Electronic control unit

Abstract

Electronic control unit for installation on a vehicle, comprising: - a control section (11, 14) that generates control data for controlling an object, in particular for controlling an engine of the vehicle; - a power section (3) with a drive circuit group (22); - a communication bus (4) arranged between the control section (11) and the power section (3); - a first communication section (15) which transmits the control data via serial communication through the communication bus (4), wherein the drive circuit group (22) generates a driver signal for operating a load arranged on the vehicle; and - a second communication section (21) which is connected to the first communication section (15) via the communication bus (4) to perform serial communication with the first communication section, wherein - the first communication section (15) includes: - Data frame transmission means (S20) that transmit a data frame indicating the control data to the second communication section (21) at a predetermined transmission interval, wherein the data frame contains data that represents a control signal for controlling the electrical load; - Command-frame transmission means (S80) which, in accordance with a command-frame transmission instruction generated by the control section (11,14), transmits a command-frame to the second communication section (21) to instruct it to execute a predetermined process in the second communication section (21), wherein the command-frame (CF) is used to write data to or read data from a register (23), wherein the register (23) stores information that reflects the settings of the power section (3) and information that reflects a state of the power section; - Transmission detection means (S40) that determine whether the data frame is being transmitted to the second communication segment (21) when the command frame transmission instruction is generated; and - a first wait means (S40) that causes the command frame transmission means to delay the transmission of the command frame until the transmission of the data frame is complete, when the transmission detection means (S40) detects that the data frame is currently being transmitted, - where the specified transmission interval is greater than the sum of the data frame transmission time required to transmit the data frame and the command frame transmission time required to transmit the command frame.

Description

[0001] The present invention relates to an electronic control unit that performs serial communication.

[0002] US 5,960,001 A and US 6,111,888 A disclose mechanisms that can be used in an open network with multiple participants or nodes to control the sending of messages sent by different participants or nodes distributed in the network.

[0003] A Micro-Second Bus has been proposed as an alternative communication method to Serial Peripheral Interface (SPI) communication, which is used as a standard for serial communication for so-called power application-specific integrated circuits (ASICs) and multi-channel switch products. A Micro-Second Bus is disclosed, for example, in US 2004 / 0217385 A1.

[0004] The disclosed Micro-Second Bus is configured to transmit a data frame and a command frame. The data frame is transmitted at a data frame transmission clock that occurs at a predetermined constant interval. The command frame is transmitted at arbitrarily selectable times when a command frame transmission instruction is generated.

[0005] In such a Micro-Second Bus, the command frame is transmitted immediately after the command frame transmission instruction is generated, replacing the data frame at the (next) data frame transmission clock. When the command frame transmission instruction is generated, the data frame is not transmitted at the next data frame transmission clock, and the transmission of the data frame is delayed for the number of transmission clocks of the command frame.

[0006] The present invention is made in view of the above-mentioned situation and it is an object of the present invention to provide an electronic control unit for arrangement on a vehicle which transmits a command frame without delaying the transmission of a data frame.

[0007] According to one aspect of the present invention, the electronic control unit includes a control section, a first communication section, a second communication section, a power section having a drive circuit group, and a communication bus arranged between the control section and the power section. The control section generates control data for controlling an object, in particular, for controlling a motor of the vehicle. The first communication section transmits the control data by serial communication through a communication bus. The drive circuit group generates a drive signal for driving a load arranged on the vehicle. The second communication section is connected to the first communication section through the communication bus to perform serial communication with the first communication section.The first communication section includes a data frame transmission means, a command frame transmission means, a transmission determination means, and a first waiting means. The data frame transmission means transmits a data frame representing the control data to the second communication section at a predetermined transmission interval (transmission clock). The data frame includes data representing a control signal for controlling the electrical load. The command frame transmission means transmits a command frame according to a command frame transmission instruction generated by the control section to instruct the second communication section to execute a predetermined process in the second communication section. The command frame is used to write data to or read data from a register.The register stores information that reflects settings of the power section and information that reflects a state of the power section. The transmission detection means determines whether a data frame is currently being transmitted when the command frame transmission instruction is generated. The first wait means causes the command frame transmission means to delay the transmission of the command frame until the transmission of the data frame is completed if the transmission detection means determines that a data frame is currently being transmitted. The predetermined transmission interval is greater than the sum of a data frame transmission time required for the transmission of the data frame and a command frame transmission time required for the transmission of a command frame.

[0008] If the command frame transmission instruction is generated in the electronic control unit during the transmission of a data frame, the command frame transmission starts immediately after the data frame transmission is completed. In this case, the command frame is not transmitted in place of the data frame. The command frame is transmitted without delaying the data frame transmission.

[0009] The above and other objects, features, and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which like parts are designated by like reference numerals. In the drawings: Fig. 1: a block diagram showing a structure of an electronic control unit according to an embodiment of the present invention; Fig.2: a flowchart illustrating a frame transmission process according to the embodiment and Fig. 3: a timing diagram showing a transmission timing of a command frame according to the embodiment.

[0010] An embodiment of the present invention will be described below with reference to the drawings.

[0011] An electronic control unit (1) (hereinafter referred to as ECU (1)) according to the embodiment is arranged on a vehicle to control, for example, an engine (not shown) of the vehicle.

[0012] As in Fig.As shown in Figure 1, the ECU (1) includes a microcomputer (MCN) (2), a power device (PWD) (3), and a micro-second bus (MSB) (4). The microcomputer (2) is arranged between the microcomputer (2) and the power device (3). The microcomputer (2) executes a process for controlling the motor and outputs a control signal for controlling an electrical load, such as controlling an injector mounted on the vehicle.

[0013] The microcomputer (2) includes a CPU (11), a ROM (12), a RAM (13), a timer (14), a micro second bus controller (15) (hereinafter referred to as the MSB controller (15)), and a bus (16). The bus (16) interconnects the CPU (11), the ROM (12), the RAM (13), the timer (14), and the MSB controller (15).

[0014] The CPU (11) executes a process according to a program for controlling the motor. The ROM (12) is a non-volatile memory in which the program executed by the CPU (11) is stored. The RAM (13) is a volatile memory in which a calculation result of the CPU (11) and the like are temporarily stored.

[0015] Although in Fig. While only a single timer (14) is shown in Figure 1, the microcomputer (2) may include multiple timers (14). The plurality of timers (14) may include a timer that outputs a pulse signal that assumes a high level between a predetermined on-timing and a predetermined off-timing, a timer that measures a time period from a rise time to a fall time of the pulse signal input to this timer, and the like.

[0016] The MSB controller (15) controls high-speed serial communication between the microcomputer (2) and the power section (3) via the microsecond bus (4). The MSB controller (15) includes a serializer (not shown) that converts parallel data input to the serializer into serial data and outputs the converted serial data, and a deserializer (not shown) that converts serial data input to the deserializer into parallel data and outputs the converted parallel data.

[0017] The power section (3) includes a micro second bus controller (21) (hereinafter referred to as MSB controller (21)), a driver circuit group (DCG) (22), and a register (23). The MSB controller (21) controls high-speed serial communication performed between the power section (3) and the microcomputer (2) through the micro second bus (4). The MSB controller (21) includes a serializer (not shown) that converts parallel data input to the serializer into serial data and outputs the converted serial data to the deserializer of the MSB controller (15), and a deserializer (not shown) that converts the serial data output to the deserializer from the serializer of the MSB controller (15) into parallel data and outputs the converted parallel data.

[0018] The driver circuit group (22) consists of a plurality of driver circuits. The drive circuit group (22) generates a drive signal for driving the electrical load mounted on the vehicle based on the control signal input from the microcomputer (2) to the drive circuit group (22) through the deserializer of the MSB controller (21), and the drive circuit group (22) outputs this drive signal.

[0019] In Fig. 1, as examples of the driver circuits of the driver circuit group (22), an injector driver circuit (221), a valve driver circuit (222), a heater driver circuit (223), a relay driver circuit (224) and a PRE driver circuit (225) are shown.

[0020] The injector drive circuit (221) generates a drive signal for driving an injector (not shown). The valve drive circuit (222) generates a drive signal for driving a valve (not shown) that adjusts the supply of fuel to the injector. The heater drive circuit (223) generates a drive signal for driving a heater (not shown) of an O2 sensor. The relay drive circuit (224) generates a drive signal for turning a main relay (not shown) on and off. The PRE drive circuit (225) generates a signal for driving a drive circuit that drives a power element that requires a high voltage or a large amount of current.

[0021] The register (23) stores information representing the settings of the power section (3) as well as information representing the state of the power section (3). The micro-second bus (4) includes a downstream bus (31), an upstream bus (32), and a communication clock bus (33).

[0022] The downstream bus (31) transmits the serial data from the MSB controller (15) to the MSB controller (21). In this case, a two-wire system based on the differential voltage method is used.

[0023] The upstream bus (32) transmits the serial data from the MSB controller (21) to the MSB controller (15). In this case, a two-wire system based on the differential voltage method is also used.

[0024] The communication clock bus (33) transmits a clock signal from the MSB controller (15) to the MSB controller (21). In this case, a two-wire system operating according to the differential voltage method is used.

[0025] In the Micro-Second Bus (4), both the downstream bus (31) and the upstream bus (32) communicate in synchronization with the communication clock transmitted by the communication clock bus (33). The maximum clock frequency of the Micro-Second Bus (4) is 40 MHz. The maximum permissible data volume is 32 bits.

[0026] In the ECU (1) constructed as described above, the microcomputer (2) periodically transmits a data frame through the downstream bus (31) to the MSB controller (21) at a frame transmission time point occurring at a predetermined constant interval (clock) (for example, interval (Tc) in Fig.3). The data frame contains data that represents the control signal.

[0027] The microcomputer (2) transmits a command frame (CF) to the MSB controller (21) via the downstream bus (31) whenever a command frame transfer instruction is generated at any time during the process executed by the CPU (1). The command frame (CF) is used to write data to or read data from the register (23).

[0028] If the data frame (DF) and the command frame (CF) are not transmitted within the predetermined constant interval, an invalid frame containing invalid data is transmitted. The invalid frame is also referred to as a passive frame (e.g., (PF) in Fig. 3).

[0029] Next, with reference to Fig.2 describes a frame transmission process. The frame transmission process is executed by the MSB controller (15) for transmitting the frames. The frame transmission process is executed repeatedly when the microcomputer (2) is operating.

[0030] When the frame transmission process begins, the MSB controller (15) determines whether a frame transmission timing has been reached or not, that is, whether a frame transmission timing exists to initiate the transmission of a data frame (DF) (at step (S10)). If it is determined that the frame transmission timing has not been reached (S10: NO), the processing proceeds to step (S30). If it is determined that the frame transmission timing has been reached (S10: YES), the data frame (DF) is transmitted at step (S20). Then, the processing proceeds to step (S30).

[0031] In step (S30), the MSB controller (15) determines whether a command frame transmission instruction has been generated. If it is determined that no command frame transmission instruction has been generated (S30: NO), the frame transmission process is terminated once. If it is determined that a command frame transmission instruction has been generated (S30: YES), the MSB controller (15) determines in step (S40) whether a data frame (DF) is currently being transmitted.

[0032] If it is determined that a data frame (DF) is currently being transmitted (S40: YES), the MSB controller (15) determines in step (S50) whether the transmission of the data frame (DF) has been completed. If it is determined that the transmission of the data frame (DF) has not been completed (S50: NO), the MSB controller (15) repeats the processing of step (S50) and waits for the completion of the transmission of the data frame (DF). If it is determined that the transmission of the data frame (DF) has been completed (S50: YES), the processing proceeds to step (S80).

[0033] If it is determined that no data frame (DF) is currently being transmitted (S40: NO), the MSB controller (15) determines that the passive frame (PF) is currently being transmitted. Consequently, the MSB controller (15) determines in step (S60) whether the data frame transmission remaining time (RT) is greater than a command frame transmission duration (FT). The data frame transmission remaining time (RT) is a period of time from a current time to a subsequent frame transmission time at which the transmission of a subsequent data frame (DF) begins. The command frame transmission duration (FT) is a period of time required to transmit a command frame (CF), wherein the transmission of the command frame (CF) occurs according to the presence of a command frame transmission instruction determined in step (S30).

[0034] If it is determined that the data frame transmission remaining time (RT) is greater than the command frame transmission duration (FT) (S60: YES), processing proceeds to step (S80). If it is determined that the data frame transmission remaining time (RT) is not greater than the command frame transmission duration (FT) (S60: NO), the MSB controller (15) determines in step (S70) whether the transmission of a subsequent data frame (DF) has been completed, which starts at a subsequent frame transmission time. If it is determined that the transmission of the subsequent data frame (DF) has not been completed (S70: NO), the MSB controller (50) repeats the processing of step (S70) and waits for the completion of the transmission of the subsequent data frame (DF). If it is determined that the transmission of the subsequent data frame (DF) has been completed (S70: YES), processing proceeds to step (S80).

[0035] At step (S80), the MSB controller (15) transmits the command frame (CF) in response to the command frame transmission instruction detected at step (S30) and terminates the command frame transmission process once.

[0036] Fig. 3 is a timing diagram illustrating a case where the data frame (DF) is transmitted at the predetermined constant interval (Tc). When a command frame transmission instruction (TR1) is generated at a time (t1) during the transmission of the data frame (DF), the MSB controller (15) transmits a command frame (CF1) at a time (t2) at which the transmission of the data frame (DF) is completed.

[0037] When a command frame transmission instruction (TR2) is generated at a time (t3) during the transmission of the passive frame (PF), the MSB controller (15) starts transmitting a command frame (CF2) at a time (t3) at which the command frame transmission instruction (TR2) is generated, because a data frame transmission remaining time (RT2) is greater than a command frame transmission duration (FT2) required for transmitting the command frame (CF2) in response to the command frame transmission instruction (TR2). In this case, the data frame transmission remaining time (RT2) is a time period from a time at which the command frame transmission instruction (TR2) is generated to the next frame transmission time.

[0038] If a command frame transmission instruction (TR3) is generated at a time (t4) during the transmission of the passive frame (PF), the MSB controller (15) starts the transmission of the command frame (CF3) at a time (t5) at which the transmission of the subsequent data frame (DF) is completed because a data frame transmission remaining time (RT3) is shorter than a command frame transmission duration (FT3) required for the transmission of a command frame (CF3) in response to the command frame transmission instruction (TR3).

[0039] In the present embodiment described above, the ECU (1) includes: the CPU (11) and the timer (14) that generate the control signal for controlling the motor; the MSB controller (15) that transmits the generated control signal via serial communication through the micro-second bus (4); and the MSB controller (21) that is connected to the MSB controller (15) via the micro-second bus (4) so ​​that serial communication can be performed. The MSB controller (15) transmits the data frame (DF) representing the control signal to the MSB controller (21) (S20) and transmits the command frame (CF) to the MSB controller (21) according to the command frame transmission instruction (S80) when the CPU (11) generates the command frame transmission instruction.

[0040] In this case, the constant interval (Tc) is greater than the sum of the data frame transmission duration and the command frame transmission duration (FT). The data frame transmission duration is a period of time required to transmit the data frame (DF), and the command frame transmission duration (FT) is a period of time required to transmit the command frame (CF). The MSB controller (15) determines whether the data frame (DF) is currently being transmitted when the command frame transmission instruction is generated (S40). If it is determined that the data frame (DF) is currently being transmitted (S40: YES), the MSB controller (15) waits to transmit the command frame (CF) until the current transmission of the data frame (DF) is completed (S50).

[0041] Accordingly, if the command frame transmission instruction is generated during data frame transmission, the command frame (CF) transmission starts immediately after the completion of the data frame (DF). In this case, the command frame (CF) is not transmitted in place of the data frame (DF). Therefore, the command frame (CF) is transmitted without delaying the data frame (DF) transmission.

[0042] If the MSB controller (15) determines that the data frame (DF) is not currently being transmitted (S40: NO), the MSB controller (15) determines whether the data frame transmission remaining time (RT) is greater than the command frame transmission duration (FT) (step (S60)). If the MSB controller (15) determines that the data frame transmission remaining time (RT) is greater than the command frame transmission duration (FT) (S60: YES), the MSB controller (15) transmits the command frame (CF) immediately after the command frame transmission instruction is generated. If the MSB controller (15) determines that the data frame transmission remaining time (RT) is not greater than the command frame transmission duration (FT) (S60: NO), the MSB controller (15) waits to transmit the command frame (CF) until the transmission of the subsequent data frame (DF) is completed (S70).

[0043] Accordingly, the transmission of the command frame (CF) begins immediately after the command frame transmission instruction is generated, or immediately after the transmission of the subsequent data frame (DF) is completed if the command frame transmission instruction is generated and no data frame (DF) is currently being transmitted. The command frame (CF) is also transmitted without delaying the transmission of the data frame (DF).

[0044] In the embodiment described above, the CPU (11) and the timer (14) correspond to a control section, and the micro second bus (14) corresponds to a communication bus. The MSB controller (15) corresponds to a first communication section, and the MSB controller (21) corresponds to a second communication section. The processing at step (S20) corresponds to data frame transmission means, and the processing at step (S80) corresponds to command frame transmission means. The processing at step (S40) corresponds to transmission determination means. The processing at step (S50) corresponds to first waiting means, and the processing at step (S60) corresponds to comparison means. The processing at steps (S60) and (S70) corresponds to second waiting means. The constant interval (Tc) corresponds to a transmission interval.

[0045] Further advantages and modifications will readily occur to those skilled in the art. The invention, in its broader sense, is therefore not limited to the specific details, representative devices, and illustrative examples shown and described. LIST OF REFERENCE SYMBOLS 1 Electronic Control Unit (ECU) Electronic Control Unit (ECU) 2 Microcomputer (MCN) Microcomputer (MCN) 3 Power section (PWD) Power device (PWD) 4 Micro Second Bus (MSB) / communication bus Microsecond bus (MSB) / communication bus 11 CPU / control section CPU / control section 12 ROME ROME 13 R.A.M. R.A.M. 14 Timer / control section Timer / control section 15 First MSB controller / First First MSB Controller / first communication communication section 16 bus bus 21 Second MSB controller / Second Second MSB Controller / second communication communication section 22 Drive circuit group / driver circuit group (DCG) Driver circuit group (DCG) 23 register register 31 Downstream Bus Downstream bus 32 Upstream Bus Upstream bus 221 Injector drive circuit Injector Driver Circuit 222 Valve drive circuit Valve driver circuit 223 Heater drive circuit Heater driver circuit 224 Relay drive circuit Relay driver circuit 225 PRE drive circuit PRE-Driver Circuit S20 Data frame transmission medium Data frame transmission means S40 Transfer determination means transmission determination means S50 First remedy First waiting means S60 Comparison agent / second waiting agent Comparison mean / Second waiting means S70 Second waiting method Second waiting means S80 Command frame transmission medium Command frame transmission means DF Data frame Dara frame CF Command Frame Command frame PF Passive frame / invalid frame Passive frame / Invalid frame Tc Constant interval Constant interval RT Data frame transmission remaining time Data frame transmission remaining time FT Command frame transmission time Command frame transmission time TR Command frame transmission instruction Command frame transmission request

Claims

[1] Electronic control unit for installation on a vehicle, comprising: - a control section (11, 14) which generates control data for controlling an object, in particular for controlling an engine of the vehicle; - a power section (3) with a drive circuit group (22); - a communication bus (4) arranged between the control section (11) and the power section (3); - a first communication section (15) which transmits the control data by serial communication through the communication bus (4), wherein the drive circuit group (22) generates a drive signal for driving a load arranged on the vehicle; and - a second communication section (21) connected to the first communication section (15) by the communication bus (4) to carry out serial communication with the first communication section, wherein - the first communication section (15) includes: - data frame transmission means (S20) which transmit a data frame indicating the control data to the second communication section (21) at a predetermined transmission interval, the data frame including data representing a control signal for controlling the electrical load; - Command frame transmission means (S80) which, in accordance with a command frame transmission instruction generated by the control section (11, 14), transmits a command frame to the second communication section (21) to instruct it to execute a predetermined process in the second communication section (21), wherein the command frame (CF) is used to write data into or read data from a register (23), wherein the register (23) stores information representing settings of the power section (3) and information representing a state of the power section; - transmission detection means (S40) for detecting whether the data frame is currently being transmitted to the second communication section (21) when the command frame transmission instruction is generated; and - a first waiting means (S40) which causes the command frame transmission means to delay the transmission of the command frame until the transmission of the data frame is completed, if the transmission detection means (S40) detects that the data frame is currently being transmitted, - where the specified transmission interval is greater than the sum of a data frame transmission time required to transmit the data frame and a command frame transmission time required to transmit the command frame. [2] Electronic control unit according to claim 1, characterized by that the first communication section (15) includes: - a comparison means (S60) which determines whether a data frame transmission remaining time extending from a current time to a time at which the transmission of a next data frame begins is greater than the command frame transmission time when the transmission determination means (S40) determines that the data frame is not currently being transmitted; and - a second waiting means (S60, S70) which, on the one hand, causes the command frame transmission means (S80) to transmit the command frame immediately after the generation of the command frame transmission instruction if the comparison means (S60) determines that the data frame transmission remaining time is greater than the command frame transmission duration, and, on the other hand, causes the command frame transmission means (S80) to delay the transmission of the command frame until the transmission of the subsequent data frame is completed if the comparison means (S60) determines that the data frame transmission remaining time is not greater than the command frame transmission duration.

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