305, the switching function control unit 62 proceeds to step S307. In step S307, the switching function control unit 62 determines whether or not communication has ended with the switch setting being "No. 1" or "No. 2" and the abnormality notification 66 being "2'b01".

[0132] On the other hand, if only the diagnosis result 33 of the second diagnosis circuit 31 is not OK (NO judgment in S304), the switching function control unit 62 proceeds to step S306. In this case, since it is assumed that both the first communication circuit 2 and the second communication circuit 3 are faulty, the switching function control unit 62 stops communication of the first communication system and the second communication system, and outputs "2'b11" as the abnormality notification 66 (S306). After processing in step S306, the switching function control unit 62 ends the processing of this flowchart.

[0133] As described above, the communication semiconductor devices 1 and 1B according to the third embodiment can be used as a CAN I / F, and therefore can be applied to in-vehicle applications. Furthermore, in the communication semiconductor devices 1 and 1B, when an abnormality occurs in a main communication circuit (e.g., the first communication circuit 2), the communication can be switched to a sub communication circuit (e.g., the second communication circuit 3) without interrupting communication, which contributes to functional safety and improved reliability in the in-vehicle field as well. For example, the communication semiconductor devices 1 and 1B mounted on the ECU 100, which corresponds to an integrated ECU, have a redundant function, which enables the ECU 100 to meet functional safety and improve reliability.

[0134] <Fourth embodiment> Next, an example will be described in which a cutoff request is made to an upstream power supply circuit according to the states of the first communication circuit 2 and the second communication circuit 3 of the communication semiconductor device as a means for avoiding electrical breakdown, explosion, or combustion that can be a common cause failure. Note that the first to third embodiments are referred to for the method of determining the states of the first communication circuit 2 and the second communication circuit 3.

[0135] FIG. 21 is a block diagram showing an example of a configuration of a communications semiconductor device 1C according to the fourth embodiment. The basic configuration of the communication semiconductor device 1C in this embodiment is the same as that of the communication semiconductor device 1 (FIG. 1) according to the first embodiment. However, the communication semiconductor device 1C has been added to the communication semiconductor device 1 in FIG. 1 with a first power supply 22 of the first communication circuit 2, a second power supply 32 of the second communication circuit 3, a cutoff request 67 (first power cutoff request) for the first power supply 22, and a cutoff request 68 (second power cutoff request) for the second power supply 32. These details will be described with reference to FIG. 22.

[0136] FIG. 22 is a diagram showing an example of a shutoff request to a higher-level power supply circuit (not shown). In this embodiment, the shutdown requests 67 and 68 are 1-bit signals, and "1'b0" shown in Fig. 22 means that the shutdown request is invalid, and "1'b1" means that the shutdown request is valid. The communication semiconductor device 1C executes a power shutdown request in parallel with the switching control of the first switching function unit 4 and the second switching function unit 5 based on the state of each communication circuit.

[0137] When both the first communication circuit 2 and the second communication circuit 3 are normal, the shutoff request 67 of the first power supply 22 and the shutoff request 68 of the second power supply 32 output “1′b0”, and the power supply to both communication circuits is not shut off.

[0138] When only the first communication circuit 2 fails, only the shutoff request 67 of the first power source 22 outputs “1′b1”, and the upstream power source circuit that receives the shutoff request 67 of the first power source 22 shuts off the first power source 22.

[0139] When only the second communication circuit 3 fails, only the shutoff request 68 for the second power source 32 outputs “1′b1”, and the upstream power supply circuit that receives the shutoff request 68 for the second power source 32 shuts off the second power source 32 .

[0140] When both the first communication circuit 2 and the second communication circuit 3 fail, the shutoff request 67 of the first power supply 22 and the shutoff request 68 of the second power supply 32 output "1'b1". Then, the upstream power supply circuit that receives the shutoff request 67 of the first power supply 22 and the shutoff request 68 of the second power supply 32 shuts off the first power supply 22 and the second power supply 32. For other configurations and operations of the communication semiconductor device 1C, refer to the first to third embodiments.

[0141] As described above, in the communication semiconductor device of the fourth embodiment, the switching function control unit is configured to request a cut-off of the power supply circuit that supplies power to the communication semiconductor device when a fault is detected in each diagnostic circuit (first diagnostic circuit 21, second diagnostic circuit 31) of the first communication circuit and the second communication circuit.

[0142] The communication semiconductor device according to the fourth embodiment configured as described above can avoid common cause failures by cutting off the power supply by issuing a cutoff request to the power supply circuit when a failure occurs in each communication circuit. By cutting off the power supply when a failure occurs in any component included in the communication semiconductor device, it is possible to avoid common cause failures, which are an issue when a function consisting of a redundant configuration using two communication circuits is integrated into an integrated circuit.

[0143] It should be noted that the present invention is not limited to the first to fourth embodiments described above, and it goes without saying that various other applications and modifications are possible without departing from the gist of the present invention as set forth in the claims. For example, each of the above-described embodiments describes in detail and specifically the configuration of a communication semiconductor device in order to easily explain the present invention, and is not necessarily limited to having all of the components described. Also, it is possible to replace a part of the configuration of one embodiment with a component of another embodiment. Also, it is possible to add a component of another embodiment to the configuration of one embodiment. Also, it is possible to add, replace, or delete other components from a part of the configuration of each embodiment.

[0144] In addition, the above-mentioned configurations, functions, processing units, etc. may be realized in part or in whole by hardware, for example, by designing them as integrated circuits. As the hardware, a broad processor device such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit) may be used.

[0145] In addition, in the flowcharts describing the time-series processing shown in Figures 9, 14, and 20, multiple processes may be executed in parallel or the processing order may be changed as long as it does not affect the processing results.

[0146] In the above-described embodiment, the control lines and information lines are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. In reality, it may be considered that almost all components are connected to each other. [Explanation of symbols]

[0147] 1, 1B, 1C...communication semiconductor device, 11a to 11d...communication signal line (first communication system), 12a to 12d...communication signal line (second communication system), 2...first communication circuit, 2a to 2d...communication signal line, 21...first diagnostic circuit, 23...diagnosis result of first diagnostic circuit, 24...transmitter, 25...receiver, 211...diagnostic receiver, 212, 213...comparator, 214...logical OR circuit, 215...output of diagnostic receiver, 2a to 2d...communication signal line of first communication circuit, 3...second communication circuit, 31...second diagnostic circuit, 33...diagnosis result of second diagnostic circuit, 3a to 3d...communication signal line of second communication circuit, 4...first switching function unit, 5...second switching function unit, 6 ...Control circuit, 61...Mutual diagnosis circuit, 62...Switching function control section, 62m...Memory, 63...Redundant / non-redundant mode switching signal, 64...Control signal of first switching function section, 65...Control signal of second switching function section, 66...Abnormality notification, 67...First power cut-off request, 68...Second power cut-off request, 611, 612...Comparator, 613...Logical OR circuit, 614...Comparator output, 615...Comparator output, 616...Mutual diagnosis circuit output, 7...Microcomputer, 8...First IC, 9...Second IC, 100...ECU, S1...First switch, S2...Second switch, S3...Third switch, S4...Fourth switch, S5...Fifth switch, S6...Sixth switch, T1, T2...Switching content table

Claims

1. a first communication circuit that performs a predetermined operation in response to a signal input and outputs a signal; a second communication circuit that performs a predetermined operation in response to a signal input and outputs a signal; a first switching function unit connected to one end of the first communication circuit and the second communication circuit and configured to switch an input destination and an output source of a signal for the first communication circuit and the second communication circuit; a second switching function unit connected to the other ends of the first communication circuit and the second communication circuit and configured to switch an input destination and an output source of the signal with respect to the first communication circuit and the second communication circuit; a diagnostic circuit provided in each of the first communication circuit and the second communication circuit, the diagnostic circuit diagnosing the first communication circuit and the second communication circuit; a control circuit connected to the first communication circuit, the second communication circuit, and the first switching function unit and the second switching function unit; the control circuit includes a switching function control unit that issues switching instructions of an input destination and an output source to the first switching function unit and the second switching function unit based on a redundant / non-redundant mode switching signal indicating an operation mode input from outside and on a diagnosis result of each diagnosis circuit; the first communication circuit and the second communication circuit each have a transmitter and a receiver; The diagnostic circuits of the first communication circuit and the second communication circuit compare information input to the transmitter with information output from the receiver to diagnose the first communication circuit and the second communication circuit, respectively. Communications semiconductor device.

2. When the operation mode is a redundant mode, the signal input to the first communication circuit and the second communication circuit is the same signal.

2. The communications semiconductor device according to claim 1.

3. The control circuit includes: a mutual diagnosis circuit that, when the operation mode is a redundant mode, compares the first communication circuit and the second communication circuit with each other based on input information and output information of the first communication circuit and the second communication circuit, and outputs a comparison result to the switching function control unit.

3. The communication semiconductor device according to claim 1.

4. The mutual diagnosis circuit compares information input to the transmitter of the first communication circuit with information output from the receiver of the second communication circuit, and also compares information input to the transmitter of the second communication circuit with information output from the receiver of the first communication circuit, thereby mutually diagnosing the first communication circuit and the second communication circuit.

4. The communication semiconductor device according to claim 3.

5. The switching function control unit switches the input path and the output path of signals in the first switching function unit and the second switching function unit based on a diagnosis result of the mutual diagnosis circuit and diagnosis results of each diagnosis circuit included in the first communication circuit and the second communication circuit.

5. The communication semiconductor device according to claim 4.

6. When the operation mode is a non-redundant mode, the switching function control unit switches the input path and the output path of the first switching function unit and the second switching function unit so that different signals are input to the first communication circuit and the second communication circuit, respectively, and signals corresponding to the different signals are output from the first communication circuit and the second communication circuit, respectively.

6. The communication semiconductor device according to claim 5.

7. Priority information of the first communication circuit and the second communication circuit is stored in the switching function control unit, When a communication circuit having a higher priority among the first communication circuit and the second communication circuit fails, the switching function control unit switches the input path and the output path of the first switching function unit and the second switching function unit so that communication can be continued using a communication circuit having a lower priority.

7. The communication semiconductor device according to claim 6.

8. When the first communication circuit and the second communication circuit have equal priority, when the first communication circuit or the second communication circuit fails, only communication using the failed first communication circuit or the failed second communication circuit is stopped.

8. The communication semiconductor device according to claim 7.

9. When the switching function control unit detects an abnormality in any of the first communication circuit and the second communication circuit, the diagnostic circuits of the first communication circuit and the second communication circuit, and the mutual diagnostic circuit, the switching function control unit notifies a communication partner of the communication semiconductor device of the abnormality.

4. The communication semiconductor device according to claim 3.

10. When a failure is detected in each of the diagnostic circuits of the first communication circuit and the second communication circuit, the switching function control unit issues a cut-off request to a power supply circuit that supplies power to the communication semiconductor device.

10. The communication semiconductor device according to claim 9.

11. A first component integrating a semiconductor element constituting the first communication circuit, a second component integrating a semiconductor element constituting the second communication circuit, and a third component integrating semiconductor elements constituting each of the first switching function unit, the second switching function unit, and the control circuit are separated from one another via a silicon dioxide film on an SOI substrate.

10. The communication semiconductor device according to claim 9.

12. A SIP structure in which a first semiconductor chip integrating the first communication circuit, a second semiconductor chip integrating the second communication circuit, and a third semiconductor chip integrating the first switching function unit, the second switching function unit, and the control circuit are sealed in the same package.

10. The communication semiconductor device according to claim 9.

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