Display device for vehicle

Abstract

The invention provides a display device for a vehicle. A control unit (SOC (1)) turns off a first power supply circuit (54) and a second power supply circuit (55) during a travel completion operation of a vehicle, and performs data storage processing before a transition to a power saving mode. In a data storage process, a part of vehicle information stored in a memory (RAM (17)) is used as to-be-stored data (D), also referred to as stored vehicle information, the to-be-stored data (D) is separately stored in a memory (ROM (16)) and an in-core memory (in-core RAM) which always supplies power, and the in-core RAM is included in an internal memory (11B1) of a second processor core (11B). According to the vehicle display device of the present invention, the number of writes of stored vehicle information into a non-volatile memory can be reduced.

Description

Technical Field

[0001] The present invention relates to a display device for a vehicle. Background Art

[0002] Patent Document 1 discloses a vehicle display device that enters a power-saving sleep mode when an ignition switch is turned off.

[0003] In the end processing before entering the sleep mode, the vehicle display device saves vehicle information such as the total travel distance and the past fuel consumption history stored in the volatile working memory (RAM) in a non-volatile memory such as an EEPROM.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-175617 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, when the number of writes to a nonvolatile memory such as an EEPROM exceeds the guaranteed number, the possibility of not being able to store data correctly increases, and therefore it is desired to reduce the number of writes for data storage.

[0009] In view of the above-mentioned problems, an object of the present invention is to provide a vehicle display device capable of reducing the number of times vehicle information is written to a nonvolatile memory.

[0010] Means for solving problems

[0011] The vehicle display device of the present invention has:

[0012] a volatile working memory storing vehicle information; and

[0013] A control unit that displays the vehicle information stored in the working memory on a display, wherein the vehicle display device is characterized by comprising:

[0014] A non-volatile first storage memory;

[0015] a volatile second storage memory having a smaller capacity than the first storage memory;

[0016] an on / off power supply that supplies power to the first storage memory, the work memory, and the display, and is capable of turning the power supply on / off; and

[0017] a normally-on power supply that always supplies power to the second storage memory,

[0018] When the vehicle is terminated from driving, the control unit turns the on / off power off and performs data saving processing before switching to the power saving mode.

[0019] In the data saving process, part of the vehicle information stored in the working memory is dividedly stored in the first saving memory and the second saving memory as saved vehicle information.

[0020] Effects of the Invention

[0021] According to the present invention, it is possible to provide a vehicle display device capable of reducing the number of times vehicle information is written to a nonvolatile memory. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a diagram showing a system configuration of a vehicle display device.

[0023] Figure 2 It is a diagram showing a power supply structure of a vehicle display device.

[0024] Figure 3 This is a diagram for explaining the data saving process.

[0025] Explanation of symbols

[0026] M: vehicle display device; 1: SOC (control unit); 11A: 1st processor core; 11B: 2nd processor core; 11B1: internal memory (2nd storage memory); 11C: 3rd processor core; 12: PVT monitor unit; 13: communication unit; 14: video input unit; 15: display control unit; 16: ROM (1st storage memory); 17: RAM (operating memory); 18: 2D drawing unit; 19: 3D drawing unit; 2: display; 3: timing unit; 4: reset circuit; 5: power supply circuit; 51: diode; 52: capacitor; 53: 3rd power supply circuit (normally open power supply); 54: 1st power supply circuit (on / off power supply); 55: 2nd power supply circuit (on / off power supply); BAT: vehicle battery; C: vehicle camera; E: vehicle control unit; N: in-vehicle network. DETAILED DESCRIPTION

[0027] (Structure of a vehicle display device)

[0028] The vehicle display device M is a device that displays vehicle information to a passenger of the vehicle. The vehicle display device M is mounted on a dashboard of the vehicle.

[0029] Vehicle information includes, for example, vehicle speed, engine speed, vehicle automatic control status, warning lights, remaining fuel (remaining energy), tire pressure, route navigation, images from the onboard camera, total driving distance, elapsed time, average fuel consumption, instantaneous fuel consumption, setting data, etc. The elapsed time includes, for example, the time since the last maintenance.

[0030] The vehicle automatic control state refers to the operation state of the automatic driving mode in which the vehicle automatically controls the acceleration, deceleration or steering of the vehicle. Examples of the automatic driving mode include an automatic control mode in which the vehicle keeps a constant distance from the vehicle ahead and travels at a constant speed, an automatic lane change mode in which the vehicle controls the steering to change lanes when the driver operates the direction indicator, and an automatic parking mode in which the vehicle moves to a place where the vehicle is judged to be able to park and parks the vehicle.

[0031] like Figure 1 As shown, the vehicle display device M includes a SOC (System On a Chip) 1 , a display 2 , a timer 3 , a reset circuit 4 , and a power supply circuit 5 .

[0032] SOC1 is an integrated semiconductor chip in which all functions required for the operation of the vehicle display device M are installed on one integrated circuit chip. The functions required for the operation of the vehicle display device M refer to the function of displaying vehicle information on the display 2 (instrument display function). SOC1 obtains the image signal obtained by photographing the surroundings of the vehicle from the vehicle-mounted camera C that photographs the surroundings of the vehicle, and displays it on the display 2 as needed. In addition, SOC1 displays the vehicle information obtained from the vehicle-mounted control unit E via the in-vehicle network N on the display 2. In addition, the details of SOC1 will be described later.

[0033] The display 2 is a device that displays images, such as a liquid crystal display or an organic EL display, etc. The display 2 receives an image signal output from the SOC 1 and displays an image based on the image signal on a screen.

[0034] The timing unit 3 is an RTC (real time clock) IC that always keeps time, and sends the timed date information to the SOC1 (the second processor core 11B described later). This date information is used, for example, to calculate the "elapsed time since the last maintenance", which is used to notify the "next oil replacement time". In order to always keep time, the timing unit 3 is always supplied with power from the third power supply circuit 53 (normally open power supply) described later to operate.

[0035] The reset circuit 4 is a reset IC that outputs a reset signal for starting (restarting) the SOC 1. When the output voltage of the first power supply circuit 54 described later reaches a predetermined voltage (e.g., 5.0 V), the reset circuit 4 outputs a reset signal to the SOC 1 to start the SOC 1. The start-up process of the SOC 1 by the reset circuit 4 will be described later.

[0036] The power circuit 5 transforms the battery power of about 7 to 12 V supplied from the vehicle-mounted battery BAT, and supplies power to the SOC 1, the display 2, the timer unit 3, and the reset circuit 4. The power circuit 5 will be described in detail later.

[0037] (Structure of SOC)

[0038] like Figure 1 As shown, the SOC 1 has built-in a first processor core 11A, a second processor core 11B, a third processor core 11C, a PVT monitor unit 12, a communication unit 13, a video input unit 14, a display control unit 15, a ROM 16, a RAM 17, a 2D rendering unit 18, and a 3D rendering unit 19.

[0039] The first processor core 11A is a computing device that functions independently from the other cores.

[0040] The first processor core 11A operates by executing first processor core software including a first boot loader, an OS (Operating System), normal screen drawing software, update function software, normal screen drawing image data, and normal screen drawing voice data.

[0041] The first boot loader loads the first processor core software stored in the ROM 16 into the RAM 17, and enables the first processor core 11A to execute the first processor core software. The first boot loader has a function of verifying the integrity of the first processor core software during or after the first processor core software is loaded. The integrity verification uses, for example, a digital signature technology such as ECDSA (Elliptic Curve Digital Signature Algorithm) to check whether the first processor core software has defects such as deletion or modification.

[0042] The OS is basic software for executing general screen drawing software or update function software. For example, Linux OS is used as the OS.

[0043] The normal screen drawing software is an application program that runs on the OS. In order to display a normal screen based on 3D drawing on the display 2 in a normal display mode described later, the normal screen drawing software draws an image showing vehicle information in a corresponding area of ​​the RAM 17 .

[0044] The update function software is an application program that runs on the OS. The update function software is a program for updating the software of each processor core 11A, 11B, 11C.

[0045] The image data for drawing a normal screen and the voice data for drawing a normal screen are data used by the normal screen drawing software to draw a normal screen.

[0046] The second processor core 11B is a computing device that functions independently from other cores. The second processor core 11B has an internal memory 11B1 built in. The internal memory 11B1 has an in-core ROM and an in-core RAM. The second processor core 11B loads the program stored in the in-core ROM into the in-core RAM to start operation. Compared with the ROM 16, the capacity of the in-core RAM is smaller.

[0047] The second processor core 11B is a secure processor core that decodes and executes an encrypted instruction code (encrypted instruction code). The second processor core 11B has a core unique key storage unit that stores a unique key (core unique key). The core ROM of the internal memory 11B1 stores the encrypted program in a non-rewritable form. The second processor core 11B uses the core unique key to authenticate and decode the encrypted instruction code of the program stored in the core ROM to execute it.

[0048] The second processor core 11B loads the second processor core software stored in the in-core ROM or ROM 16 into the in-core RAM or RAM 17 for execution. The second processor core software includes a second boot loader and communication software.

[0049] The second boot loader is a program stored in the ROM in the core, and is started in a state where the integrity is guaranteed. When the second boot loader is started, the integrity of the first boot loader or the third boot loader described later is verified. In addition, the second boot loader loads the communication software from the ROM 16 and verifies the integrity of the communication software. The verification method used for these verifications is, for example, the same as that of the first boot loader.

[0050] The communication software is a program for communicating with the vehicle-mounted device via the communication unit 13. The communication software acquires vehicle information such as the running speed and engine speed of the vehicle from the vehicle-mounted ECU.

[0051] The third processor core 11C is a computing device that functions independently from the other cores.

[0052] The third processor core 11C operates by executing third processor core software. The third processor core software includes a third boot loader, startup screen drawing software, startup screen drawing image data, and startup screen drawing voice data.

[0053] The third boot loader loads the third processor core software stored in the ROM 16 into the RAM 17, and the third processor core 11C can execute the third processor core software. The third boot loader has a function of verifying the integrity of the third processor core software during or after the loading of the third processor core software. The verification method is, for example, the same as that of the second boot loader.

[0054] In the startup display mode, the startup screen drawing software draws an image representing vehicle information in a corresponding area of ​​the RAM 17 in order to display a 2D-drawn startup screen on the display 2 .

[0055] Furthermore, in the emergency display mode, the startup screen drawing software draws an image showing vehicle information and a warning message in a corresponding area of ​​the RAM 17 in order to display a 2D-drawn alternative screen on the display 2 .

[0056] The image data for drawing a startup screen and the voice data for drawing a startup screen are data used by the startup screen drawing software to draw a startup screen or an alternative screen.

[0057] The PVT (Process, Voltage and Temperature) monitor unit 12 is a functional block that monitors whether the operation of each processor core 11A to 11C is normal. The PVT monitor unit 12 monitors whether the power supply voltage and operation clock supplied to each processor core 11A to 11C are normal. In addition, the PVT monitor unit 12 monitors whether the temperature of each processor core 11A to 11C is within the operation guarantee range.

[0058] The communication unit 13 is a functional block that communicates according to a predetermined communication protocol. The predetermined communication protocol is, for example, CAN (Controller Area Network), LIN (Local Interconnect Network), MOST (Media Oriented Systems Transport), Ethernet, etc. The communication unit 13 communicates with the vehicle control unit E via the in-vehicle network N to obtain vehicle information and stores it in the RAM 17.

[0059] The video input unit 14 is a functional block that inputs a video signal of a prescribed specification. The video signal of the prescribed specification refers to NTSC (National Television System Committee), LVDS (Low Voltage Differential Signaling), HDMI (registered trademark) (High-Definition Multimedia Interface), etc. The video input unit 14 inputs a video signal obtained by shooting the surroundings of the vehicle from the vehicle-mounted camera C, and stores it in the RAM 17.

[0060] The display control unit 15 is a functional block that outputs a video signal of a predetermined standard to the display 2, and displays an image representing vehicle information on the display 2. The video signal of the predetermined standard is LVDS or HDMI (registered trademark), for example.

[0061] The ROM 16 is a rewritable nonvolatile memory, such as a NAND flash memory or a NOR flash memory.

[0062] The RAM 17 is a volatile memory, for example, a DDR SDRAM that transfers data using a DDR (Double Data Rate) method. The RAM 17 is a working memory that stores data calculated by the processor cores 11A to 11C or the above-mentioned vehicle information.

[0063] The 2D rendering unit 18 is a functional block that performs two-dimensional vector graphics or raster graphics image rendering.

[0064] The 3D rendering unit 19 is a functional block that performs three-dimensional computer graphics image rendering.

[0065] (Structure of power supply circuit)

[0066] like Figure 2 As shown, the power supply circuit 5 includes a diode 51 , a capacitor 52 , a first power supply circuit 54 , a second power supply circuit 55 , and a third power supply circuit 53 .

[0067] The diode 51 is a diode for backflow prevention provided in the power supply path from the vehicle-mounted battery BAT to each power circuit 53 to 55. That is, the diode 51 allows power supply from the vehicle-mounted battery BAT to each power circuit 53 to 55, while preventing current from flowing from each power circuit 53 to 55 to the vehicle-mounted battery BAT side.

[0068] The capacitor 52 is a capacitor for preventing instantaneous interruption of the power supply path from the vehicle-mounted battery BAT to each power supply circuit 53 to 55. That is, the capacitor 52 releases the electricity stored during the power supply when the power supply is interrupted, and maintains the power supply state even when the power supply is interrupted.

[0069] The first power supply circuit 54 is a stabilized power supply circuit that steps down the battery power supplied from the vehicle-mounted battery BAT and supplies power to the communication unit 13 or the second power supply circuit 55. For example, the first power supply circuit 54 is a series regulator or a switching power supply circuit that steps down the battery power to a voltage of 5.0 V and supplies it. In addition, the power supplied by the first power supply circuit 54 is also input to the reset circuit 4 as a signal for reset determination.

[0070] The second power supply circuit 55 is a stabilized power supply circuit that steps down the 5V power supply supplied from the first power supply circuit 54 and supplies power to the display 2 or the SOC 1 (the components of the SOC 1 other than the second processor core 11B and the communication unit 13). For example, the second power supply circuit 55 is a series regulator or a switching power supply circuit that steps down the 5V power supply to a voltage such as 3.3V, 1.8V, or 0.8V and supplies the power.

[0071] The third power supply circuit 53 is a stabilized power supply circuit that steps down the battery power and supplies power to the second processor core 11B, the internal memory 11B1 (in-core RAM), the timer unit 3, and the reset circuit 4. For example, the third power supply circuit 53 is a series regulator or a switching power supply circuit that steps down the battery power to a voltage of 3.3V or 1.8V and supplies it.

[0072] The third power supply circuit 53 is a normally-on power supply that always supplies power, and the first power supply circuit 54 and the second power supply circuit 55 are on / off power supplies that can turn the power supply on / off. The power supply by the first power supply circuit 54 is turned on / off by the second processor core 11B. In addition, the power supply by the second power supply circuit 55 is turned on / off in conjunction with the on / off of the first power supply circuit 54 that supplies power to the second power supply circuit 55.

[0073] (Power saving mode)

[0074] When the vehicle driving function is terminated, the vehicle display device M switches to the power saving mode until the vehicle driving function is restarted. The switching of the power saving mode is controlled by the second processor core 11B outputting a control signal S to the first power supply circuit 54 .

[0075] The second processor core 11B determines the start / end of the vehicle's driving function based on the state of the start switch included in the vehicle information obtained from the vehicle-mounted control unit E via the in-vehicle network N. If it is an engine vehicle, the start switch is an ignition switch (ignition key), and if it is an electric vehicle, the start switch is a power switch.

[0076] When determining that the driving function of the vehicle has ended, the second processor core 11B stops the power output of the first power supply circuit 54 (including the second power supply circuit 55 ) Thus, the vehicle display device M shifts to the power saving mode.

[0077] When determining that the vehicle's running function has started to be activated, the second processor core 11B starts power output from the first power circuit 54 (including the second power circuit 55 ) Thus, the vehicle display device M shifts from the power saving mode to the normal operation mode.

[0078] In the power saving mode, power is not supplied to components other than components supplied with power by the third power supply circuit 53 (the second processor core 11B, the internal memory 11B1, the timer unit 3, and the reset circuit 4), so that power consumption is reduced.

[0079] (SOC startup process)

[0080] When the vehicle driving function is started, the reset circuit 4 starts the SOC 1. The reset circuit 4 monitors the output voltage of the first power circuit 54, responds to the start of the power output of the first power circuit 54 by the second processor core 11B, and when the output voltage of the first power circuit 54 becomes a predetermined voltage (e.g., 5V), the reset circuit 4 outputs a reset signal to the SOC 1 and starts the SOC 1.

[0081] According to the startup process of SOC1, reset circuit 4 is operated based on the output voltage of first power circuit 54 which is higher than that of second power circuit 55. Therefore, even when the battery power voltage drops, reset circuit 4 can be properly operated to start SOC1.

[0082] (Data storage processing)

[0083] When the vehicle display device M enters the power saving mode, the power supply to the RAM 17 is cut off, so the data held by the RAM 17 is completely deleted. Among the data held by the RAM 17, there is vehicle information that needs to be continuously held (hereinafter, appropriately referred to as data to be saved D), and this vehicle information is saved in another memory before the power supply to the RAM 17 is cut off. The data to be saved D includes, for example, the total travel distance (ODO), the elapsed time (for example, the elapsed time from the last maintenance), the fuel consumption, the electricity fee, and the display screen parameters (for example, the screen setting information, the display screen information at the end of the travel).

[0084] Conventionally, such data saving processing is performed by writing the data D to be saved on RAM 17 to ROM 16. However, when the number of writes to ROM 16 by data saving is greater than the guaranteed number of writes to ROM 16, the possibility of not being able to store data correctly increases, so it is desired to reduce the number of writes for data saving.

[0085] Therefore, if Figure 3 As shown, before the second processor core 11B of the SOC 1 shifts to the power saving mode, the data D to be saved on the RAM 17 is stored separately in the in-core RAM of the internal memory 11B1 and the ROM 16. In particular, the high-update frequency data DH with a high update frequency among the data to be saved D is saved in the in-core RAM of the internal memory 11B1, and the low-update frequency data DL with a low update frequency is saved in the ROM 16. According to such a data saving process, the number of times of writing to the ROM 16 can be reduced compared with saving all the data to be saved D in the ROM 16.

[0086] For example, when the data D to be saved is the total driving distance, the high-order bits (for example, bits above 1 km) in the total driving distance are set as low-update frequency data DL, and the low-order bits (bits less than 1 km) are set as high-update frequency data DH.

[0087] Furthermore, when the data D to be stored is the elapsed time, the month data, day data, and minute data of the elapsed time are set as the low-update frequency data DL, and the second data is set as the high-update frequency data DH.

[0088] In addition, when the data D to be saved is fuel consumption or electricity bill, the high-order data (for example, above 1 km / L) in the fuel consumption or electricity bill is set as low-update frequency data DL, and the low-order data (less than 1 km / L) is set as high-update frequency data DH.

[0089] Furthermore, when the data D to be stored is a display screen parameter, the screen setting information in the display screen parameter is set to the low update frequency data DL, and the display screen information at the end of driving is set to the high update frequency data.

[0090] The above is the description of the embodiment of the vehicle display device M of the present invention.

[0091] The vehicle display device M of the present invention comprises: a volatile RAM 17 storing vehicle information; and a SOC 1 which displays the vehicle information stored in the RAM 17 on the display 2. In addition, the vehicle display device M comprises: a nonvolatile ROM 16; and a volatile in-core RAM (included in the internal memory 11B1 of the second processor core 11B) whose capacity is smaller than that of the ROM 16. Furthermore, the vehicle display device M comprises: a first power supply circuit 54 and a second power supply circuit 55 which can supply power to the ROM 16, the RAM 17, and the display 2 and turn on / off the power supply; and a third power supply circuit 53 which always supplies power to the in-core RAM. When the SOC 1 performs the vehicle driving end operation, the first power supply circuit 54 and the second power supply circuit 55 are turned off, and a data saving process is performed before the vehicle is transferred to the power saving mode. In the data saving process, a part of the vehicle information stored in the RAM 17 is stored as data to be saved D (save vehicle information) and is stored separately in the ROM 16 and the in-core RAM. This can reduce the number of times the data D to be stored is written to the ROM 16 , compared to storing all the data D to be stored in the ROM 16 .

[0092] In addition, during the data saving process, the SOC 1 stores the data with low update frequency in the ROM 16, and stores the data with high update frequency in the in-core RAM. Thus, the data stored in the ROM 16 (low update frequency data DL) and the data stored in the in-core RAM (high update frequency data DH) can be appropriately allocated, and the number of writes to the ROM 16 can be more reliably reduced.

[0093] In addition, the data D to be saved includes any one of the total driving distance, elapsed time, fuel consumption, electricity charges and display screen parameters. The high-order data in the total driving distance is set as data with low update frequency, and the low-order data is set as data with high update frequency. In addition, the monthly data, daily data and minute data in the elapsed time are set as data with low update frequency, and the second data is set as data with high update frequency. In addition, the high-order data in fuel consumption or electricity charges is set as data with low update frequency, and the low-order data is set as data with high update frequency. In addition, the screen setting information in the display screen parameters is set as data with low update frequency, and the display screen information at the end of driving is set as data with high update frequency. In this way, the data stored in ROM16 (low update frequency data DL) and the data stored in the RAM in the core (high update frequency data DH) can be clearly and appropriately allocated.

Claims

1. A vehicle display device, comprising: a volatile working memory storing vehicle information; and A control unit that displays the vehicle information stored in the work memory on a display, wherein the vehicle display device is characterized in that: The vehicle display device comprises: A non-volatile first storage memory; a volatile second storage memory having a smaller capacity than the first storage memory; An on / off power supply that supplies power to the first storage memory, the work memory, and the display, and can turn the power supply on / off; as well as a normally-on power supply that always supplies power to the second storage memory, When the vehicle is terminated from driving, the control unit turns the on / off power off and performs data saving processing before switching to the power saving mode. In the data saving process, a part of the vehicle information stored in the working memory is used as saved vehicle information, and the saved vehicle information is stored separately in the first saving memory and the second saving memory.

2. The vehicle display device according to claim 1, characterized in that: In the data storage process, the control unit storing data with a low updating frequency in the stored vehicle information in the first storage memory, Data with a high update frequency among the stored vehicle information is stored in the second storage memory.

3. The vehicle display device according to claim 2, characterized in that: The stored vehicle information includes any one of the total driving distance, elapsed time, fuel consumption, electricity cost and display screen parameters, The high-order data in the total driving distance is set as data with a low update frequency, and the low-order data in the total driving distance is set as data with a high update frequency, The monthly data, daily data and minute data in the elapsed time are set as data with a low updating frequency, and the second data in the elapsed time is set as data with a high updating frequency, The high-order data of the fuel consumption or the electricity fee is set as data with a low update frequency, and the low-order data of the fuel consumption or the electricity fee is set as data with a high update frequency, The screen setting information in the display screen parameters is set to data with a low updating frequency, and the display screen information at the end of driving in the display screen parameters is set to data with a high updating frequency.

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